After making a call programatically, my android app crashes

The title explains all... I have this snippet of code in my application:

String url = createTelUrl("3112007315");
Intent intent = new Intent(Intent.ACTION_CALL);
intent.setData(Uri.parse(url));
context.startActivity(intent);

It does make a call, but once the call ends, my application crashes. I'd like to return to my application once the call has finished, but I read this post and it seems not to be possible. So... is there anyway to at least pause my application and resume it once the call has finished?

EDIT:

Thanks for the two answers I received, I feel I'm really close to my goal... I had already done some of the things you guys suggested. But, maybe I didn't explain some details of the application... I'm developing Who Wants To Be A Millonarie game, so I need to implement calls (I don't know how it's called in USA or other countrys, but here we call it "call to a friend").

Anyway... I've done too many changes to this app and now it's not crashing. But, the Canvas where I draw the UI is not been showed once the called has ended.

I have a SurfaceView that holds the UI. For that SurfaceView I created a thread that is meant to refresh the UI... this is basically what the thread does:

@Override
public void run() {
    Canvas c;
    while (_run) {
        c = null;
        try {
            c = _surfaceHolder.lockCanvas(null);
            // Check if should wait
            synchronized (_surfaceHolder) {
                _panel.onDraw(c);
            }
        } finally {
            // do this in a finally so that if an exception is thrown
            // during th开发者_JAVA技巧e above, we don't leave the Surface in an
            // inconsistent state
            if (c != null) {
                _surfaceHolder.unlockCanvasAndPost(c);
            }
        }
    }
}

But, once the call has ended I get a black screen. The surface is there (I know it because it still can receive some touch events), but it's not showing anything. Another thing to take in account is how I'm starting the Thread from the SurfaceView class:

public void surfaceCreated(SurfaceHolder holder) {
    hilo.setRunning(true);
    try{
        hilo.start();
    }catch(IllegalThreadStateException ite){
        Log.e("wwtbam", "god dammed");
    }
}

This worked nice before I start implementing phone-calls. The problem here is that once the call has ended and it executes again the start method which throws a IllegalThreadStateException because the thread has already been started. I've tried using some 'technics' to pause the UI thread while calling but I haven't been able to solve this problem. I tried doing something like:

// this in the UI thread class
if(haveToWait)
    wait();
....
// this in the surface view class
if(callEnded)
    hilo.notify();

But that didn't work. I also have tried some other 'tricks' like using sleep(50); instead of wait(); but it does not work either.

With all that information I provided... what could you suggest to me?

The problem here is the place you're using to start the thread. Once you start a new call, your main activity will be paused and the surfaceview will be destroyed. Though, the thread will keep running. So, once your app takes the control back, the surface is created again and the start method will be invoked. That causes a IllegalThreadStateException.

The way to go here is to manipulate the thread out of the SurfaceView class. That will give you the control of the thread from the main activity, and you will be able to decide when to start or pause your thread.

Take a look of this example: http://code.google.com/p/apps-for-android/source/browse/trunk/SpriteMethodTest/src/com/android/spritemethodtest/

This is possible using an android.telephony.PhoneStateListener.

First, we need to take care of the manifest of the app:

We need the permission to make calls (duh!) as well as the permission to watch the phone state. The latter is needed so the app can react to the ending of a call as well. So we add these lines to out application manifest:

<uses-permission android:name="android.permission.CALL_PHONE" />
<uses-permission android:name="android.permission.READ_PHONE_STATE" />

Also, we don't want Android to start a different instance of our activity when the call has ended, so we set the launchMode attribute of the activity to "singleInstance".

<activity android:name=".CallTest" android:label="Calling Test" 
        android:launchMode="singleInstance" />

Having prepared everything in the manifest, we can now look at the activity making the call:

public class CallTest extends Activity {
    PhoneStateListener mListener;
    TelephonyManager mTelMgr;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        mListener = new CallEndedListener();
        mTelMgr = (TelephonyManager) this.getSystemService(TELEPHONY_SERVICE);
    }

    public void makecall(View v) {
        // Register our listener to be notified of the beginning
        // and ending of calls
        mTelMgr.listen(mListener, PhoneStateListener.LISTEN_CALL_STATE);

        // Start the call
        Intent call = new Intent(Intent.ACTION_CALL);
        call.setData(Uri.parse("tel:12345"));
        startActivity(call);
    }

    class CallEndedListener extends PhoneStateListener {
        boolean called = false;

        @Override
        public void onCallStateChanged(int state, String incomingNumber) {
            super.onCallStateChanged(state, incomingNumber);

            // Don't fire before the call was made
            if (state == TelephonyManager.CALL_STATE_OFFHOOK)
                called = true;

            // Call has ended -- now bring the activity back to front
            if (called && state == TelephonyManager.CALL_STATE_IDLE) {
                called = false;
                mTelMgr.listen(this, PhoneStateListener.LISTEN_NONE);
                startActivity(new Intent(CallTest.this, CallTest.class));
            }
        }
    }
}

The only new thing in the makecall method, compared to the code snippet in the question, is the PhoneStateListener implementation added right before actually making the call. This listener then gets notified by Android when an outgoing call is dialed, an incoming call is ringing or when an active call is ended.

Our implementation waits for the latter CALL_STATE_IDLE event and starts our activity again, so that after the call has ended we're back in our app where we left it. It then deregisters itself, so our activity doesn't get restarted every time the user ends a call not initiated by our own activity.

However, when registering for the CALL_STATE-events with the TelephonyManager, Android instantly fires a notification with the current status -- so our listener would get triggered before the call had even started. Therefore our listener implementation first waits until an outgoing call was started (CALL_STATE_OFFHOOK) and only after that happened reacts to the CALL_STATE_IDLE notification.

HTH!

As for the crash - please post the log and put your debugger onStart/onResume to find out why you're crashing. It's possible that something is initialized in the wrong place and you might something as simple as nullpointer.

As for the call end thing - i've never try this, but i'd try to register receiver, catch http://developer.android.com/reference/android/telephony/TelephonyManager.html#ACTION_PHONE_STATE_CHANGED Evaluate the state of the phone and do what you need to do .

Also there is more info here http://developer.android.com/reference/android/telephony/ http://developer.android.com/reference/android/telephony/PhoneStateListener.html

And finally you'll find examples of how to use that in the applications that are use that functionality in source.android.com