My app is using camera. i'm having a CameraActivity class and CameraFragment class,
CameraFragment is responsible for releasing the camera:
#Override
public void onPause() {
super.onPause();
if (mCamera != null) {
mCamera.release();
mCamera = null;
}
}
My app crashed while taking a picture. for some reason the camera was not released. now i can't get the camera object nowhere! Also the android Camera app is not working with an error "Can't connect to the camera"
now i know that the camera is a singleton object and only one app can get it in a time.
what i don't understand is why onPause didn't run and how can i protect the camera instance better?
Also if something like that happens, how can i force release the camera object? it it a good idea?
sadly i don't have the information why the app crashed at the first place.
Thanks for your help.
Roy
This should help:
private static void unCaughtExceptionHandler() {
Thread.setDefaultUncaughtExceptionHandler(new Thread.UncaughtExceptionHandler() {
public void uncaughtException(final Thread thread, final Throwable ex) {
ex.printStackTrace();
releaseCamera();
System.exit(0);
}
});
}
Related
I am using the camera flash for a Morse code application. I create a new camera object when the class is created. The user has a button which is used to reset and also release the camera when required (If they want to stop the light Morse sequence prematurely).
The problem is that when they hit the reset button because the activity is not created or loaded again the camera never get reinitialized - this is a problem because the method of the class that it is calling is used by another class and releases the camera when it is has completed it's function. I am not sure how to structure the code in a way that allows me to do this.
I am wondering if anyone has any advice/suggestions in how to achieve this?
//Camera object being declared
Light light;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity__morse);
//Camera object being initialized
light = new Light
}
//Reset user pressed a button
public void reset(View view)
{
light.release();
}
//Releasing the camera
public void release() {
if(camera != null)
{
camera.stopPreview();
camera.release();
camera = null;
}
}
Don't initialize the camera in onCreate. Do it in onStart, and release it in onStop.
I have a live wallpaper that just draws triangles, very simple, and runs smoothly all time. After testing found that when I open the camera to take pictures the phone freezes for about 10 seconds, then the camera opens and the wallpaper crashes and the message "Unfortunately, Live Wallpaper has stopped." appears. Also found that when I open any barcode scanner app the problem raises again because the scanner uses the camera too. Seems the problem raises when the camera app runs. Any ideas what's causing it?
hi #Bullet Camera is just open ones, if it open through any other apps then, you can can not access your camera, Solution is that, where you use camera please release that after no used.
main problem is that, in your app (app in that you are using camera) , so , you release camera after used.
like following :
#Override
public void onPause() {
// TODO Auto-generated method stub
super.onPause();
if (camera != null) {
camera.stopPreview();
camera.release();
camera = null;
}
}
when you need
private void releaseCameraAndPreview() {
if (camera != null) {
camera.release();
camera = null;
}
}
or
public void stopCamera() {
if (cameraDevice != null) {
cameraDevice.stopPreview();
cameraDevice.setPreviewCallback(null);
cameraDevice.release();
cameraDevice = null;
System.out.println("in to the stop video");
}
}
I am making an android flashlight app. I it has two activities, a main activity and a settings activity where the camera led can be toggled on and off. It also has another class where all the camera changes are handled like opening it, releasing it, and turning the light on and off.
I kept getting errors when turning on the led based on shared preference settings because I was not opening and releasing the camera in the correct activity lifecycle stages. I fixed the issues by releasing the camera when onPause is called in either activity and turning the led on or off (based on shared preference settings) when onResume is called in either activity.
The problem I am having now is that if the led is on, it turns off briefly when switching from one activity to the other because I have to release the camera and then open again in the new activity. Can anyone help me figure out a way to eliminate this problem? Where should I open and release the camera? I have tried releasing it in on destroy but the led stays on when the app is minimized to the background, which is undesirable. Thanks for any suggestions.
In both main and settings activity I have:
#Override
protected void onResume() {
super.onResume();
if (sp.getBoolean("LED_TOGGLE_CB", false) == true) {
flash.turnFlashOn();
}
}
#Override
protected void onPause() {
super.onPause();
flash.killCamera();
}
In the Flash class I have:
void getCamera() {
if(camera == null) {
try {
camera = Camera.open();
params = camera.getParameters();
} catch(RuntimeException e) {
Log.e("Camera Error. Failed to Open. Error: ", e.getMessage());
}
}
}
void turnFlashOn() {
getCamera();
params.setFlashMode(Parameters.FLASH_MODE_TORCH);
camera.setParameters(params);
camera.startPreview();
isFlashOn = true;
}
public void killCamera() {
if (camera != null) {
camera.stopPreview();
camera.setPreviewCallback(null);
camera.release();
camera = null;
}
}
I'm trying to create a Glass GDK app that uses the Camera service to show a preview. Unfortunately, I currently have a bug where a RuntimeException is thrown when trying to open a Camera using Camera.open(). I only encounter this bug when opening the activity through a voice trigger, not by selecting the app from the "launcher" menu.
Is there a difference in how an Activity is launched through this menu versus the voice trigger?
Some of the relevant code is below.
#Override
public void onCreate(Bundle savedInstanceState) {
mGestureDetector = createGestureDetector(this);
super.onCreate(savedInstanceState);
ctx = this;
act = this;
setContentView(R.layout.activity_main);
preview = new Preview(this, (SurfaceView)findViewById(R.id.surfaceView));
((FrameLayout) findViewById(R.id.preview)).addView(preview);
preview.setKeepScreenOn(true);
}
#Override
protected void onResume() {
super.onResume();
try {
if (camera == null) {
Log.d(TAG, "Opening a camera on resume.");
camera = Camera.open();
preview.setCamera(camera);
camera.startPreview();
}
} catch(java.lang.RuntimeException e) {
Log.e(TAG, e.getMessage());
}
}
#Override
protected void onPause() {
if(camera != null) {
camera.stopPreview();
preview.setCamera(null);
Log.d(TAG, "Releasing a camera on pause.");
camera.release();
camera = null;
}
super.onPause();
}
#Override
protected void onDestroy() {
if(camera != null) {
camera.stopPreview();
preview.setCamera(null);
Log.d(TAG, "Releasing a camera on destory.");
camera.release();
camera = null;
}
super.onDestroy();
}
Since it doesn't work when using the voice trigger, it sounds like a possible race condition where the microphone isn't released by the time your activity is displayed on the screen.
Can you try an approach that uses exponential back-off to capture the camera? Basically try to capture the camera and if you get an exception, try again after a short amount of time, increasing the wait time slightly for a fixed number of attempts.
Please also consider filing a bug on the issue tracker, especially if you can reliably find out how much of a delay is needed before the camera/mic can be acquired.
The problem is caused by the delay between the voice recogniser closing event and the camera open event, which is causing a memory overload.
To avoid the problem when launching the app which will be triggered with voice,
pause the app for certain time (1000 Milli seconds will do) from opening the camera soon.
In the below code I am delaying my QR scanner to open from opening for 1000 Milli seconds. This works fine for me. If you want a you can increase the time interval.
Handler handler = new Handler() {
#Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
intent = new Intent("com.google.zxing.client.android.SCAN");
startActivityForResult(intent, 0);
}
};
// sleeper time
handler.sendEmptyMessageDelayed(0, 1000);
I'm using the Android APIDemo sample code.
When I run the CameraPreview example, at first it was giving me an error.
I traced that one down and the sample was working for a while.
Now, it no longer works. It says
ERROR/AndroidRuntime(2949): java.lang.RuntimeException: Fail to connect to camera service
What can be causing that? It happens when camera.open() is called.
Thanks,
Tee
Be sure to properly release all the aquired camera resources:
#Override
public void surfaceDestroyed(SurfaceHolder holder) {
if (mCam != null) {
mCam.stopPreview();
mCam.setPreviewCallback(null);
mCam.release();
mCam = null;
}
}
#Override
public void surfaceCreated(SurfaceHolder holder) {
if (mCam == null) {
mCam = Camera.open();
try {
mCam.setPreviewDisplay(holder);
// TODO test how much setPreviewCallbackWithBuffer is faster
mCam.setPreviewCallback(this);
} catch (IOException e) {
mCam.release();
mCam = null;
}
}
}
Make sure your <uses-permission> elements are in the proper positions in your AndroidManifest.xml file.
It happens if your activity does not close the camera properly in surfaceDestroyed or onConfigurationChanged etc...
Don't forget to do this everytime you go out of your activity:
if (camera!=null){
camera.stopPreview();
camera.release();
camera=null;
}
Another reason of this error is when you try to open camera but some other application or even your application is already using camera.
I also get this type of issue on a HTC device. To solve add this code:
#Override
protected void onDestroy() {
// TODO Auto-generated method stub
super.onDestroy();
if (camera!=null)
{
camera.stopPreview();
camera.release();
camera=null;
}
}
And yet you cannot start camera then restart device.
Also, if you are using the emulator, make sure you have selected to Emulate the Front Camera and/or the Back Camera.
Android Virtual Device Manager->Select Device->Edit->Front Camera->Emulated
As others mention, you have to call release() on your camera object when you're finished.
I wasn't doing this initially, so I changed my code but it still gave me the same error. I was deploying directly to a physical handset and had to restart the phone before it worked
I also received this error when I was testing and stopped execution before reaching the point in code when the:
if (camera!=null){
camera.stopPreview();
camera.release();
camera=null;
}
was called. This then blocked the camera because it hadn't een released properly. My solution was to turn the camera off and back on again. You can confirm this is the case by trying to use the inbuilt Camera app in your phone. It won't work either because it is still busy.
Second #matt-burns however you might want to check that you're only trying to get the camera once. I had forgotten to comment out a line and was trying to launch two activities that would both try to obtain the camera.