I have a very simple game SurfaceView and sometimes game does not responde to touch events for a few seconds, then it respondes to the all of those touch events at once. I have tested my game on Galaxy S3 and Nexus 4 and it works fine, it seems this problem only occurs on Galaxy S5.
Main Activity:
public class DroidzActivity extends Activity {
/** Called when the activity is first created. */
private static final String TAG = DroidzActivity.class.getSimpleName();
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// requesting to turn the title OFF
requestWindowFeature(Window.FEATURE_NO_TITLE);
// making it full screen
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
// set our MainGamePanel as the View
setContentView(new MainGamePanel(this));
Log.d(TAG, "View added");
}
@Override
protected void onDestroy() {
Log.d(TAG, "Destroying...");
super.onDestroy();
}
@Override
protected void onStop() {
Log.d(TAG, "Stopping...");
super.onStop();
}
}
public class MainGamePanel extends SurfaceView implements SurfaceHolder.Callback {
private static final String TAG = MainGamePanel.class.getSimpleName();
private MainThread thread;
public MainGamePanel(Context context) {
super(context);
// adding the callback (this) to the surface holder to intercept events
getHolder().addCallback(this);
// create the game loop thread
thread = new MainThread(getHolder(), this);
// make the GamePanel focusable so it can handle events
setFocusable(true);
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
// at this point the surface is created and
// we can safely start the game loop
thread.setRunning(true);
thread.start();
}
@Override
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;
while (retry) {
try {
thread.setRunning(false);
thread.join();
retry = false;
} catch (InterruptedException e) {
// try again shutting down the thread
}
}
Log.d(TAG, "Thread was shut down cleanly");
}
public void render(Canvas canvas){
if(canvas!=null)
canvas.drawColor(colorList[colorIndex]);
}
@Override
public boolean onTouchEvent(MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_DOWN) {
colorIndex++;
colorIndex = colorIndex % colorList.length;
}
return super.onTouchEvent(event);
}
int [] colorList = {Color.RED, Color.GREEN, Color.BLUE, Color.GRAY};
int colorIndex = 0;
}
MainThread
public class MainThread extends Thread {
private static final String TAG = MainThread.class.getSimpleName();
// Surface holder that can access the physical surface
private SurfaceHolder surfaceHolder;
// The actual view that handles inputs
// and draws to the surface
private MainGamePanel gamePanel;
// flag to hold game state
private boolean running;
public void setRunning(boolean running) {
this.running = running;
}
public MainThread(SurfaceHolder surfaceHolder, MainGamePanel gamePanel) {
super();
this.surfaceHolder = surfaceHolder;
this.gamePanel = gamePanel;
}
// desired fps
private final static int MAX_FPS = 50;
// maximum number of frames to be skipped
private final static int MAX_FRAME_SKIPS = 5;
// the frame period
private final static int FRAME_PERIOD = 1000 / MAX_FPS;
@Override
public void run() {
Canvas canvas;
Log.d(TAG, "Starting game loop");
long beginTime; // the time when the cycle begun
long timeDiff; // the time it took for the cycle to execute
int sleepTime; // ms to sleep (<0 if we're behind)
int framesSkipped; // number of frames being skipped
sleepTime = 0;
while (running) {
canvas = null;
// try locking the canvas for exclusive pixel editing
// in the surface
try {
canvas = this.surfaceHolder.lockCanvas();
synchronized (surfaceHolder) {
beginTime = System.currentTimeMillis();
framesSkipped = 0; // resetting the frames skipped
// update game state
// this.gamePanel.update();
// render state to the screen
// draws the canvas on the panel
this.gamePanel.render(canvas);
// calculate how long did the cycle take
timeDiff = System.currentTimeMillis() - beginTime;
// calculate sleep time
sleepTime = (int)(FRAME_PERIOD - timeDiff);
if (sleepTime > 0) {
// if sleepTime > 0 we're OK
try {
// send the thread to sleep for a short period
// very useful for battery saving
Thread.sleep(sleepTime);
} catch (InterruptedException e) {}
}
while (sleepTime < 0 && framesSkipped < MAX_FRAME_SKIPS) {
// we need to catch up
// update without rendering
// this.gamePanel.update();
// add frame period to check if in next frame
sleepTime += FRAME_PERIOD;
framesSkipped++;
}
}
} finally {
// in case of an exception the surface is not left in
// an inconsistent state
if (canvas != null) {
surfaceHolder.unlockCanvasAndPost(canvas);
}
} // end finally
}
}
}
Here is the most simple version of the app, I have tried and I have able to recreate same problem again. It also sometimes takes 5-10 seconds to load on S5 while it loads less then 1 second on Nexus 4 and S3.
It looks like MainThread is starving the UI thread.
The code that ends up executing (with a lot of stuff removed) looks like:
canvas = this.surfaceHolder.lockCanvas();
// Do a ton of stuff
surfaceHolder.unlockCanvasAndPost(canvas);
canvas = this.surfaceHolder.lockCanvas();
// Do a ton of stuff
surfaceHolder.unlockCanvasAndPost(canvas);
canvas = this.surfaceHolder.lockCanvas();
// Do a ton of stuff
surfaceHolder.unlockCanvasAndPost(canvas);
This is supported by the android source. Note that SurfaceHolder#lock calls mSurfaceLock.lock(). This is also called in SurfaceHolder#updateWindow, which is called in a variety of other places in that file.
mSurfaceLock is a ReentrantLock, and the documentation states:
The constructor for this class accepts an optional fairness parameter. When set true, under contention, locks favor granting access to the longest-waiting thread. Otherwise this lock does not guarantee any particular access order.
SurfaceView doesn't specify fairness, so it should be using the default, which can lead to exactly this starvation.
Try moving some of your work and particularly the sleeps outside the lock/unlock calls.