我正试图在surfaceview的ontouchevent中捕捉一个图像。但是，每次触摸屏幕时，应用程序都会崩溃，出现以下异常：
01-05 21:03:18.500: ERROR/AndroidRuntime(10367): FATAL EXCEPTION: main
java.lang.RuntimeException: takePicture failed
at android.hardware.Camera.native_takePicture(Native Method)
at android.hardware.Camera.takePicture(Camera.java:1126)
at android.hardware.Camera.takePicture(Camera.java:1071)
at com.test.MotionDetector.CameraSurfaceView.onTouchEvent(CameraSurfaceView.java:107)
at android.view.View.dispatchTouchEvent(View.java:7350)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2470)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2212)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2470)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2212)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2470)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2212)
at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:2151)
at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1480)
at android.app.Activity.dispatchTouchEvent(Activity.java:2469)
at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:2099)
at android.view.View.dispatchPointerEvent(View.java:7535)
at android.view.ViewRootImpl.deliverPointerEvent(ViewRootImpl.java:3492)
at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:3424)
at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:4534)
at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:4512)
at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:4616)
at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:171)
at android.os.MessageQueue.nativePollOnce(Native Method)
at android.os.MessageQueue.next(MessageQueue.java:125)
at android.os.Looper.loop(Looper.java:124)
at android.app.ActivityThread.main(ActivityThread.java:4921)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1038)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:805)
at dalvik.system.NativeStart.main(Native Method)
我的代码：
package com.nadim.MotionDetector;
import android.content.Context;
import android.hardware.Camera;
import android.os.Environment;
import android.util.Log;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.widget.Toast;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
public class CameraSurfaceView extends SurfaceView implements SurfaceHolder.Callback {
private SurfaceHolder mHolder;
private Camera mCamera;
private Context context;
public CameraSurfaceView(Context context, Camera camera) {
super(context);
this.context = context;
mCamera = camera;
// Install a SurfaceHolder.Callback so we get notified when the
// underlying surface is created and destroyed.
mHolder = getHolder();
mHolder.addCallback(this);
// deprecated setting, but required on Android versions prior to 3.0
mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
public void surfaceCreated(SurfaceHolder holder) {
// The Surface has been created, now tell the camera where to draw the preview.
try {
mCamera.setPreviewDisplay(holder);
mCamera.startPreview();
} catch (IOException e) {
Log.d("MotionDetector", "Error setting camera preview: " + e.getMessage());
}
}
public void surfaceDestroyed(SurfaceHolder holder) {
// empty. Take care of releasing the Camera preview in your activity.
}
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
// If your preview can change or rotate, take care of those events here.
// Make sure to stop the preview before resizing or reformatting it.
if (mHolder.getSurface() == null) {
// preview surface does not exist
return;
}
// stop preview before making changes
try {
mCamera.stopPreview();
} catch (Exception e) {
// ignore: tried to stop a non-existent preview
}
// set preview size and make any resize, rotate or
// reformatting changes here
// start preview with new settings
try {
mCamera.setPreviewDisplay(mHolder);
mCamera.startPreview();
} catch (Exception e) {
Log.d("MotionDetector", "Error starting camera preview: " + e.getMessage());
}
}
@Override
public boolean onTouchEvent(MotionEvent event) {
Toast.makeText(context, "Picture taken", Toast.LENGTH_SHORT).show();
//System.gc(); tried this because it was suggested in a stackoverflow question but it didn't help.
mCamera.takePicture(null, mPicture, mPicture);
return true; //processed
}
private Camera.PictureCallback mPicture = new Camera.PictureCallback() {
@Override
public void onPictureTaken(byte[] data, Camera camera) {
File pictureFile = getOutputMediaFile();
if (pictureFile == null) {
return;
}
try {
FileOutputStream fos = new FileOutputStream(pictureFile);
fos.write(data);
fos.close();
} catch (FileNotFoundException e) {
Log.d("MotionDetector", "File not found: " + e.getMessage());
} catch (IOException e) {
Log.d("MotionDetector", "Error accessing file: " + e.getMessage());
}
}
};
private static File getOutputMediaFile() {
File mediaStorageDir = new File(Environment.getExternalStorageDirectory(), "motiondetect");
if (!mediaStorageDir.exists()) {
if (!mediaStorageDir.mkdirs()) {
Log.d("MyCameraApp", "failed to create directory");
return null;
}
}
// Create a media file name
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
File mediaFile;
mediaFile = new File(mediaStorageDir, timeStamp + ".jpg");
return mediaFile;
}
}
使用的权限和功能：
<uses-permission android:name="android.permission.CAMERA"/>
<uses-feature android:name="android.hardware.camera"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-feature android:name="android.hardware.camera.autofocus" />
<uses-feature android:name="android.hardware.camera.flash" />
我不知道为什么会发生车祸。许多其他主题建议首先调用camera.startpreview。我这么做了，但解决不了问题。
拍照前的猫：
01-05 21:45:57.667: WARN/ActivityManager(754): No content provider found for permission revoke: file:///data/local/tmp/com.test.MotionDetector
01-05 21:45:57.667: WARN/ActivityManager(754): No content provider found for permission revoke: file:///data/local/tmp/com.test.MotionDetector
01-05 21:45:57.687: INFO/ActivityManager(754): Force stopping com.test.MotionDetector appid=10103 user=-1: uninstall pkg
01-05 21:45:57.687: INFO/ActivityManager(754): Killing 4264:com.test.MotionDetector/u0a103 (adj 7): stop com.test.MotionDetector
01-05 21:45:57.687: INFO/ActivityManager(754): Force finishing activity ActivityRecord{437a6678 u0 com.test.MotionDetector/.MotionDetectActivity t144}
01-05 21:45:57.697: WARN/InputDispatcher(754): channel '42adff40 com.test.MotionDetector/com.test.MotionDetector.MotionDetectActivity (server)' ~ Consumer closed input channel or an error occurred. events=0x9
01-05 21:45:57.697: ERROR/InputDispatcher(754): channel '42adff40 com.test.MotionDetector/com.test.MotionDetector.MotionDetectActivity (server)' ~ Channel is unrecoverably broken and will be disposed!
01-05 21:45:57.697: WARN/InputDispatcher(754): Attempted to unregister already unregistered input channel '42adff40 com.test.MotionDetector/com.test.MotionDetector.MotionDetectActivity (server)'
01-05 21:45:57.697: INFO/WindowState(754): WIN DEATH: Window{42adff40 u0 com.test.MotionDetector/com.test.MotionDetector.MotionDetectActivity}
01-05 21:45:57.757: INFO/PackageManager(754): Running dexopt on: com.test.MotionDetector
01-05 21:45:57.757: INFO/PackageManager(754): Package com.test.MotionDetector codePath changed from /data/app/com.test.MotionDetector-1.apk to /data/app/com.test.MotionDetector-2.apk; Retaining data and using new
01-05 21:45:57.807: INFO/ActivityManager(754): Force stopping com.test.MotionDetector appid=10103 user=-1: update pkg
01-05 21:45:57.807: WARN/PackageManager(754): Code path for pkg : com.test.MotionDetector changing from /data/app/com.test.MotionDetector-1.apk to /data/app/com.test.MotionDetector-2.apk
01-05 21:45:57.807: WARN/PackageManager(754): Resource path for pkg : com.test.MotionDetector changing from /data/app/com.test.MotionDetector-1.apk to /data/app/com.test.MotionDetector-2.apk
01-05 21:45:57.937: INFO/ActivityManager(754): Force stopping com.test.MotionDetector appid=10103 user=0: pkg removed
01-05 21:45:57.987: DEBUG/BackupManagerService(754): Received broadcast Intent { act=android.intent.action.PACKAGE_REMOVED dat=package:com.test.MotionDetector flg=0x4000010 (has extras) }
01-05 21:45:58.047: DEBUG/BackupManagerService(754): Received broadcast Intent { act=android.intent.action.PACKAGE_ADDED dat=package:com.test.MotionDetector flg=0x4000010 (has extras) }
01-05 21:45:58.567: INFO/Icing.InternalIcingCorporaProvider(12750): Updating corpora: A: com.test.MotionDetector, C: MAYBE
01-05 21:45:58.647: DEBUG/PackageAddedReceiver(1086): package added com.test.MotionDetector
01-05 21:45:58.737: INFO/ActivityManager(754): START u0 {flg=0x10000000 cmp=com.test.MotionDetector/.MotionDetectActivity} from pid 4578
01-05 21:45:58.777: INFO/ActivityManager(754): Start proc com.test.MotionDetector for activity com.test.MotionDetector/.MotionDetectActivity: pid=4630 uid=10103 gids={50103, 1028, 1015}
01-05 21:45:59.627: INFO/ActivityManager(754): Displayed com.test.MotionDetector/.MotionDetectActivity: +861ms (total +972ms)
01-05 21:45:59.657: INFO/WindowManager(754): Screen frozen for +869ms due to Window{43cb77a8 u0 com.test.MotionDetector/com.test.MotionDetector.MotionDetectActivity}
最佳答案
假设您希望保存jpeg，则不需要原始回调，因此
将调用更改为takePicture（），从：
mCamera.takePicture(null, mPicture, mPicture);
到
mCamera.takePicture(null, null, mPicture);
在ontouchevent（）中。这将使用JPEG图片回调。
调用takePicture（）也会导致预览停止，因此如果要拍摄更多照片或重新启动预览，可能需要在onPictureTaken（）回调中再次调用startPreview（）。
另外，在ontouchevent（）中，您可能会得到多个事件，因此请筛选适合您的事件：
@Override
public boolean onTouchEvent(MotionEvent event) {
Toast.makeText(context, "Picture taken", Toast.LENGTH_SHORT).show();
//System.gc(); tried this because it was suggested in a stackoverflow question but it didn't help.
switch(event.getAction()) {
case MotionEvent.ACTION_DOWN:
// A pressed gesture has started, the motion contains the initial starting location
break;
case MotionEvent.ACTION_UP:
// A pressed gesture has finished, the motion contains the final release location
// as well as any intermediate points since the last down or move event.
mCamera.takePicture(null, mPicture, mPicture);
break;
default:
break;
}
return true; //processed
}
如果您将takePicture（）放在action_down中，则触摸屏幕时将立即调用它，而在action_up中，则会在移除手指时调用它。看看哪个适合你。