Android Camera - Sometimes When I Take Photos, The App Freezes And The Camera Is Non-usable

I have built an application which takes photos when you touch the preview. I can take many photos, but sometimes when i touch the preview to take a photo, there is no shutter sound

Solution 1:

I just run into this issue when testing my application on a Samsung Galaxy SII. You just have to remove the preview callback before taking the picture:

mCamera.setPreviewCallback(null);
mCamera.takePicture(null, null, mPictureCallback);

Solution 2:

I don't know what causes that bug, it would really help if you posted the loggcat output from the time from when this error happened.

But, I can make some gusesses. It looks like camera is locked (built-in camera does not work). If your app force closed, the camera lock might be caused by erroneus error handling in Samsung camera HAL. Especially in older phones, like Galaxy S, they did not do the best job at handling wrong, or not standard API calls.

Here are some suggestions of what may have caused this behaviour:

1. You should add a guard for picture taking. Right now, if you touch the screen and take picture, you can touch the screen again, before the picture finishes taking. So, camera.takePicture() will be called twice. The second one will fail. This is my best guess.

   Add some boolean isTakingPicture = false variable and then:

   publicbooleanonTouch(View v, MotionEvent event) {
     if (!isTakingPicture) {
       camera.takePicture(shutterCallback, rawCallback, jpegCallback);
       isTakingPicture = true;
     }
     returnfalse;
   }
   ...
   publicvoidonPictureTaken(byte[] data, Camera camera) {
     isTakingPicture = false;
     ...
   

2. What do you use previewCallback for? I doesn't do anything useful here. Preview callbacks sometimes can sometimes cause some pain, although your code looks fine to me. You can alwys try to remove it and check if that helps.

Solution 3:

I experienced a similar issue reported here. On LG p705 and Samsung Galaxy Trend, after taking a photo, the preview is frozen and camera was no longer usable until the phone was restarted. On Galaxy S3 however, the preview continues to display properly even after multiple photo snaps.

While debugging, I noticed that the relevant listener class was receiving more than one call when the camera button was pressed to take picture. I am unsure why it is being invoked twice, even though the button was only click once. In any case, thanks to Tomasz's suggestion to use of a boolean variable, the second call skips taking photo while the first attempt is in progress. And thanks Eyal for the question too. :)