Android crashes when closing the application and reopening it

Question

I have a really simple Android app that just displays a blank white screen. When I close the application by pressing the HOME button, try opening the application again, it will work, and I will get the "Force Close" button. In Eclipse, I get this error: "ActivityManager: Warning: activity is not running because the current activity is saved for the user." How to fix this error?

public class HelloAndroid extends Activity { @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); requestWindowFeature(Window.FEATURE_NO_TITLE); getWindow().setFlags( WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN); setContentView(new Panel(this)); } class Panel extends SurfaceView implements SurfaceHolder.Callback { private TutorialThread _thread; public Panel(Context context) { super(context); // register our interest in hearing about changes to our surface SurfaceHolder holder = getHolder(); holder.addCallback(this); _thread = new TutorialThread(holder, this); setFocusable(true); } @Override public void onDraw(Canvas canvas) { // Clear the background canvas.drawColor(Color.WHITE); } @Override public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) { // resize canvas here } @Override public void surfaceCreated(SurfaceHolder holder) { _thread.setRunning(true); _thread.start(); } @Override public void surfaceDestroyed(SurfaceHolder holder) { // simply copied from sample application LunarLander: // we have to tell thread to shut down & wait for it to finish, or else // it might touch the Surface after we return and explode boolean retry = true; _thread.setRunning(false); while (retry) { try { _thread.join(); retry = false; } catch (InterruptedException e) { // we will try it again and again... } } } } class TutorialThread extends Thread { private SurfaceHolder _surfaceHolder; private Panel _panel; private boolean _run = false; public TutorialThread(SurfaceHolder surfaceHolder, Panel panel) { _surfaceHolder = surfaceHolder; _panel = panel; } public void setRunning(boolean run) { _run = run; } @Override public void run() { Canvas c; while (_run) { c = null; try { c = _surfaceHolder.lockCanvas(null); synchronized (_surfaceHolder) { _panel.onDraw(c); } } finally { // do this in a finally so that if an exception is thrown // during the above, we don't leave the Surface in an // inconsistent state if (c != null) { _surfaceHolder.unlockCanvasAndPost(c); } } } } } 

}

Adding LogCat

 03-15 15:36:05.579: INFO/AndroidRuntime(4441): NOTE: attach of thread 'Binder Thread #2' failed 03-15 15:36:05.719: DEBUG/AndroidRuntime(4449): >>>>>>>>>>>>>> AndroidRuntime START <<<<<<<<<<<<<< 03-15 15:36:05.719: DEBUG/AndroidRuntime(4449): CheckJNI is OFF 03-15 15:36:05.719: DEBUG/dalvikvm(4449): creating instr width table 03-15 15:36:05.759: DEBUG/AndroidRuntime(4449): --- registering native functions --- 03-15 15:36:05.969: INFO/ActivityManager(1294): Starting activity: Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10000000 cmp=com.example.helloandroid/.HelloAndroid } 03-15 15:36:05.979: DEBUG/Launcher(1371): onPause+ 03-15 15:36:05.979: DEBUG/Launcher.DragController(1371): +endDrag: false 03-15 15:36:05.979: DEBUG/Launcher.DragController(1371): mDragging == false 03-15 15:36:05.979: DEBUG/Launcher.DragController(1371): -endDrag: false 03-15 15:36:05.979: DEBUG/Launcher(1371): onPause- 03-15 15:36:05.999: DEBUG/AndroidRuntime(4428): Shutting down VM 03-15 15:36:05.999: DEBUG/AndroidRuntime(4449): Shutting down VM 03-15 15:36:05.999: WARN/dalvikvm(4428): threadid=1: thread exiting with uncaught exception (group=0x4001d7e0) 03-15 15:36:06.009: DEBUG/dalvikvm(4449): Debugger has detached; object registry had 1 entries 03-15 15:36:06.009: INFO/AndroidRuntime(4449): NOTE: attach of thread 'Binder Thread #3' failed 03-15 15:36:06.029: ERROR/AndroidRuntime(4428): FATAL EXCEPTION: main 03-15 15:36:06.029: ERROR/AndroidRuntime(4428): java.lang.IllegalThreadStateException: Thread already started. 03-15 15:36:06.029: ERROR/AndroidRuntime(4428): at java.lang.Thread.start(Thread.java:1322) 03-15 15:36:06.029: ERROR/AndroidRuntime(4428): at com.example.helloandroid.HelloAndroid$Panel.surfaceCreated(HelloAndroid.java:55) 03-15 15:36:06.029: ERROR/AndroidRuntime(4428): at android.view.SurfaceView.updateWindow(SurfaceView.java:538) 03-15 15:36:06.029: ERROR/AndroidRuntime(4428): at android.view.SurfaceView.onWindowVisibilityChanged(SurfaceView.java:206) 03-15 15:36:06.029: ERROR/AndroidRuntime(4428): at android.view.View.dispatchWindowVisibilityChanged(View.java:3888) 03-15 15:36:06.029: ERROR/AndroidRuntime(4428): at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:725) 03-15 15:36:06.029: ERROR/AndroidRuntime(4428): at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:725) 03-15 15:36:06.029: ERROR/AndroidRuntime(4428): at android.view.ViewRoot.performTraversals(ViewRoot.java:748) 03-15 15:36:06.029: ERROR/AndroidRuntime(4428): at android.view.ViewRoot.handleMessage(ViewRoot.java:1737) 03-15 15:36:06.029: ERROR/AndroidRuntime(4428): at android.os.Handler.dispatchMessage(Handler.java:99) 03-15 15:36:06.029: ERROR/AndroidRuntime(4428): at android.os.Looper.loop(Looper.java:123) 03-15 15:36:06.029: ERROR/AndroidRuntime(4428): at android.app.ActivityThread.main(ActivityThread.java:4627) 03-15 15:36:06.029: ERROR/AndroidRuntime(4428): at java.lang.reflect.Method.invokeNative(Native Method) 03-15 15:36:06.029: ERROR/AndroidRuntime(4428): at java.lang.reflect.Method.invoke(Method.java:521) 03-15 15:36:06.029: ERROR/AndroidRuntime(4428): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868) 03-15 15:36:06.029: ERROR/AndroidRuntime(4428): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626) 03-15 15:36:06.029: ERROR/AndroidRuntime(4428): at dalvik.system.NativeStart.main(Native Method) 03-15 15:36:06.039: WARN/ActivityManager(1294): Force finishing activity com.example.helloandroid/.HelloAndroid 03-15 15:36:06.541: WARN/ActivityManager(1294): Activity pause timeout for HistoryRecord{450300c0 com.example.helloandroid/.HelloAndroid} 03-15 15:36:06.549: DEBUG/Launcher(1371): onResume+ 03-15 15:36:06.549: DEBUG/Launcher.DragController(1371): +endDrag: false 03-15 15:36:06.549: DEBUG/Launcher.DragController(1371): mDragging == false 03-15 15:36:06.549: DEBUG/Launcher.DragController(1371): -endDrag: false 03-15 15:36:06.549: DEBUG/Launcher(1371): onResume- 03-15 15:36:08.645: ERROR/KINETO(1370): KLOG0C3- xmk_QueryOSQueue SDL Queue empty : WAIT_FOREVER 

Answer 1

I answered such a question here .

The error you get is probably caused by your Thread (without seeing the full Logcat, it's hard to say). You run it every time a surface is created, which will cause the application to crash, because you cannot call Thread.start() twice. Take a look at my link above for a more detailed description of the problem and its solution.

Since my explanation was not enough, I will post the whole solution:

Inside Runnable/Thread :

 private Object mPauseLock = new Object(); private boolean mPaused; // Constructor stuff. // This should be after your drawing/update code inside your thread run() code. synchronized (mPauseLock) { while (mPaused) { try { mPauseLock.wait(); } catch (InterruptedException e) { } } } // Two methods for your Runnable/Thread class to manage the thread properly. public void onPause() { synchronized (mPauseLock) { mPaused = true; } } public void onResume() { synchronized (mPauseLock) { mPaused = false; mPauseLock.notifyAll(); } } 

In your SurfaceView class:

 private boolean mGameIsRunning; @Override public void surfaceCreated(SurfaceHolder holder) { // Your own start method. start(); } public void start() { if (!mGameIsRunning) { thread.start(); mGameIsRunning = true; } else { thread.onResume(); } } 

Answer 2

The solution below has been verified. The code checks the status of the stream, and if termination creates a new one. There are no crashes, the only problem I see is the state of the game is not saved, so basically returning from pressing the HOME key starts the game again. postscript remember to pass the context from the Lunarview view and set mContextLunarView. Hope this helps. These forums are awesome. Keep it up.

 public void surfaceCreated(SurfaceHolder holder) { // start the thread here so that we don't busy-wait in run() // waiting for the surface to be created if(thread.getState() == Thread.State.TERMINATED) { //LunarView Thread state TERMINATED..make new...under CheckCreateThread thread = new LunarThread(holder, mContextLunarView, new Handler() { @Override public void handleMessage(Message m) { mStatusText.setVisibility(m.getData().getInt("viz")); mStatusText.setText(m.getData().getString("text")); } }); } thread.setRunning(true); thread.start(); } 

Answer 3

Here is a simple solution that may be acceptable in some cases, for example, a background animation screen and actions whose states do not need to be restored - surface activity should end on pause.

 protected void onPause() { super.onPause(); finish(); } 

The best solution is to transfer the creation of a stream from the constructor to onto the Creaed surface as follows:

 @Override public void surfaceCreated(SurfaceHolder holder) { _thread = new TutorialThread(holder, this); _thread.setRunning(true); _thread.start(); } 

Then create a pause flag in the stream loop:

 if(!pause){ _panel.onDraw(c); } 

Finally, in onPause and onRestore, a pause flag is set for activity:

  protected void onResume() { super.onResume(); pause = false; } protected void onPause() { super.onPause(); pause = true; } 

When the user clicks the "Main button" button, the "Finish" method is launched, which will disable the current "_thread" thread. When it returns to the application, surfaceCreated will assign the "_thread" link to the new thread, and the old thread object will be deleted by the garbage collector.