android: WIP snapshot manager

Former-commit-id: 7b39e4ac1ea86262a0a1ccf95639382f20801d92

AndroidApp/app/src/main/AndroidManifest.xml

@@ -13,10 +13,17 @@
         android:supportsRtl="true"
         android:theme="@style/AppTheme">
         <activity
-            android:name="com.mrmichel.rustdroid_emu.ui.EmulatorActivity"
+            android:name=".ui.snapshots.SnapshotActivity"
+            android:label="@string/title_activity_snapshot"
+            ></activity>
+        <activity
+            android:name=".ui.RomListActivity"
+            android:label="@string/title_activity_rom_list" />
+        <activity
+            android:name=".ui.EmulatorActivity"
             android:label="@string/title_activity_emulator"
-            android:theme="@style/AppTheme.NoActionBar"></activity>
+            android:theme="@style/AppTheme.NoActionBar" />
-        <activity android:name="com.mrmichel.rustdroid_emu.ui.SplashActivity">
+        <activity android:name=".ui.SplashActivity">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
 

AndroidApp/app/src/main/java/com/mrmichel/rustboyadvance/EmulatorBindings.java

@@ -15,11 +15,12 @@ public class EmulatorBindings {
      * Open a new emulator context
      * @param bios bytearray of the GBA bios
      * @param rom bytearray of the rom to run
+     * @param frameBuffer frameBuffer render target
      * @param save_name name of the save file TODO remove this
      * @return the emulator context to use pass to other methods in this class
      * @throws NativeBindingException
      */
-    public static native long openEmulator(byte[] bios, byte[] rom, String save_name) throws NativeBindingException;
+    public static native long openEmulator(byte[] bios, byte[] rom, int[] frameBuffer, String save_name) throws NativeBindingException;
 
     /**
      * Make the emulator boot directly into the cartridge
@@ -41,15 +42,25 @@ public class EmulatorBindings {
      * Runs the emulation for a single frame.
      * @param ctx
      * @param frame_buffer will be filled with the frame buffer to render
-     * @return
-     * @throws NativeBindingException
      */
-    public static native void runFrame(long ctx, int[] frame_buffer) throws NativeBindingException;
+    public static native void runFrame(long ctx, int[] frame_buffer);
+
+    /**
+     * @param ctx
+     * @return The loaded ROM title
+     */
+    public static native String getGameTitle(long ctx);
+
+    /**
+     * @param ctx
+     * @return The loaded ROM game code
+     */
+    public static native String getGameCode(long ctx);
+
 
     /**
      * Sets the keystate
      * @param keyState
-     * @return non-zero value on failure
      */
     public static native void setKeyState(long ctx, int keyState);
 

AndroidApp/app/src/main/java/com/mrmichel/rustdroid_emu/core/Emulator.java

@@ -1,5 +1,7 @@
 package com.mrmichel.rustdroid_emu.core;
 
+import android.graphics.Bitmap;
+
 import com.mrmichel.rustboyadvance.EmulatorBindings;
 
 public class Emulator {
@@ -29,7 +31,7 @@ public class Emulator {
         return frameBuffer;
     }
 
-    public synchronized void runFrame() throws EmulatorBindings.NativeBindingException {
+    public synchronized void runFrame() {
         EmulatorBindings.setKeyState(this.ctx, this.keypad.getKeyState());
         EmulatorBindings.runFrame(this.ctx, this.frameBuffer);
     }
@@ -39,18 +41,18 @@ public class Emulator {
     }
 
 
-    public byte[] saveState() throws EmulatorBindings.NativeBindingException {
+    public synchronized byte[] saveState() throws EmulatorBindings.NativeBindingException {
         return EmulatorBindings.saveState(this.ctx);
     }
 
 
-    public void loadState(byte[] state) throws EmulatorBindings.NativeBindingException {
+    public synchronized void loadState(byte[] state) throws EmulatorBindings.NativeBindingException {
         EmulatorBindings.loadState(this.ctx, state);
     }
 
 
     public synchronized void open(byte[] bios, byte[] rom, String saveName) throws EmulatorBindings.NativeBindingException {
-        this.ctx = EmulatorBindings.openEmulator(bios, rom, saveName);
+        this.ctx = EmulatorBindings.openEmulator(bios, rom, this.frameBuffer, saveName);
     }
 
     public synchronized void close() {
@@ -61,6 +63,14 @@ public class Emulator {
         }
     }
 
+    public String getGameCode() {
+        return EmulatorBindings.getGameCode(ctx);
+    }
+
+    public String getGameTitle() {
+        return EmulatorBindings.getGameTitle(ctx);
+    }
+
     public boolean isOpen() {
         return this.ctx != -1;
     }

AndroidApp/app/src/main/java/com/mrmichel/rustdroid_emu/core/Snapshot.java

@@ -0,0 +1,50 @@
+package com.mrmichel.rustdroid_emu.core;
+
+import android.graphics.Bitmap;
+
+import java.io.ByteArrayOutputStream;
+import java.io.File;
+
+public class Snapshot {
+    private Bitmap preview;
+    private String gameCode;
+    private String gameTitle;
+    private long timestamp;
+    private File file;
+
+    public Snapshot(File file, String gameCode, String gameTitle, Bitmap preview) {
+        this.file = file;
+        this.gameCode = gameCode;
+        this.gameTitle = gameTitle;
+        this.preview = preview;
+        this.timestamp = System.currentTimeMillis();
+    }
+
+    public Snapshot(File file, String gameCode, String gameTitle, Bitmap preview, long timestamp) {
+        this.file = file;
+        this.gameCode = gameCode;
+        this.gameTitle = gameTitle;
+        this.preview = preview;
+        this.timestamp = timestamp;
+    }
+
+    public String getGameCode() {
+        return gameCode;
+    }
+
+    public String getGameTitle() {
+        return gameTitle;
+    }
+
+    public long getTimestamp() {
+        return timestamp;
+    }
+
+    public Bitmap getPreview() {
+        return preview;
+    }
+
+    public byte[] load() {
+        return SnapshotManager.readCompressedFile(this.file);
+    }
+}

AndroidApp/app/src/main/java/com/mrmichel/rustdroid_emu/core/SnapshotManager.java

@@ -0,0 +1,230 @@
+package com.mrmichel.rustdroid_emu.core;
+
+import android.content.ContentValues;
+import android.content.Context;
+import android.database.Cursor;
+import android.database.sqlite.SQLiteDatabase;
+import android.database.sqlite.SQLiteOpenHelper;
+import android.graphics.Bitmap;
+import android.graphics.BitmapFactory;
+import android.util.Log;
+
+import java.io.BufferedInputStream;
+import java.io.BufferedReader;
+import java.io.ByteArrayOutputStream;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.InputStreamReader;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import java.sql.Timestamp;
+import java.util.ArrayList;
+import java.util.zip.GZIPInputStream;
+import java.util.zip.GZIPOutputStream;
+
+public class SnapshotManager {
+    private static final String TAG = "SnapshotManager";
+
+    private static final String SNAPSHOT_ROOT = "snapshots";
+    private static final String DB_NAME = "snapshots";
+
+    static SnapshotManager instance;
+
+    private Context context;
+
+    private SnapshotDatabaseHelper dbHelper;
+
+    public class SnapshotDBEntry {
+        String gameCode;
+        String gameTitle;
+        File previewFile;
+        File snapshotFile;
+        Timestamp timestamp;
+
+        public SnapshotDBEntry(String gameCode, File previewFile, File snapshotFile, Timestamp timestamp) {
+            this.gameCode = gameCode;
+            this.previewFile = previewFile;
+            this.snapshotFile = snapshotFile;
+            this.timestamp = timestamp;
+        }
+    }
+
+    public class SnapshotDatabaseHelper extends SQLiteOpenHelper {
+        public static final String TABLE_NAME = "snapshot_table";
+        private Context context;
+
+        public SnapshotDatabaseHelper(Context context) {
+            super(context, DB_NAME, null, 1);
+            this.context = context;
+        }
+
+        @Override
+        public void onCreate(SQLiteDatabase db) {
+            db.execSQL("create table " + TABLE_NAME +
+                    " (id INTEGER PRIMARY KEY, gameCode TEXT, gameTitle TEXT, timestamp DATETIME DEFAULT CURRENT_TIMESTAMP, previewImageFile TEXT, dataFile TEXT)"
+            );
+        }
+
+        public void insertSnapshot(String gameCode, String gameTitle, File previewCacheFile, File snapshotDataFile) {
+            SQLiteDatabase db = this.getWritableDatabase();
+            ContentValues values = new ContentValues();
+            values.put("gameCode", gameCode);
+            values.put("gameTitle", gameTitle);
+            values.put("previewImageFile", previewCacheFile.getPath());
+            values.put("dataFile", snapshotDataFile.getPath());
+            db.insertOrThrow(TABLE_NAME, null, values);
+            db.close();
+        }
+
+        public ArrayList<Snapshot> getEntriesByQuery(String query) {
+            ArrayList<Snapshot> arrayList = new ArrayList<>();
+
+            SQLiteDatabase db = this.getWritableDatabase();
+            Cursor cursor = db.rawQuery(query, null);
+
+            if (cursor.moveToFirst()) {
+                do {
+                    String gameCode = cursor.getString(1);
+                    String gameTitle = cursor.getString(2);
+                    Timestamp timestamp = Timestamp.valueOf(cursor.getString(3));
+                    File previewImageFile = new File(cursor.getString(4));
+                    File dataFile = new File(cursor.getString(5));
+
+                    byte[] previewData = readCompressedFile(previewImageFile);
+                    Bitmap previewBitmap = BitmapFactory.decodeByteArray(previewData, 0, previewData.length);
+
+                    arrayList.add(new Snapshot(dataFile, gameCode, gameTitle, previewBitmap, timestamp.getTime()));
+                } while (cursor.moveToNext());
+            }
+
+            cursor.close();
+            db.close();
+            return arrayList;
+        }
+
+        public ArrayList<Snapshot> getAllEntries() {
+            return getEntriesByQuery("SELECT * FROM " + TABLE_NAME + " ORDER BY timestamp DESC ");
+        }
+
+        public ArrayList<Snapshot> getAllEntries(String gameCode) {
+            return getEntriesByQuery("SELECT * FROM " + TABLE_NAME + "where gameCode = " + gameCode + " ORDER BY timestamp DESC ");
+        }
+
+        @Override
+        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
+
+        }
+    }
+
+    private SnapshotManager(Context context) {
+        this.context = context;
+        this.dbHelper = new SnapshotDatabaseHelper(this.context);
+//        this.snapshotDB = context.openOrCreateDatabase("snapshots", Context.MODE_PRIVATE, null);
+    }
+
+    public static SnapshotManager getInstance(Context context) {
+        if (instance == null) {
+            instance = new SnapshotManager(context);
+        }
+        return instance;
+    }
+
+    private static String byteArrayToHexString(final byte[] bytes) {
+        StringBuilder sb = new StringBuilder();
+        for (byte b : bytes) {
+            sb.append(String.format("%02x", b & 0xff));
+        }
+        return sb.toString();
+    }
+
+    private static String getHash(final byte[] bytes) {
+        MessageDigest md;
+        try {
+            md = MessageDigest.getInstance("SHA-256");
+        } catch (NoSuchAlgorithmException e) {
+            // impossible
+            Log.e("SnapshotManager", "SHA-256 algo not found");
+            return null;
+        }
+
+        md.update(bytes);
+        return byteArrayToHexString(md.digest());
+    }
+
+    private File getPreviewsDir(String gameCode) {
+        File d = new File(context.getFilesDir(), SNAPSHOT_ROOT + "/previews");
+        d.mkdirs();
+        return d;
+    }
+
+
+    private File getSnapshotDir(String gameCode) {
+        File d = new File(context.getFilesDir(), SNAPSHOT_ROOT + "/data");
+        d.mkdirs();
+        return d;
+    }
+
+    public static void writeCompressedFile(File file, byte[] bytes) {
+        try {
+            FileOutputStream fos = new FileOutputStream(file);
+            GZIPOutputStream gos = new GZIPOutputStream(fos);
+
+            gos.write(bytes);
+            gos.close();
+            fos.close();
+        } catch (Exception e) {
+            Log.e(TAG, "failed to write compressed file " + file.toString() + " error: " + e.getMessage());
+        }
+    }
+
+    public static byte[] readCompressedFile(File file) {
+        try {
+            byte[] buffer = new byte[8192];
+            ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+            GZIPInputStream gis = new GZIPInputStream(new FileInputStream(file));
+
+            int len;
+
+            while ( (len = gis.read(buffer, 0, 8192)) != -1) {
+                outputStream.write(buffer, 0, len);
+            }
+            gis.close();
+            return outputStream.toByteArray();
+        } catch (Exception e) {
+            Log.e(TAG, "failed to read compressed file " + file.toString() + " error: " + e.getMessage());
+            return null;
+        }
+    }
+
+    public static byte[] compressBitmapToByteArray(Bitmap bitmap) {
+        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
+        bitmap.compress(Bitmap.CompressFormat.PNG, 10, byteArrayOutputStream);
+        return byteArrayOutputStream.toByteArray();
+    }
+
+    public void saveSnapshot(String gameCode, String gameTitle, Bitmap previewImage, byte[] data) {
+        byte[] previewImageBytes = compressBitmapToByteArray(previewImage);
+
+        String hash = getHash(data);
+
+        File previewsDir = getPreviewsDir(gameCode);
+        File snapshotsDir = getSnapshotDir(gameCode);
+
+        File previewFile = new File(previewsDir, hash);
+        writeCompressedFile(previewFile, previewImageBytes);
+
+        File snapshotFile = new File(snapshotsDir, hash);
+        writeCompressedFile(snapshotFile, data);
+
+        this.dbHelper.insertSnapshot(gameCode, gameTitle, previewFile, snapshotFile);
+    }
+
+    public ArrayList<Snapshot> getAllSnapshots() {
+        return this.dbHelper.getAllEntries();
+    }
+
+    public ArrayList<Snapshot> getByGameCode(String gameCode) {
+        return this.dbHelper.getAllEntries(gameCode);
+    }
+}

AndroidApp/app/src/main/java/com/mrmichel/rustdroid_emu/ui/EmulatorActivity.java

@@ -1,25 +1,37 @@
 package com.mrmichel.rustdroid_emu.ui;
 
+import android.app.Activity;
 import android.content.DialogInterface;
 import android.content.Intent;
 import android.graphics.Bitmap;
 import android.net.Uri;
 import android.os.Bundle;
 
+import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.appcompat.app.AlertDialog;
 import androidx.appcompat.app.AppCompatActivity;
 
 import android.util.Log;
+import android.view.ContextMenu;
+import android.view.Menu;
+import android.view.MenuInflater;
+import android.view.MenuItem;
 import android.view.MotionEvent;
 import android.view.View;
+import android.view.WindowManager;
 import android.widget.ImageView;
-import android.widget.ToggleButton;
+import android.widget.Switch;
+import android.widget.Toast;
 
 import com.mrmichel.rustboyadvance.EmulatorBindings;
 import com.mrmichel.rustdroid_emu.core.Emulator;
 import com.mrmichel.rustdroid_emu.core.Keypad;
 import com.mrmichel.rustdroid_emu.R;
+import com.mrmichel.rustdroid_emu.core.Snapshot;
+import com.mrmichel.rustdroid_emu.core.SnapshotManager;
+import com.mrmichel.rustdroid_emu.ui.snapshots.ChosenSnapshot;
+import com.mrmichel.rustdroid_emu.ui.snapshots.SnapshotActivity;
 
 import java.io.File;
 import java.io.InputStream;
@@ -28,19 +40,20 @@ public class EmulatorActivity extends AppCompatActivity implements View.OnClickL
 
     private static final String TAG = "EmulatorActivty";
     private static final int LOAD_ROM_REQUESTCODE = 123;
+    private static final int LOAD_SNAPSHOT_REQUESTCODE = 124;
 
     private byte[] bios;
     private Emulator emulator = null;
     private EmulationRunnable runnable;
     private Thread emulationThread;
-    private byte[] snapshot = null;
+    private byte[] on_resume_saved_state = null;
     private ImageView screen;
     private boolean turboMode = false;
 
     @Override
     public void onClick(View v) {
         if (v.getId() == R.id.tbTurbo) {
-            ToggleButton tbTurbo = (ToggleButton) findViewById(R.id.tbTurbo);
+            Switch tbTurbo = (Switch) findViewById(R.id.tbTurbo);
             this.turboMode = tbTurbo.isChecked();
         }
     }
@@ -131,6 +144,16 @@ public class EmulatorActivity extends AppCompatActivity implements View.OnClickL
                     showAlertDiaglogAndExit(e);
                 }
             }
+            if (requestCode == LOAD_SNAPSHOT_REQUESTCODE) {
+                byte[] state = ChosenSnapshot.takeSnapshot().load();
+                if (emulator.isOpen()) {
+                    try {
+                        emulator.loadState(state);
+                    } catch (EmulatorBindings.NativeBindingException e) {
+                        showAlertDiaglogAndExit(e);
+                    }
+                }
+            }
         } else {
             Log.e(TAG, "got error for request code " + requestCode);
         }
@@ -187,11 +210,26 @@ public class EmulatorActivity extends AppCompatActivity implements View.OnClickL
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_emulator);
 
+        this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
+
+
         this.bios = getIntent().getByteArrayExtra("bios");
         this.screen = findViewById(R.id.gbaMockImageView);
         this.emulator = new Emulator();
     }
 
+    @Override
+    public boolean onCreateOptionsMenu(Menu menu) {
+        super.onCreateOptionsMenu(menu);
+        getMenuInflater().inflate(R.menu.menu_emulator, menu);
+        return true;
+    }
+
+    @Override
+    public boolean onOptionsItemSelected(@NonNull MenuItem item) {
+        return super.onOptionsItemSelected(item);
+    }
+
     @Override
     protected void onPause() {
         super.onPause();
@@ -200,31 +238,58 @@ public class EmulatorActivity extends AppCompatActivity implements View.OnClickL
                 runnable.pauseEmulation();
             }
             Log.d(TAG, "onPause - saving emulator state");
-            try {
+//            try {
-                snapshot = emulator.saveState();
+//                on_resume_saved_state = emulator.saveState();
-            } catch (EmulatorBindings.NativeBindingException e) {
+//            } catch (EmulatorBindings.NativeBindingException e) {
-                showAlertDiaglogAndExit(e);
+//                showAlertDiaglogAndExit(e);
-            }
+//            }
         }
     }
 
     @Override
     protected void onResume() {
         super.onResume();
-        if (emulator.isOpen() && snapshot != null) {
+        if (emulator.isOpen()) {
             Log.d(TAG, "onResume - loading emulator state");
-            try {
+//            try {
-                emulator.loadState(snapshot);
+//                emulator.loadState(on_resume_saved_state);
-            } catch (EmulatorBindings.NativeBindingException e) {
+//            } catch (EmulatorBindings.NativeBindingException e) {
-                showAlertDiaglogAndExit(e);
+//                showAlertDiaglogAndExit(e);
-            }
+//            }
-            snapshot = null;
+//            on_resume_saved_state = null;
             if (runnable != null) {
                 runnable.resumeEmulation();
             }
         }
     }
 
+    public void onSaveSnapshot(View v) {
+        SnapshotManager snapshotManager = SnapshotManager.getInstance(this);
+
+        runnable.pauseEmulation();
+        try {
+            String gameCode = emulator.getGameCode();
+            String gameTitle = emulator.getGameTitle();
+            byte[] saveState = emulator.saveState();
+            Bitmap preview = Bitmap.createBitmap(emulator.getFrameBuffer(), 240, 160, Bitmap.Config.RGB_565);
+
+            snapshotManager.saveSnapshot(gameCode, gameTitle, preview, saveState);
+            Toast.makeText(this, "Snapshot saved", Toast.LENGTH_LONG).show();
+
+        } catch (EmulatorBindings.NativeBindingException e) {
+            Log.e(TAG, e.toString());
+            showAlertDiaglogAndExit(e);
+        } finally {
+            runnable.resumeEmulation();
+        }
+    }
+
+
+    public void onViewSnapshots(View v) {
+        Intent intent = new Intent(this, SnapshotActivity.class);
+        startActivityForResult(intent, LOAD_SNAPSHOT_REQUESTCODE);
+    }
+
     public void updateScreen(Bitmap bmp) {
         this.screen.setImageBitmap(bmp);
     }
@@ -247,19 +312,7 @@ public class EmulatorActivity extends AppCompatActivity implements View.OnClickL
 
         private void emulate() {
             long startTimer = System.nanoTime();
-
+            emulator.runFrame();
-            try {
-                emulator.runFrame();
-            } catch (final EmulatorBindings.NativeBindingException e) {
-                this.running = false;
-                emulatorActivity.runOnUiThread(new Runnable() {
-                    @Override
-                    public void run() {
-                        showAlertDiaglogAndExit(e);
-                    }
-                });
-            }
-
             if (!emulatorActivity.turboMode) {
                 long currentTime = System.nanoTime();
                 long timePassed = currentTime - startTimer;

AndroidApp/app/src/main/java/com/mrmichel/rustdroid_emu/ui/RomListActivity.java

@@ -0,0 +1,32 @@
+package com.mrmichel.rustdroid_emu.ui;
+
+import android.os.Bundle;
+
+import com.google.android.material.floatingactionbutton.FloatingActionButton;
+import com.google.android.material.snackbar.Snackbar;
+import com.mrmichel.rustdroid_emu.R;
+
+import androidx.appcompat.app.AppCompatActivity;
+import androidx.appcompat.widget.Toolbar;
+
+import android.view.View;
+
+public class RomListActivity extends AppCompatActivity {
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.activity_rom_list);
+        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
+        setSupportActionBar(toolbar);
+
+        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
+        fab.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View view) {
+                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
+                        .setAction("Action", null).show();
+            }
+        });
+    }
+}

AndroidApp/app/src/main/java/com/mrmichel/rustdroid_emu/ui/SplashActivity.java

@@ -46,7 +46,7 @@ public class SplashActivity extends AppCompatActivity {
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
-        setContentView(R.layout.main_activity);
+        setContentView(R.layout.splash_activity);
 
         if (ContextCompat.checkSelfPermission(this,
                 Manifest.permission.WRITE_EXTERNAL_STORAGE)

AndroidApp/app/src/main/java/com/mrmichel/rustdroid_emu/ui/snapshots/ChosenSnapshot.java

@@ -0,0 +1,21 @@
+package com.mrmichel.rustdroid_emu.ui.snapshots;
+
+import com.mrmichel.rustdroid_emu.core.Snapshot;
+
+/**
+ * static class to transfer big byte arrays between activities
+ */
+public class ChosenSnapshot {
+
+    static Snapshot snapshot;
+
+    public static void setSnapshot(Snapshot snapshot) {
+        ChosenSnapshot.snapshot = snapshot;
+    }
+
+    public static Snapshot takeSnapshot() {
+        Snapshot result = ChosenSnapshot.snapshot;
+        ChosenSnapshot.snapshot = null;
+        return result;
+    }
+}

AndroidApp/app/src/main/java/com/mrmichel/rustdroid_emu/ui/snapshots/SnapshotActivity.java

@@ -0,0 +1,69 @@
+package com.mrmichel.rustdroid_emu.ui.snapshots;
+
+import android.app.Activity;
+import android.content.DialogInterface;
+import android.content.Intent;
+import android.net.Uri;
+import android.os.Bundle;
+
+import com.google.android.material.floatingactionbutton.FloatingActionButton;
+import com.google.android.material.snackbar.Snackbar;
+
+import androidx.appcompat.app.AlertDialog;
+import androidx.appcompat.app.AppCompatActivity;
+import androidx.appcompat.widget.Toolbar;
+
+import android.view.View;
+import android.widget.AdapterView;
+import android.widget.GridView;
+import android.widget.ListView;
+import android.widget.Toast;
+
+import com.mrmichel.rustdroid_emu.R;
+import com.mrmichel.rustdroid_emu.core.Snapshot;
+import com.mrmichel.rustdroid_emu.core.SnapshotManager;
+
+import java.util.ArrayList;
+
+public class SnapshotActivity extends AppCompatActivity {
+
+    private ArrayList<Snapshot> snapshots;
+    public static final String EXTRA_GAME_CODE = "GAME_CODE";
+
+    public void onChosenSnapshot(Snapshot snapshot) {
+        Toast.makeText(this, "loading snapshot", Toast.LENGTH_SHORT).show();
+        Intent intent = new Intent();
+        setResult(RESULT_OK, intent);
+        ChosenSnapshot.setSnapshot(snapshot);
+        SnapshotActivity.this.finish();
+    }
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.activity_snapshot);
+
+        SnapshotManager manager = SnapshotManager.getInstance(this);
+
+        String gameCode = getIntent().getStringExtra(EXTRA_GAME_CODE);
+
+        if (gameCode == null) {
+            snapshots = manager.getAllSnapshots();
+        } else {
+            snapshots = manager.getByGameCode(gameCode);
+        }
+
+        SnapshotItemAdapter adapter = new SnapshotItemAdapter(this, snapshots);
+
+        GridView view = findViewById(R.id.gridview_snapshots);
+        view.setAdapter(adapter);
+        view.setOnItemClickListener(new AdapterView.OnItemClickListener() {
+            @Override
+            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
+                final Snapshot snapshot = snapshots.get(position);
+                onChosenSnapshot(snapshot);
+            }
+        });
+    }
+}
+

AndroidApp/app/src/main/java/com/mrmichel/rustdroid_emu/ui/snapshots/SnapshotItemAdapter.java

@@ -0,0 +1,66 @@
+package com.mrmichel.rustdroid_emu.ui.snapshots;
+
+import android.content.Context;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.ArrayAdapter;
+import android.widget.ImageButton;
+import android.widget.ImageView;
+import android.widget.TextView;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+import com.mrmichel.rustdroid_emu.R;
+import com.mrmichel.rustdroid_emu.core.Snapshot;
+
+import org.w3c.dom.Text;
+
+import java.sql.Timestamp;
+import java.util.ArrayList;
+
+public class SnapshotItemAdapter extends ArrayAdapter<Snapshot> {
+
+    Context context;
+    ArrayList<Snapshot> items;
+
+    public SnapshotItemAdapter(Context context, ArrayList<Snapshot> items) {
+        super(context, 0, items);
+        this.context = context;
+        this.items = items;
+    }
+
+    @Override
+    public int getCount() {
+        return items.size();
+    }
+
+    @Override
+    public long getItemId(int position) {
+        return 0;
+    }
+
+    @NonNull
+    @Override
+    public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
+        Snapshot snapshot = getItem(position);
+
+        if (convertView == null) {
+            convertView = LayoutInflater.from(getContext()).inflate(R.layout.snapshot_item, parent, false);
+        }
+
+        ImageView preview = (ImageView) convertView.findViewById(R.id.imageview_snapshot_preview);
+        preview.setImageBitmap(snapshot.getPreview());
+
+
+        TextView tvTitle = (TextView) convertView.findViewById(R.id.textview_snapshot_title);
+        tvTitle.setText(snapshot.getGameTitle());
+
+        TextView tvTimestamp = (TextView) convertView.findViewById(R.id.textview_snapshot_timestmap);
+        Timestamp timestamp = new Timestamp(snapshot.getTimestamp());
+        tvTimestamp.setText(timestamp.toString());
+
+        return convertView;
+    }
+}

AndroidApp/app/src/main/res/layout/activity_emulator.xml

@@ -6,18 +6,31 @@
     android:layout_height="match_parent"
     tools:context=".ui.EmulatorActivity">
 
+
     <com.google.android.material.appbar.AppBarLayout
+        android:id="@+id/app_bar"
         android:layout_width="match_parent"
-        android:layout_height="wrap_content"
+        android:layout_height="@dimen/app_bar_height"
+        android:fitsSystemWindows="true"
         android:theme="@style/AppTheme.AppBarOverlay">
 
-<!--        <androidx.appcompat.widget.Toolbar-->
+        <com.google.android.material.appbar.CollapsingToolbarLayout
-<!--            android:id="@+id/toolbar"-->
+            android:id="@+id/toolbar_layout"
-<!--            android:layout_width="match_parent"-->
+            android:layout_width="match_parent"
-<!--            android:layout_height="?attr/actionBarSize"-->
+            android:layout_height="match_parent"
-<!--            android:background="?attr/colorPrimary"-->
+            android:fitsSystemWindows="true"
-<!--            app:popupTheme="@style/AppTheme.PopupOverlay" />-->
+            app:contentScrim="?attr/colorPrimary"
+            app:layout_scrollFlags="scroll|exitUntilCollapsed"
+            app:toolbarId="@+id/toolbar">
 
+            <androidx.appcompat.widget.Toolbar
+                android:id="@+id/toolbar"
+                android:layout_width="match_parent"
+                android:layout_height="?attr/actionBarSize"
+                app:layout_collapseMode="pin"
+                app:popupTheme="@style/AppTheme.PopupOverlay" />
+
+        </com.google.android.material.appbar.CollapsingToolbarLayout>
     </com.google.android.material.appbar.AppBarLayout>
 
     <include layout="@layout/content_emulator" />

AndroidApp/app/src/main/res/layout/activity_rom_list.xml

@@ -0,0 +1,47 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.coordinatorlayout.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:fitsSystemWindows="true"
+    tools:context=".ui.RomListActivity">
+
+    <com.google.android.material.appbar.AppBarLayout
+        android:id="@+id/app_bar"
+        android:layout_width="match_parent"
+        android:layout_height="@dimen/app_bar_height"
+        android:fitsSystemWindows="true"
+        android:theme="@style/AppTheme.AppBarOverlay">
+
+        <com.google.android.material.appbar.CollapsingToolbarLayout
+            android:id="@+id/toolbar_layout"
+            android:layout_width="match_parent"
+            android:layout_height="match_parent"
+            android:fitsSystemWindows="true"
+            app:contentScrim="?attr/colorPrimary"
+            app:layout_scrollFlags="scroll|exitUntilCollapsed"
+            app:toolbarId="@+id/toolbar">
+
+            <androidx.appcompat.widget.Toolbar
+                android:id="@+id/toolbar"
+                android:layout_width="match_parent"
+                android:layout_height="?attr/actionBarSize"
+                app:layout_collapseMode="pin"
+                app:popupTheme="@style/AppTheme.PopupOverlay" />
+
+        </com.google.android.material.appbar.CollapsingToolbarLayout>
+    </com.google.android.material.appbar.AppBarLayout>
+
+    <include layout="@layout/content_rom_list" />
+
+    <com.google.android.material.floatingactionbutton.FloatingActionButton
+        android:id="@+id/fab"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_margin="@dimen/fab_margin"
+        app:layout_anchor="@id/app_bar"
+        app:layout_anchorGravity="bottom|end"
+        app:srcCompat="@android:drawable/ic_dialog_email" />
+
+</androidx.coordinatorlayout.widget.CoordinatorLayout>

AndroidApp/app/src/main/res/layout/activity_snapshot.xml

@@ -0,0 +1,59 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:background="#6c45c0"
+    tools:context=".ui.snapshots.SnapshotActivity">
+
+
+    <TextView
+        android:id="@+id/textView"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_marginStart="126dp"
+        android:layout_marginTop="8dp"
+        android:layout_marginEnd="126dp"
+        android:gravity="center"
+        android:text="Choose snapshot to load"
+        android:textAppearance="@style/TextAppearance.AppCompat.Display1"
+        android:textSize="14sp"
+        android:textStyle="bold"
+        android:typeface="monospace"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/edittext_snapshot_filter" />
+
+    <EditText
+        android:id="@+id/edittext_snapshot_filter"
+        style="@style/Widget.AppCompat.EditText"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_marginStart="16dp"
+        android:layout_marginTop="16dp"
+        android:ems="10"
+        android:hint="Search.."
+        android:inputType="textFilter|textPersonName"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent" />
+
+    <GridView
+        android:id="@+id/gridview_snapshots"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_marginStart="8dp"
+        android:layout_marginTop="16dp"
+        android:layout_marginEnd="8dp"
+        android:gravity="center"
+        android:numColumns="auto_fit"
+        app:layout_behavior="@string/appbar_scrolling_view_behavior"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/textView"
+        tools:context=".ui.snapshots.SnapshotActivity"
+        tools:showIn="@layout/activity_snapshot">
+
+    </GridView>
+
+</androidx.constraintlayout.widget.ConstraintLayout>

AndroidApp/app/src/main/res/layout/content_emulator.xml

@@ -28,7 +28,7 @@
         app:layout_constraintEnd_toEndOf="parent"
         app:layout_constraintHorizontal_bias="0.517"
         app:layout_constraintStart_toStartOf="parent"
-        app:layout_constraintTop_toBottomOf="@+id/bSave" />
+        app:layout_constraintTop_toBottomOf="@+id/bSnapshotSave" />
 
     <Button
         android:id="@+id/buttonB"
@@ -129,26 +129,32 @@
         app:layout_constraintTop_toTopOf="parent" />
 
     <Button
-        android:id="@+id/bSave"
+        android:id="@+id/bSnapshotSave"
+        style="@style/Widget.AppCompat.Button.Small"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_marginTop="16dp"
-        android:layout_marginEnd="32dp"
+        android:layout_marginEnd="4dp"
-        android:text="Save"
+        android:onClick="onSaveSnapshot"
+        android:text="@string/action_save_snapshot"
         app:layout_constraintEnd_toStartOf="@+id/bRestore"
+        app:layout_constraintStart_toEndOf="@+id/bLoadRom"
         app:layout_constraintTop_toTopOf="parent" />
 
     <Button
         android:id="@+id/bRestore"
+        style="@style/Widget.AppCompat.Button.Small"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_marginTop="16dp"
         android:layout_marginEnd="16dp"
         android:layout_marginBottom="12dp"
-        android:text="Button"
+        android:onClick="onViewSnapshots"
+        android:text="@string/action_view_snapshot"
         app:layout_constraintBottom_toTopOf="@+id/gbaMockImageView"
         app:layout_constraintEnd_toEndOf="parent"
-        app:layout_constraintTop_toTopOf="parent" />
+        app:layout_constraintTop_toTopOf="parent"
+        app:layout_constraintVertical_bias="0.0" />
 
     <TextView
         android:id="@+id/tvFPS"

AndroidApp/app/src/main/res/layout/content_rom_list.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.core.widget.NestedScrollView xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    app:layout_behavior="@string/appbar_scrolling_view_behavior"
+    tools:context=".ui.RomListActivity"
+    tools:showIn="@layout/activity_rom_list">
+
+    <TextView
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_margin="@dimen/text_margin"
+        android:text="@string/large_text" />
+
+</androidx.core.widget.NestedScrollView>

AndroidApp/app/src/main/res/layout/snapshot_item.xml

@@ -0,0 +1,38 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    android:orientation="vertical"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:gravity="center"
+    >
+
+    <ImageView
+        android:id="@+id/imageview_snapshot_preview"
+        android:layout_width="180dp"
+        android:layout_height="160dp"
+        android:scaleType="centerCrop"
+        app:srcCompat="@drawable/icon" />
+
+    <TextView
+        android:id="@+id/textview_snapshot_title"
+        android:layout_width="180dp"
+        android:layout_height="wrap_content"
+        android:text="Cool Game - III"
+        android:gravity="center_horizontal"
+        android:paddingTop="4dp"
+        android:paddingLeft="8dp"
+        android:paddingRight="8dp"
+        android:textStyle="bold"
+        android:textSize="12sp"
+        android:textAppearance="@style/TextAppearance.AppCompat.Medium" />
+    <TextView
+        android:id="@+id/textview_snapshot_timestmap"
+        android:layout_width="180dp"
+        android:layout_height="wrap_content"
+        android:text="1.1.2020"
+        android:gravity="center_horizontal"
+        android:textSize="12sp"
+        />
+
+</LinearLayout>

AndroidApp/app/src/main/res/menu/menu_emulator.xml

@@ -0,0 +1,20 @@
+<menu xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    tools:context="com.mrmichel.rustdroid_emu.ui.RomListActivity">
+    <item
+        android:id="@+id/action_settings"
+        android:orderInCategory="100"
+        android:title="@string/action_settings"
+        app:showAsAction="never" />
+    <item
+        android:id="@+id/action_save_snapshot"
+        android:icon="@android:drawable/ic_input_add"
+        android:orderInCategory="101"
+        android:title="@string/action_save_snapshot"
+        app:showAsAction="withText" />
+    <item
+        android:id="@+id/action_view_snapshots"
+        android:orderInCategory="102"
+        android:title="@string/action_view_snapshot" />
+</menu>

AndroidApp/app/src/main/res/menu/menu_rom_list.xml

@@ -0,0 +1,10 @@
+<menu xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    tools:context="com.mrmichel.rustdroid_emu.ui.RomListActivity">
+    <item
+        android:id="@+id/action_settings"
+        android:orderInCategory="100"
+        android:title="@string/action_settings"
+        app:showAsAction="never" />
+</menu>

AndroidApp/app/src/main/res/menu/menu_snapshot.xml

@@ -0,0 +1,10 @@
+<menu xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    tools:context="com.mrmichel.rustdroid_emu.ui.snapshots.SnapshotActivity">
+    <item
+        android:id="@+id/action_settings"
+        android:orderInCategory="100"
+        android:title="@string/action_settings"
+        app:showAsAction="never" />
+</menu>

AndroidApp/app/src/main/res/values/dimens.xml

@@ -1,3 +1,5 @@
 <resources>
     <dimen name="fab_margin">16dp</dimen>
+    <dimen name="app_bar_height">180dp</dimen>
+    <dimen name="text_margin">16dp</dimen>
 </resources>

AndroidApp/app/src/main/res/values/strings.xml

@@ -1,4 +1,99 @@
 <resources>
     <string name="app_name">RustdroidAdvance</string>
     <string name="title_activity_emulator">RustdroidAdvance</string>
+    <string name="title_activity_rom_list">Roms</string>
+    <string name="large_text">
+        "Material is the metaphor.\n\n"
+
+        "A material metaphor is the unifying theory of a rationalized space and a system of motion."
+        "The material is grounded in tactile reality, inspired by the study of paper and ink, yet "
+        "technologically advanced and open to imagination and magic.\n"
+        "Surfaces and edges of the material provide visual cues that are grounded in reality. The "
+        "use of familiar tactile attributes helps users quickly understand affordances. Yet the "
+        "flexibility of the material creates new affordances that supercede those in the physical "
+        "world, without breaking the rules of physics.\n"
+        "The fundamentals of light, surface, and movement are key to conveying how objects move, "
+        "interact, and exist in space and in relation to each other. Realistic lighting shows "
+        "seams, divides space, and indicates moving parts.\n\n"
+
+        "Bold, graphic, intentional.\n\n"
+
+        "The foundational elements of print based design typography, grids, space, scale, color, "
+        "and use of imagery guide visual treatments. These elements do far more than please the "
+        "eye. They create hierarchy, meaning, and focus. Deliberate color choices, edge to edge "
+        "imagery, large scale typography, and intentional white space create a bold and graphic "
+        "interface that immerse the user in the experience.\n"
+        "An emphasis on user actions makes core functionality immediately apparent and provides "
+        "waypoints for the user.\n\n"
+
+        "Motion provides meaning.\n\n"
+
+        "Motion respects and reinforces the user as the prime mover. Primary user actions are "
+        "inflection points that initiate motion, transforming the whole design.\n"
+        "All action takes place in a single environment. Objects are presented to the user without "
+        "breaking the continuity of experience even as they transform and reorganize.\n"
+        "Motion is meaningful and appropriate, serving to focus attention and maintain continuity. "
+        "Feedback is subtle yet clear. Transitions are efficient yet coherent.\n\n"
+
+        "3D world.\n\n"
+
+        "The material environment is a 3D space, which means all objects have x, y, and z "
+        "dimensions. The z-axis is perpendicularly aligned to the plane of the display, with the "
+        "positive z-axis extending towards the viewer. Every sheet of material occupies a single "
+        "position along the z-axis and has a standard 1dp thickness.\n"
+        "On the web, the z-axis is used for layering and not for perspective. The 3D world is "
+        "emulated by manipulating the y-axis.\n\n"
+
+        "Light and shadow.\n\n"
+
+        "Within the material environment, virtual lights illuminate the scene. Key lights create "
+        "directional shadows, while ambient light creates soft shadows from all angles.\n"
+        "Shadows in the material environment are cast by these two light sources. In Android "
+        "development, shadows occur when light sources are blocked by sheets of material at "
+        "various positions along the z-axis. On the web, shadows are depicted by manipulating the "
+        "y-axis only. The following example shows the card with a height of 6dp.\n\n"
+
+        "Resting elevation.\n\n"
+
+        "All material objects, regardless of size, have a resting elevation, or default elevation "
+        "that does not change. If an object changes elevation, it should return to its resting "
+        "elevation as soon as possible.\n\n"
+
+        "Component elevations.\n\n"
+
+        "The resting elevation for a component type is consistent across apps (e.g., FAB elevation "
+        "does not vary from 6dp in one app to 16dp in another app).\n"
+        "Components may have different resting elevations across platforms, depending on the depth "
+        "of the environment (e.g., TV has a greater depth than mobile or desktop).\n\n"
+
+        "Responsive elevation and dynamic elevation offsets.\n\n"
+
+        "Some component types have responsive elevation, meaning they change elevation in response "
+        "to user input (e.g., normal, focused, and pressed) or system events. These elevation "
+        "changes are consistently implemented using dynamic elevation offsets.\n"
+        "Dynamic elevation offsets are the goal elevation that a component moves towards, relative "
+        "to the component’s resting state. They ensure that elevation changes are consistent "
+        "across actions and component types. For example, all components that lift on press have "
+        "the same elevation change relative to their resting elevation.\n"
+        "Once the input event is completed or cancelled, the component will return to its resting "
+        "elevation.\n\n"
+
+        "Avoiding elevation interference.\n\n"
+
+        "Components with responsive elevations may encounter other components as they move between "
+        "their resting elevations and dynamic elevation offsets. Because material cannot pass "
+        "through other material, components avoid interfering with one another any number of ways, "
+        "whether on a per component basis or using the entire app layout.\n"
+        "On a component level, components can move or be removed before they cause interference. "
+        "For example, a floating action button (FAB) can disappear or move off screen before a "
+        "user picks up a card, or it can move if a snackbar appears.\n"
+        "On the layout level, design your app layout to minimize opportunities for interference. "
+        "For example, position the FAB to one side of stream of a cards so the FAB won’t interfere "
+        "when a user tries to pick up one of cards.\n\n"
+    </string>
+    <string name="action_settings">Settings</string>
+    <string name="action_save_snapshot">Save Snapshot</string>
+    <string name="action_view_snapshot">View Snapshots</string>
+
+    <string name="title_activity_snapshot">Snapshot Manager</string>
 </resources>