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POAndroid app not responding when closed
 

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  1. POAndroid app not responding when closed
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    <p>I am working on an game for android, and when I close the app it crashes. I think this is because I am doing a render with a null canvas. When I do a null check, the program doesn't crash, but it doesn't reopen after it has been closed. Here is my thread's run:</p> <pre><code>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 (&lt;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 &gt; 0) { // if sleepTime &gt; 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 &lt; 0 &amp;&amp; framesSkipped &lt; MAX_FRAME_SKIPS) { // we need to catch up this.gamePanel.update(); // update without rendering sleepTime += FRAME_PERIOD; // add frame period to check if in next frame framesSkipped++; } } } finally { // in case of an exception the surface is not left in // an inconsistent state if (canvas != null) { surfaceHolder.unlockCanvasAndPost(canvas); } } // end finally } } </code></pre> <p>and here are the relavent methods in the surface class.</p> <pre><code> @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"); } </code></pre> <p>Is the null check correct and I am just missing the methods to resume the activity?</p> <p>Logcat when nullcheck isn't in place:</p> <pre><code>03-01 10:37:19.557: E/AndroidRuntime(25129): FATAL EXCEPTION: Thread-16380 03-01 10:37:19.557: E/AndroidRuntime(25129): java.lang.NullPointerException 03-01 10:37:19.557: E/AndroidRuntime(25129): at org.awesome.AndroidGame.MainGamePanel.render(MainGamePanel.java:192) 03-01 10:37:19.557: E/AndroidRuntime(25129): at org.awesome.AndroidGame.MainThread.run(MainThread.java:73) 03-01 10:37:23.357: E/BitmapFactory(25280): Unable to decode stream: java.io.FileNotFoundException: /level_1_1.png: open failed: ENOENT (No such file or directory) 03-01 10:37:36.097: E/AndroidRuntime(25280): FATAL EXCEPTION: Thread-16395 03-01 10:37:36.097: E/AndroidRuntime(25280): java.lang.NullPointerException 03-01 10:37:36.097: E/AndroidRuntime(25280): at org.awesome.AndroidGame.MainGamePanel.render(MainGamePanel.java:192) 03-01 10:37:36.097: E/AndroidRuntime(25280): at org.awesome.AndroidGame.MainThread.run(MainThread.java:73) 03-01 11:02:49.227: E/AndroidRuntime(26150): FATAL EXCEPTION: Thread-16425 03-01 11:02:49.227: E/AndroidRuntime(26150): java.lang.NullPointerException 03-01 11:02:49.227: E/AndroidRuntime(26150): at org.awesome.AndroidGame.MainGamePanel.render(MainGamePanel.java:192) 03-01 11:02:49.227: E/AndroidRuntime(26150): at org.awesome.AndroidGame.MainThread.run(MainThread.java:73) 03-01 11:02:53.717: E/AndroidRuntime(26177): FATAL EXCEPTION: Thread-16428 03-01 11:02:53.717: E/AndroidRuntime(26177): java.lang.NullPointerException 03-01 11:02:53.717: E/AndroidRuntime(26177): at org.awesome.AndroidGame.MainGamePanel.render(MainGamePanel.java:192) 03-01 11:02:53.717: E/AndroidRuntime(26177): at org.awesome.AndroidGame.MainThread.run(MainThread.java:73) </code></pre> <p>Logcat when nullcheck is in place:</p> <pre><code>03-01 11:58:50.297: E/AndroidRuntime(32292): FATAL EXCEPTION: main 03-01 11:58:50.297: E/AndroidRuntime(32292): java.lang.IllegalThreadStateException: Thread already started. 03-01 11:58:50.297: E/AndroidRuntime(32292): at java.lang.Thread.start(Thread.java:1045) 03-01 11:58:50.297: E/AndroidRuntime(32292): at org.awesome.AndroidGame.MainGamePanel.surfaceCreated(MainGamePanel.java:83) 03-01 11:58:50.297: E/AndroidRuntime(32292): at android.view.SurfaceView.updateWindow(SurfaceView.java:569) 03-01 11:58:50.297: E/AndroidRuntime(32292): at android.view.SurfaceView.onWindowVisibilityChanged(SurfaceView.java:231) 03-01 11:58:50.297: E/AndroidRuntime(32292): at android.view.View.dispatchWindowVisibilityChanged(View.java:7537) 03-01 11:58:50.297: E/AndroidRuntime(32292): at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:1039) 03-01 11:58:50.297: E/AndroidRuntime(32292): at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:1039) 03-01 11:58:50.297: E/AndroidRuntime(32292): at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:1039) 03-01 11:58:50.297: E/AndroidRuntime(32292): at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1211) 03-01 11:58:50.297: E/AndroidRuntime(32292): at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:989) 03-01 11:58:50.297: E/AndroidRuntime(32292): at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:4351) 03-01 11:58:50.297: E/AndroidRuntime(32292): at android.view.Choreographer$CallbackRecord.run(Choreographer.java:749) 03-01 11:58:50.297: E/AndroidRuntime(32292): at android.view.Choreographer.doCallbacks(Choreographer.java:562) 03-01 11:58:50.297: E/AndroidRuntime(32292): at android.view.Choreographer.doFrame(Choreographer.java:532) 03-01 11:58:50.297: E/AndroidRuntime(32292): at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:735) 03-01 11:58:50.297: E/AndroidRuntime(32292): at android.os.Handler.handleCallback(Handler.java:725) 03-01 11:58:50.297: E/AndroidRuntime(32292): at android.os.Handler.dispatchMessage(Handler.java:92) 03-01 11:58:50.297: E/AndroidRuntime(32292): at android.os.Looper.loop(Looper.java:137) 03-01 11:58:50.297: E/AndroidRuntime(32292): at android.app.ActivityThread.main(ActivityThread.java:5039) 03-01 11:58:50.297: E/AndroidRuntime(32292): at java.lang.reflect.Method.invokeNative(Native Method) 03-01 11:58:50.297: E/AndroidRuntime(32292): at java.lang.reflect.Method.invoke(Method.java:511) 03-01 11:58:50.297: E/AndroidRuntime(32292): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) 03-01 11:58:50.297: E/AndroidRuntime(32292): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 03-01 11:58:50.297: E/AndroidRuntime(32292): at dalvik.system.NativeStart.main(Native Method) </code></pre>
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      1. POAndroid app not responding when closed
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    1. COWhen you say "close the app", do you mean hit the back button, hit the home button, or did provide custom exit functionality in your code?
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      1. POAndroid app not responding when closed
      1. USIgor Ganapolsky
    2. COBoth buttons crash my app, but I was talking specifically about the home button.
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    3. CODoes the stacktrace from LogCat point to a specific line of code?
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      1. USIgor Ganapolsky
 

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