应用程序打开时黑屏

Question

I keep getting this black screen when ever I open my app, the only way to get rid of it is to press the back button, then again go to the app. I was told by my friend that it is going into deadlock. but I do not think because when I checked the logcat it shows the below log messages.

View

private boolean mGameIsRunning;

public void surfaceCreated(SurfaceHolder holder) {
    // Your own start method.
    start();

}

public void start() {
    if (!mGameIsRunning) {
        thread.initLevel();
        thread.setRunning(true);
        thread.start();   

        mGameIsRunning = true;
    } else {

        thread.onResume();

        thread.initLevel();
        thread.setRunning(true);
    }
}

public void surfaceDestroyed(SurfaceHolder holder) {
    Log.d(TAG, "Surface is being destroyed");

    // tell the thread to shut down and wait for it to finish
    // this is a clean shutdown
    boolean retry = true;
    thread.setRunning(false);       
    while (retry) {     
        try {
            thread.join();
            retry = false;  
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }           
    }
    Log.d(TAG, "Thread was shut down cleanly"); 
}

Thread

private Object mPauseLock = new Object();  
    private boolean mPaused;
    @Override
    public void run() {
        Canvas canvas;
        Log.d(TAG, "Starting game loop");
        while (running) {
            canvas = null;
            // try locking the canvas for exclusive pixel editing
            // in the surface
            try {
                canvas = this.mSurfaceHolder.lockCanvas();
                synchronized (mSurfaceHolder) {
                    mStartTime = System.currentTimeMillis();
                    mElapsedTime = System.currentTimeMillis() - mStartTime;

                    this.updateGame();
                    this.onDraw(canvas);
                }

                synchronized(mPauseLock){
                    while (mPaused) {

                        try {
                            mPauseLock.wait();
                        } catch (InterruptedException e) {
                        }
                    }   

                }

            } finally {
                // in case of an exception the surface is not left in
                // an inconsistent state
                if (canvas != null) {
                    mSurfaceHolder.unlockCanvasAndPost(canvas);
                }
            }   // end finally          
        }       
    }
    public void onPause() {
        synchronized (mPauseLock) {
            mPaused = true;         
        }
    }

    public void onResume() {
        synchronized (mPauseLock) {
            mPaused = false;
            mPauseLock.notifyAll();
        }
    }

Log

07-08 17:24:41.735: DEBUG/Hitman(3221): View added
07-08 17:24:41.895: DEBUG/(3221): Enemies Spawed
07-08 17:24:41.934: DEBUG/(3221): Starting game loop
07-08 17:24:42.165: INFO/ActivityManager(66): Displayed activity com.android.hitmanassault/.Hitman: 1384 ms (total 1384 ms)
07-08 17:24:46.164: DEBUG/(3221): Enemies Spawed
07-08 17:24:48.914: INFO/ActivityManager(66): Start proc com.android.settings for broadcast com.android.settings/.widget.SettingsAppWidgetProvider: pid=3228 uid=1000 gids={3002, 3001, 3003}
07-08 17:24:48.914: INFO/ActivityManager(66): Starting activity: Intent { act=android.intent.action.MAIN cat=[android.intent.category.HOME] flg=0x10200000 cmp=com.android.launcher/.Launcher }
07-08 17:24:48.924: DEBUG/PhoneWindow(3221): couldn't save which view has focus because the focused view com.android.hitmanassault.HitmanView@44d99528 has no id.
07-08 17:24:48.954: INFO/WindowManager(66): Setting rotation to 0, animFlags=0
07-08 17:24:49.014: INFO/ActivityManager(66): Config changed: { scale=1.0 imsi=310/260 loc=en_US touch=3 keys=2/1/2 nav=3/1 orien=1 layout=34}
07-08 17:24:49.275: DEBUG/(3221): Surface is being destroyed
07-08 17:24:49.285: DEBUG/(3221): Thread was shut down cleanly
07-08 17:24:49.694: DEBUG/ddm-heap(3228): Got feature list request
07-08 17:24:49.754: WARN/IInputConnectionWrapper(3221): showStatusIcon on inactive InputConnection
07-08 17:24:51.315: DEBUG/dalvikvm(66): GC freed 2325 objects / 114696 bytes in 122ms
07-08 17:24:58.234: INFO/ActivityManager(66): Starting activity: Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.android.hitmanassault/.HitmanTitle }
07-08 17:24:58.284: INFO/WindowManager(66): Setting rotation to 1, animFlags=0
07-08 17:24:58.354: INFO/ActivityManager(66): Config changed: { scale=1.0 imsi=310/260 loc=en_US touch=3 keys=2/1/2 nav=3/1 orien=2 layout=34}
07-08 17:24:58.554: DEBUG/(3221): Enemies Spawed
07-08 17:24:58.945: WARN/IInputConnectionWrapper(144): showStatusIcon on inactive InputConnection
07-08 17:25:00.604: DEBUG/dalvikvm(66): GC freed 1403 objects / 71832 bytes in 103ms

Activity Class:

@Override
    public boolean onCreateOptionsMenu(Menu menu){
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.game_menu, menu);
        return true;
    }

@Override
public boolean onOptionsItemSelected(MenuItem item){

    switch(item.getItemId()){
    case R.id.menu_restart:
        startActivity(new Intent(this, Hitman.class));
        return true;
    case R.id.menu_scores:
        startActivity(new Intent(this, HitmanScores.class));
        return true;
    case R.id.menu_help:
        startActivity(new Intent(this, HitmanHelp.class));
        return true;
    default:
        return super.onOptionsItemSelected(item);
    }
}

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);   
    setContentView(new CanvasSurfaceView(this));
    Log.d(TAG, "View added");   

}

Answer 1

Does rotating the display cause it to refresh (in emulator: CTRL+F12)? If so then you have to override onResume() in your activity and have it restart whatever it is you set up that might not be being called. It could be that you just need to call view.invalidate() from the activity onResume()? You don't show code from your activity so I'm unsure.

In the code I saw, you should use this.postInvalidate() (same as invalidate() but for from a different thread) instead of this.onDraw(canvas) and have it call this.onDraw() on its own in the UI thread, as opposed to in your thread.

Answer 2

Where do you initialize your thread? Try doing so in surfaceCreated( ) instead of the surfaceView consturctor (which is where I think you did it..)

public void surfaceCreated(SurfaceHolder holder) { 

    // Restart draw thread
    Thread.State state = thread.getState();

    if(state == Thread.State.TERMINATED)
        thread = new MyThread(getHolder(), getContext());   
    thread.setRunning(true);
    thread.start();  

}