I have some troubles with the onPause() onResume() camera live cycle: Camera with preview, and taking photos works totally fine. With one exceptions:
I start the app, click the home button, switch back to the app and take another shot.
Result: shuttercallback is still executed (see code), but jpeg callback isn't anymore! Then my galaxy S vibrates, and the screen stays black, since startPreview() is not re-triggered after jpegCallback. The stack trace is far from usefull for me. Strange thing is that this only happens on my Galaxy S, not on the emulator. I have really no clue how to move on :/ Anyone has an idea what could be usefull?
10-28 18:59:40.649: ERROR/SecCamera(4291): SetRotate(angle(0)) 10-28 18:59:40.649: ERROR/CameraHardwareSec(4291): ====setParameters processingmethod = (null) 10-28 18:59:40.649: ERROR/SecCamera(4291): setRecordingSize(width(800), height(480)) 10-28 18:59:40.673: ERROR/SecCamera(4291): SetRotate(angle(0)) 10-28 18:59:40.673: ERROR/CameraHardwareSec(4291): ====setParameters processingmethod = (null) 10-28 18:59:40.673: ERROR/SecCamera(4291): setRecordingSize(width(800), height(480)) 10-28 18:59:40.692: ERROR/SecCamera(4291): SetRotate(angle(0)) 10-28 18:59:40.692: ERROR/CameraHardwareSec(4291): ====setParameters processingmethod = (null) 10-28 18:59:40.692: ERROR/SecCamera(4291): setRecordingSize(width(800), height(480)) 10-28 18:59:40.712: ERROR/SecCamera(4291): SetRotate(angle(0)) 10-28 18:59:40.712: ERROR/CameraHardwareSec(4291): ====setParameters processingmethod = (null) 10-28 18:59:40.712: ERROR/SecCamera(4291): setRecordingSize(width(800), height(480)) 10-28 18:59:40.751: ERROR/CameraHardwareSec(4291): stopPreview() 10-28 18:59:40.751: ERROR/SecCamera(4291): cancelAutofocus() 10-28 18:59:40.751: ERROR/SecCamera(4291): cancelAutofocus() end, 0, 4 10-28 18:59:40.768: ERROR/SecCamera(4291): stopPreview() 10-28 18:59:40.768: ERROR/SecCamera(4291): fimc_v4l2_streamoff() 10-28 18:59:40.797: ERROR/CameraHardwareSec(4291): stopPreview() end 10-28 18:59:41.622: ERROR/SecCamera(4291): fimc_v4l2_streamoff() 10-28 18:59:46.536: ERROR/dalvikvm(2993): Failed to write stack traces to /data/anr/traces.txt (2775 of 2970): Unknown error: 0 10-28 18:59:46.540: ERROR/dalvikvm(2919): Failed to write stack traces to /data/anr/traces.txt (-1 of 3414): Math result not representable 10-28 18:59:46.610: ERROR/dalvikvm(3044): Failed to write stack traces to /data/anr/traces.txt (3354 of 7154): Math result not representable ...
Here is my (shortened) code:
public class CameraActivity extends Activity implements MenuViewCallback, CutoutPathManagerCallback {
public static final String TAG = "CutoutCamera";
Preview preview;
OverlayView overlay;
static MenuView menuView;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Hide the window title.
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);
...
preview = (Preview) this.findViewById(R.id.preview);
...
}
...
@Override
protected void onResume() {
super.onResume();
this.log("onResume()");
preview.openCamera();
}
@Override
protected void onPause() {
super.onPause();
this.log("onPause()");
if (preview.camera != null) {
preview.camera.release();
preview.camera = null;
}
}
// Called when shutter is opened
ShutterCallback shutterCallback = new ShutterCallback() { //
public void onShutter() {
Log.d(TAG, "onShutter'd");
}
};
// Handles data for raw picture
PictureCallback rawCallback = new PictureCallback() { //
public void onPictureTaken(byte[] data, Camera camera) {
Log.d(TAG, "onPictureTaken - raw");
}
};
// Handles data for jpeg picture
PictureCallback jpegCallback = new PictureCallback() { //
public void onPictureTaken(byte[] data, Camera camera) {
Log.d(TAG, "onPictureTaken - jpeg");
...
}
};
@Override
public void shootButtonClicked() {
preview.camera.takePicture(shutterCallback, rawCallback, jpegCallback);
}
@Override
public void focusButtonClicked() {
preview.camera.autoFocus(new Camera.AutoFocusCallback() {
public void onAutoFocus(boolean success, Camera camera) {
}
});
}
}
/**
* order of execution:
* openCamera()
* onMeasure()
* onLayout()
* onMeasure()
* onLayout()
* surfaceCreated()
* surfaceChanged()
* onMeasure()
* onLayout()
* onMeasure()
* @author stephan
*
*/
class Preview extends ViewGroup implements SurfaceHolder.Callback { //
private static final String TAG = "Preview";
SurfaceHolder mHolder; //
public Camera camera; //
private List supportedPreviewSizes;
private Size previewSize;
SurfaceView mSurfaceView;
CameraActivity cameraActivity;
int l2 = 0, t2 = 0, r2 = 0, b2 = 0;
int padding = 20;
Size optimalPreviewSize, optimalPictureSize;
// the size of this view. gets set in onMeasure()
int fullWidth, fullHeight;
public Preview(Context context) {
super(context);
init(context);
}
public Preview(Context context, AttributeSet attrs) {
super(context, attrs);
init(context);
}
public Preview(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
init(context);
}
private void init(Context context) {
setKeepScreenOn(true);
cameraActivity = (CameraActivity) context;
mSurfaceView = new SurfaceView(context);
addView(mSurfaceView);
mHolder = mSurfaceView.getHolder(); //
mHolder.addCallback(this); //
mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS); //
}
...
public void openCamera() {
cameraActivity.log("openCamera()");
if (this.camera == null) {
cameraActivity.log("Camera.open()");
this.camera = Camera.open();
//supportedPreviewSizes = camera.getParameters().getSupportedPreviewSizes();
requestLayout(); // -> onMeassure() -> onLayout()
}
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
cameraActivity.log("onMeasure()");
// We purposely disregard child measurements because act as a
// wrapper to a SurfaceView that centers the camera preview instead
// of stretching it.
fullWidth = resolveSize(getSuggestedMinimumWidth(), widthMeasureSpec);
fullHeight = resolveSize(getSuggestedMinimumHeight(), heightMeasureSpec);
setMeasuredDimension(fullWidth, fullHeight);
if(this.camera != null){
cameraActivity.log("fullSize:"+fullWidth+"x"+fullHeight);
this.setCameraPreviewSize();
this.setCameraPictureSize();
}
}
private void calcScaledPreviewSize(){
...
}
...
private void setCameraPreviewSize() {
Camera.Parameters parameters = camera.getParameters();
if(parameters.getPreviewSize() != this.getOptimalPreviewSize()){
parameters.setPreviewSize(this.getOptimalPreviewSize().width, this.getOptimalPreviewSize().height);
this.camera.setParameters(parameters);
}
}
private void setCameraPictureSize() {
Camera.Parameters parameters = this.camera.getParameters();
if(parameters.getPictureSize() != this.getOptimalCameraPictureSize()){
parameters.setPictureSize(getOptimalCameraPictureSize().width, getOptimalCameraPictureSize().height);
this.camera.setParameters(parameters);
}
}
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
cameraActivity.log("onLayout()");
if (changed && getChildCount() > 0 && this.camera != null) {
final View child = getChildAt(0);
cameraActivity.log("r:"+this.getPreviewRight()+" l:"+this.getPreviewLeft()+" b:"+this.getPreviewBottom()+" t:"+this.getPreviewTop());
child.layout(this.getPreviewLeft(), this.getPreviewTop(), this.getPreviewRight(), this.getPreviewBottom());
cameraActivity.initOverlay(this.getPreviewLeft(),this.getPreviewTop(),this.getPreviewRight(),this.getPreviewBottom());
}
}
private Size getOptimalPreviewSize() {
if(optimalPreviewSize == null){
//calculate optimal preview size
}
return optimalPreviewSize;
}
private Size getOptimalCameraPictureSize() {
if(optimalPictureSize == null){
//calculate optimal image size
}
return optimalPictureSize;
}
// Called once the holder is ready
public void surfaceCreated(SurfaceHolder holder) { //
// The Surface has been created, acquire the camera and tell it where
// to draw.
cameraActivity.log("surfaceCreated()");
try {
if (this.camera != null) {
this.camera.setPreviewDisplay(holder);
}
} catch (IOException exception) {
Log.e(TAG, "IOException caused by setPreviewDisplay()", exception);
}
}
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
cameraActivity.log("surfaceChanged()");
if (camera != null) {
Camera.Parameters parameters = camera.getParameters();
parameters.setPreviewSize(getOptimalPreviewSize().width, getOptimalPreviewSize().height);
requestLayout();
camera.setParameters(parameters);
camera.startPreview();
}
}
public void surfaceDestroyed(SurfaceHolder holder) { //
cameraActivity.log("surfaceDestroyed()");
if(this.camera != null){
camera.stopPreview();
}
}
public void releaseCamera(){
cameraActivity.log("releaseCamera()");
if (camera != null) {
camera.stopPreview();
camera.setPreviewCallback(null);
camera.release();
camera = null;
}
}
}
stoefln
This is how I fixed it 100%, finally (working on every device I tried it on, including Galaxy S):
I destroyed the camere preview object onResume and reinstantiated all together (like on startup). More details here:
It's a bit late to reach this post but i had the similar problem. First of all, if you using customer rom, it could be the problem of camera driver (mine one X8 runniing 4.0.4). The problem also exists if you press power button to put the phone in standby mode and bring it back in a short time (with or without home screen lock). After try and error i found that put a short delay after shut down camera before super.onPause is the best. My code as below.
@Override
public void onPause() {
// Log.d(TAG,"ccp_onPause");
closeCamera();
try {
Thread.sleep(500);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
super.onPause();
}
and closeCamera();
public void closeCamera() {
if (mCamera != null) {
mCamera.stopPreview();
mCamera.setPreviewCallback(null);
mCamera.lock();
mCamera.release();
mCamera=null;
requestLayout();
}
}
My guess is that all you have to do, is to create a setter method in Preview for resetting camera (the local camera object in Preview becomes invalid after onPause() since camera is released, but rest of the state of Preview is still maintained).
来源：https://stackoverflow.com/questions/7935292/android-camera-onpause-onresume-issue