CODEWITHSUNDEEP
androidcamera
Marco Seiz
Marco Seiz

Reputation: 954

Android: How to work with camera when activiy goes in background?

How can I release the camera, when my activity goes into background? (For example by pressing the standby button on the phone)

    public void onPause(){
    super.onPause();
    if (cam != null) {
        cam.stopPreview();
        cam.release();
        cam = null;
    }
}

@Override
protected void onResume(){
 super.onResume();
    rLayout = (RelativeLayout) findViewById (R.id.layout_background);
    cam = Camera.open();  
    cam.startPreview();
    p = cam.getParameters();
}

LogCat:

02-20 11:46:40.040: E/AndroidRuntime(26439): FATAL EXCEPTION: main
02-20 11:46:40.040: E/AndroidRuntime(26439): java.lang.RuntimeException: Unable to resume activity {spicysoftware.spicytaschenlampe/spicysoftware.spicytaschenlampe.FlashLight}: java.lang.RuntimeException: Fail to connect to camera service
02-20 11:46:40.040: E/AndroidRuntime(26439):    at android.app.ActivityThread.performResumeActivity(ActivityThread.java:2616)
02-20 11:46:40.040: E/AndroidRuntime(26439):    at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:2644)
02-20 11:46:40.040: E/AndroidRuntime(26439):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2130)
02-20 11:46:40.040: E/AndroidRuntime(26439):    at android.app.ActivityThread.access$600(ActivityThread.java:140)
02-20 11:46:40.040: E/AndroidRuntime(26439):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1227)
02-20 11:46:40.040: E/AndroidRuntime(26439):    at android.os.Handler.dispatchMessage(Handler.java:99)
02-20 11:46:40.040: E/AndroidRuntime(26439):    at android.os.Looper.loop(Looper.java:137)
02-20 11:46:40.040: E/AndroidRuntime(26439):    at android.app.ActivityThread.main(ActivityThread.java:4898)
02-20 11:46:40.040: E/AndroidRuntime(26439):    at java.lang.reflect.Method.invokeNative(Native Method)
02-20 11:46:40.040: E/AndroidRuntime(26439):    at java.lang.reflect.Method.invoke(Method.java:511)
02-20 11:46:40.040: E/AndroidRuntime(26439):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1008)
02-20 11:46:40.040: E/AndroidRuntime(26439):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:775)
02-20 11:46:40.040: E/AndroidRuntime(26439):    at dalvik.system.NativeStart.main(Native Method)
02-20 11:46:40.040: E/AndroidRuntime(26439): Caused by: java.lang.RuntimeException: Fail to connect to camera service
02-20 11:46:40.040: E/AndroidRuntime(26439):    at android.hardware.Camera.native_setup(Native Method)
02-20 11:46:40.040: E/AndroidRuntime(26439):    at android.hardware.Camera.<init>(Camera.java:353)
02-20 11:46:40.040: E/AndroidRuntime(26439):    at android.hardware.Camera.open(Camera.java:330)
02-20 11:46:40.040: E/AndroidRuntime(26439):    at spicysoftware.spicytaschenlampe.FlashLight.onResume(FlashLight.java:182)
02-20 11:46:40.040: E/AndroidRuntime(26439):    at android.app.Instrumentation.callActivityOnResume(Instrumentation.java:1199)
02-20 11:46:40.040: E/AndroidRuntime(26439):    at android.app.Activity.performResume(Activity.java:5280)
02-20 11:46:40.040: E/AndroidRuntime(26439):    at android.app.ActivityThread.performResumeActivity(ActivityThread.java:2606)
02-20 11:46:40.040: E/AndroidRuntime(26439):    ... 12 more

THIS IS HOW ITS WORKING:

    public void onPause(){
    super.onPause();
    Log.v("OnPause", "True");
    if (cam != null) {
        Log.v("OnPause", "Cam isn't null");
        cam.stopPreview();
        Log.v("OnPause", "CamPreview stopped");
        cam.release();
        Log.v("OnPause", "CamReleased");
        cam = null;
        Log.v("OnPause", "Cam is null");
    }
}


@Override
protected void onResume(){
 super.onResume();
 Log.v("OnResume", "True");
    if(cam != null){
        Log.v("OnResume", "Camera is in use");
    } else {
        Log.v("OnResume", "Camera isn't in use");
        rLayout = (RelativeLayout) findViewById (R.id.layout_background);
        cam = Camera.open();  
        Log.v("OnResume", "Camera has been opened");
        cam.startPreview();
        Log.v("OnResume", "CamPreview started");
        p = cam.getParameters();
        Log.v("OnResume", "Wrote parameters to variable p");
    }
}

Opening the camera in onResume does crash the app.

Best regards MSeiz5

Upvotes: 1

Views: 2965

Answers (2)

StarPinkER
StarPinkER

Reputation: 14271

Reopen and reset your camera in onResume. 

@Override
protected void onResume(){
 super.onResume();
 camera = Camera.open();

 // We resumed so lock the camera
 Camera.Parameters params = camera.getParameters();

 params.setFlashMode(Parameters.FLASH_MODE_ON);
 //params.setFocusMode(Parameters.FOCUS_MODE_AUTO);
 //params.setWhiteBalance(Parameters.WHITE_BALANCE_AUTO);
 params.setJpegQuality(100);

 camera.setParameters(params);
 ImageView overlay = (ImageView) findViewById(R.id.ImageView01);
 overlay.bringToFront();
}

Upvotes: 1

Aashish Bhatnagar
Aashish Bhatnagar

Reputation: 2605

you are releasing it just fine but on resume it must be throwing the null pointer as camera object is null please reinitialize it before using it it will be just like you do onCreate.

Upvotes: 0

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