法释（）异常无法恢复与Android摄像头之后调用 [英] method called after release() exception unable to resume with android camera
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问题描述
在开发相机应用，我遇到了一个例外，只有发生了，当我切换到其他应用程序（的onPause（）我的应用程序）。
While developing a camera app I've encountered an exception that only happened when I switch to other app (onPause() for my app).
01-15 17:22:15.017: E/AndroidRuntime(14336): FATAL EXCEPTION: main
01-15 17:22:15.017: E/AndroidRuntime(14336): java.lang.RuntimeException: Method called after release()
01-15 17:22:15.017: E/AndroidRuntime(14336): at android.hardware.Camera.setPreviewDisplay(Native Method)
01-15 17:22:15.017: E/AndroidRuntime(14336): at android.hardware.Camera.setPreviewDisplay(Camera.java:357)
01-15 17:22:15.017: E/AndroidRuntime(14336): at com.sora.cbir.yuki.image.leaf.CameraPreview.surfaceCreated(CameraPreview.java:32)
01-15 17:22:15.017: E/AndroidRuntime(14336): at android.view.SurfaceView.updateWindow(SurfaceView.java:551)
01-15 17:22:15.017: E/AndroidRuntime(14336): at android.view.SurfaceView.onWindowVisibilityChanged(SurfaceView.java:213)
01-15 17:22:15.017: E/AndroidRuntime(14336): at android.view.View.dispatchWindowVisibilityChanged(View.java:4075)
01-15 17:22:15.017: E/AndroidRuntime(14336): at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:742)
01-15 17:22:15.017: E/AndroidRuntime(14336): at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:742)
01-15 17:22:15.017: E/AndroidRuntime(14336): at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:742)
01-15 17:22:15.017: E/AndroidRuntime(14336): at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:742)
01-15 17:22:15.017: E/AndroidRuntime(14336): at android.view.ViewRoot.performTraversals(ViewRoot.java:858)
01-15 17:22:15.017: E/AndroidRuntime(14336): at android.view.ViewRoot.handleMessage(ViewRoot.java:1995)
01-15 17:22:15.017: E/AndroidRuntime(14336): at android.os.Handler.dispatchMessage(Handler.java:99)
01-15 17:22:15.017: E/AndroidRuntime(14336): at android.os.Looper.loop(Looper.java:150)
01-15 17:22:15.017: E/AndroidRuntime(14336): at android.app.ActivityThread.main(ActivityThread.java:4389)
01-15 17:22:15.017: E/AndroidRuntime(14336): at java.lang.reflect.Method.invokeNative(Native Method)
01-15 17:22:15.017: E/AndroidRuntime(14336): at java.lang.reflect.Method.invoke(Method.java:507)
01-15 17:22:15.017: E/AndroidRuntime(14336): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:849)
01-15 17:22:15.017: E/AndroidRuntime(14336): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:607)
01-15 17:22:15.017: E/AndroidRuntime(14336): at dalvik.system.NativeStart.main(Native Method)
我做了一些研究，发现我需要添加
I did some research and found out that I need to add
mCamera.setPreviewCallback(null);
作为一种变通方法为Android的摄像头堆栈
as a workaround for Android's camera stack
我的的onPause（）现在看起来是这样的：
my onPause() now looks like this:
@Override
protected void onPause() {
super.onPause();
try
{
// release the camera immediately on pause event
//releaseCamera();
mCamera.stopPreview();
mCamera.setPreviewCallback(null);
mCamera.release();
mCamera = null;
}
catch(Exception e)
{
e.printStackTrace();
}
}
和我的 onResume（）：
@Override
protected void onResume()
{
super.onResume();
try
{
mCamera.setPreviewCallback(null);
mCamera = getCameraInstance();
//mCamera.setPreviewCallback(null);
mPreview = new CameraPreview(Imageupload.this, mCamera);//set preview
preview.addView(mPreview);
} catch (Exception e){
Log.d(TAG, "Error starting camera preview: " + e.getMessage());
}
}
}
终于我的 getCameraInstance（）方法：
public Camera getCameraInstance(){
Camera camera = null;
try {
camera = Camera.open(); // attempt to get a Camera instance
}
catch (Exception e){
// Camera is not available (in use or does not exist)
}
Camera.Parameters parameters = camera.getParameters();
//mPreviewSize = getBestPreviewSize(parameters, wt, ht);
//mPictureSize = getBestPictureSize(parameters, wt, ht);
//Shift W & H => if camera rotates 90 deg
mPreviewSize = getOptimalPreviewSize(parameters, wt, ht); //original => wt,ht
mPictureSize = getOptimalPictureSize(parameters, wt, ht); //original => wt,ht
Log.d("CAMERA", "SCREEN RESOLUTION H: "+ht);
Log.d("CAMERA", "SCREEN RESOLUTION W: "+wt);
Log.d("CAMERA", "PREVIEW RESOLUTION H: "+mPreviewSize.height);
Log.d("CAMERA", "PREVIEW RESOLUTION W: "+mPreviewSize.width);
Log.d("CAMERA", "PICTURE RESOLUTION H: "+mPictureSize.height);
Log.d("CAMERA", "PICTURE RESOLUTION W: "+mPictureSize.width);
//set preview size based on device screen
parameters.setPreviewSize(mPreviewSize.width, mPreviewSize.height);
//set picture size based on device screen
parameters.setPictureSize(mPictureSize.width, mPictureSize.height);
//set output camera mode
parameters.setPictureFormat(PixelFormat.JPEG);
//set focous mode
parameters.setFocusMode(FOCUS_MODE_AUTO);
//set flash mode
parameters.setFlashMode("auto");
List<int[]> fps = parameters.getSupportedPreviewFpsRange();
//System.out.println("FPS size: " +fps.size());
//System.out.println("MAX FPS:"+(fps.get(fps.size()-1)[1])/1000);
//log min and max camera supported fps
Log.d("CAMERA", "CAMERA MAX FPS: "+(fps.get(fps.size()-1)[1])/1000);
Log.d("CAMERA", "CAMERA MIN FPS: "+(fps.get(fps.size()-1)[0])/1000);
if(camera_fps)
{
parameters.setPreviewFpsRange(fps.get(fps.size()-1)[1], fps.get(fps.size()-1)[1]);
}
//set camera parameters
camera.setParameters(parameters);
Toast.makeText(getApplicationContext(), "Your device are capable of previewing @" + fps.get(fps.size()-1)[1]/1000+"fps!",Toast.LENGTH_SHORT).show();
return camera; // returns null if camera is unavailable
}
在如何解决这一问题的任何想法？
any ideas on how to fix this?
推荐答案
我有同样的问题。 mCamera.set previewCallback（空）; 并没有帮助。在我的活动我已经添加这 releaseCamera ：
I've got the same problem. mCamera.setPreviewCallback(null); didn't help. In my activity I've added this to releaseCamera:
mPreview.getHolder().removeCallback(mPreview);
和它的作品了。
这篇关于法释（）异常无法恢复与Android摄像头之后调用的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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