当我连续点击“捕获”按钮（没有任何中断）时，获取运行时异常如何解决此问题？
如果它不可能，那我怎么处理这个例外？
btnCapture = (ImageButton) findViewById(R.id.btnCapture);
final MediaPlayer mp = MediaPlayer.create(CameraLauncherActivity.this, R.raw.button);
btnCapture.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// line where getting RuntimeException
camera.takePicture(null, null, mPicture);
}
});
日志：
02-12 14:48:41.580: E/AndroidRuntime(6997): FATAL EXCEPTION: main
02-12 14:48:41.580: E/AndroidRuntime(6997): java.lang.RuntimeException: takePicture failed
02-12 14:48:41.580: E/AndroidRuntime(6997): at android.hardware.Camera.native_takePicture(Native Method)
02-12 14:48:41.580: E/AndroidRuntime(6997): at android.hardware.Camera.takePicture(Camera.java:1126)
02-12 14:48:41.580: E/AndroidRuntime(6997): at android.hardware.Camera.takePicture(Camera.java:1071)
02-12 14:48:41.580: E/AndroidRuntime(6997): at app.cam.shane.CameraLauncherActivity$3.onClick(CameraLauncherActivity.java:116)
02-12 14:48:41.580: E/AndroidRuntime(6997): at android.view.View.performClick(View.java:4223)
02-12 14:48:41.580: E/AndroidRuntime(6997): at android.view.View$PerformClick.run(View.java:17275)
02-12 14:48:41.580: E/AndroidRuntime(6997): at android.os.Handler.handleCallback(Handler.java:615)
02-12 14:48:41.580: E/AndroidRuntime(6997): at android.os.Handler.dispatchMessage(Handler.java:92)
02-12 14:48:41.580: E/AndroidRuntime(6997): at android.os.Looper.loop(Looper.java:137)
02-12 14:48:41.580: E/AndroidRuntime(6997): at android.app.ActivityThread.main(ActivityThread.java:4921)
02-12 14:48:41.580: E/AndroidRuntime(6997): at java.lang.reflect.Method.invokeNative(Native Method)
02-12 14:48:41.580: E/AndroidRuntime(6997): at java.lang.reflect.Method.invoke(Method.java:511)
02-12 14:48:41.580: E/AndroidRuntime(6997): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1036)
02-12 14:48:41.580: E/AndroidRuntime(6997): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:803)
02-12 14:48:41.580: E/AndroidRuntime(6997): at dalvik.system.NativeStart.main(Native Method)
注意： - 就像在布丁相机中一样，它们允许用户连续点击捕获按钮，但它们永远不会显示异常，如果你进行50次点击它将捕获10个或更多图像，每个图像在特定时间后但不显示异常，如我进入我的代码，以同样的方式我如何处理这个异常？
完整代码：
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_camera);
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
preview=(SurfaceView)findViewById(R.id.surface);
previewHolder=preview.getHolder();
previewHolder.addCallback(surfaceCallback);
previewHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
btnCapture = (ImageButton) findViewById(R.id.btnCapture);
final MediaPlayer mp = MediaPlayer.create(CameraLauncherActivity.this, R.raw.button);
btnCapture.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
mp.start();
camera.takePicture(null, null, mPicture);
}
});
@Override
public void onResume() {
super.onResume();
camera=Camera.open();
}
@Override
public void onPause() {
super.onPause();
if (inPreview) {
camera.stopPreview();
}
camera.release();
camera=null;
inPreview=false;
}
private Camera.Size getBestPreviewSize(int width, int height,
Camera.Parameters parameters) {
Camera.Size result=null;
for (Camera.Size size : parameters.getSupportedPreviewSizes()) {
if (size.width <= width && size.height <= height) {
if (result == null) {
result=size;
}
else {
int resultArea=result.width * result.height;
int newArea=size.width * size.height;
if (newArea > resultArea) {
result=size;
}
}
}
}
return(result);
}
private Camera.Size getSmallestPictureSize(Camera.Parameters parameters) {
Camera.Size result=null;
for (Camera.Size size : parameters.getSupportedPictureSizes()) {
if (result == null) {
result=size;
}
else {
int resultArea=result.width * result.height;
int newArea=size.width * size.height;
if (newArea < resultArea) {
result=size;
}
}
}
return(result);
}
SurfaceHolder.Callback surfaceCallback=new SurfaceHolder.Callback(){
public void surfaceCreated(SurfaceHolder holder) {
try {
camera.setPreviewDisplay(previewHolder);
} catch (Throwable t) {
Log.e("PreviewDemo-surfaceCallback",
"Exception in setPreviewDisplay()", t);
Toast.makeText(CameraLauncherActivity.this, t.getMessage(), Toast.LENGTH_LONG).show();
}
}
public void surfaceChanged(SurfaceHolder holder,int format, int width,int height) {
params = camera.getParameters();
params.setFlashMode(Camera.Parameters.FLASH_MODE_ON);
Camera.Size size = getBestPreviewSize(width, height, params);
Camera.Size pictureSize=getSmallestPictureSize(params);
if (size != null && pictureSize != null) {
params.setPreviewSize(size.width, size.height);
params.setPictureSize(pictureSize.width,
pictureSize.height);
camera.setParameters(params);
camera.startPreview();
inPreview=true;
}
}
public void surfaceDestroyed(SurfaceHolder holder) {
}
};
PictureCallback mPicture = new PictureCallback() {
@Override
public void onPictureTaken(byte[] data, Camera camera) {
pictureFile = getOutputMediaFile();
camera.startPreview();
if (pictureFile == null) {
return;
}
try {
FileOutputStream fos = new FileOutputStream(pictureFile);
fos.write(data);
fos.close();
} catch (FileNotFoundException e) {
} catch (IOException e) {
}
}
};
static File getOutputMediaFile() {
/* yyyy-MM-dd'T'HH:mm:ss.SSSZ */
timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss")
.format(new Date());
// file name
mediaFile = new File(LoginActivity.mediaStorageDir.getPath() + File.separator
+ "IMG_" + timeStamp + ".jpg");
return mediaFile;
}
}
首先，在onPictureTaken中捕获您的异常，留下空捕获部分不是一个好习惯。然后，我会添加一个标志，以防止在保存上一张图片时调用takePicture（）。稍后在你的按钮onClick上你会检查是否可以调用takePicture（）。
private boolean safeToTakePicture = false;
surfaceChanged()中，只需在调用startPreview（）后将标志设置为true：
camera.startPreview();
safeToTakePicture = true;
onClick()听众检查标志并拍照，如果可以这样做：
if (safeToTakePicture) {
mp.start();
camera.takePicture(null, null, mPicture);
safeToTakePicture = false;
}
onPictureTaken()中，在保存图片后再次将标志设置为true（并添加例外打印）：
PictureCallback mPicture = new PictureCallback() {
@Override
public void onPictureTaken(byte[] data, Camera camera) {
pictureFile = getOutputMediaFile();
camera.startPreview();
if (pictureFile == null) {
//no path to picture, return
safeToTakePicture = true;
return;
}
try {
FileOutputStream fos = new FileOutputStream(pictureFile);
fos.write(data);
fos.close();
} catch (FileNotFoundException e) {
e.printStackTrace(); //<-------- show exception
} catch (IOException e) {
e.printStackTrace(); //<-------- show exception
}
//finished saving picture
safeToTakePicture = true;
}
};
注意：正如文档所说，“必须先开始预览才能拍照。”所以可能的改进是使用setPreviewCallback（）来注册在预览数据可用时调用的回调，并将标志设置为true当onPreviewFrame被调用时。
我也有类似的问题。后来我发现startPreview非常重要。
_camera.startPreview()在takePicutre结账时点5和6 in this link非常重要。
这可能有很多原因，在我的情况下，我试图拍照没有预览（隐藏的照片），我正在使用SurfaceView，所以我用SurfaceTexture取代它
SurfaceTexture surfaceTexture = new SurfaceTexture(10);
camera.setPreviewTexture(surfaceTexture);
问题解决了...... P.S我只在6.0以上的设备上收到此错误
你忘记在相机上打电话给startPreview()了吗？
有关更多信息，请参阅here。
此方法将帮助您尝试解决问题。
private void safeCameraOpen(int id) {
try {
releaseCameraAndPreview();
mCamera = Camera.open(id);
} catch (Exception e) {
Log.e(getString(R.string.app_name), "failed to open Camera");
e.printStackTrace();
}
}
private void releaseCameraAndPreview() {
if (mCamera != null) {
mCamera.release();
mCamera = null;
}
}