我正在制作一款Android应用程序，我正在使用我的设备的Camera和Accelerometer。当我的设备与水平面平行时，我想自动捕捉图像，即X-Y-Z坐标等于0-0-9。
但我的应用程序崩溃并在此行上出现以下错误。
camera.takePicture(shutterCallback, rawCallback, jpegCallback);
我已经添加了我的代码和错误日志。
Java代码：
public class CamTestActivity extends Activity implements SensorEventListener{
//camera variables start//
private static final String TAG = "CamTestActivity";
Camera camera;
Activity act;
Context ctx;
// accelarometer variables start
private float lastX, lastY, lastZ;
private SensorManager sensorManager;
private Sensor accelerometer;
private float deltaX = 0;
private float deltaY = 0;
private float deltaZ = 0;
//accelarometer variables end
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ctx = this;
act = this;
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.main);
preview = new Preview(this, (SurfaceView)findViewById(R.id.surfaceView));
preview.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
((FrameLayout) findViewById(R.id.layout)).addView(preview);
preview.setKeepScreenOn(true);
//accelaromater code start
sensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
if (sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER) != null) {
// success! we have an accelerometer
accelerometer = sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
sensorManager.registerListener(this, accelerometer, SensorManager.SENSOR_DELAY_NORMAL);
} else {
// fai! we dont have an accelerometer!
}
//accelaromater end
}
@Override
public void onSensorChanged(SensorEvent event) {
// get the change of the x,y,z values of the accelerometer
deltaX = Math.abs(lastX - event.values[0]);
deltaY = Math.abs(lastY - event.values[1]);
deltaZ = Math.abs(lastZ - event.values[2]);
if (deltaX <= 0 && deltaY = 0 && deltaZ = 9) {
camera.takePicture(shutterCallback, rawCallback, jpegCallback);
}
}
@Override
public void onAccuracyChanged(Sensor sensor, int accuracy) {
}
@Override
protected void onResume() {
super.onResume();
int numCams = Camera.getNumberOfCameras();
if(numCams > 0){
try{
camera = Camera.open(0);
camera.startPreview();
preview.setCamera(camera);
} catch (RuntimeException ex){
Toast.makeText(ctx, getString(R.string.camera_not_found), Toast.LENGTH_LONG).show();
}
}
}
@Override
protected void onPause() {
if(camera != null) {
camera.stopPreview();
preview.setCamera(null);
camera.release();
camera = null;
}
super.onPause();
}
private void resetCam() {
camera.startPreview();
preview.setCamera(camera);
}
private void refreshGallery(File file) {
Intent mediaScanIntent = new Intent( Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
mediaScanIntent.setData(Uri.fromFile(file));
sendBroadcast(mediaScanIntent);
}
ShutterCallback shutterCallback = new ShutterCallback() {
public void onShutter() {
// Log.d(TAG, "onShutter'd");
}
};
PictureCallback rawCallback = new PictureCallback() {
public void onPictureTaken(byte[] data, Camera camera) {
// Log.d(TAG, "onPictureTaken - raw");
}
};
PictureCallback jpegCallback = new PictureCallback() {
public void onPictureTaken(byte[] data, Camera camera) {
new SaveImageTask().execute(data);
resetCam();
Log.d(TAG, "onPictureTaken - jpeg");
}
};
private class SaveImageTask extends AsyncTask<byte[], Void, Void> {
@Override
protected Void doInBackground(byte[]... data) {
FileOutputStream outStream = null;
// Write to SD Card
try {
File sdCard = Environment.getExternalStorageDirectory();
File dir = new File (sdCard.getAbsolutePath() + "/camtest");
dir.mkdirs();
String fileName = String.format("%d.jpg", System.currentTimeMillis());
File outFile = new File(dir, fileName);
outStream = new FileOutputStream(outFile);
outStream.write(data[0]);
outStream.flush();
outStream.close();
Log.d(TAG, "onPictureTaken - wrote bytes: " + data.length + " to " + outFile.getAbsolutePath());
refreshGallery(outFile);
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
}
return null;
}
}
}
当我尝试捕获图像时，应用程序崩溃并显示此日志
错误记录
05-04 15:23:19.307 2966-2966/com.example.cam V/InputMethodManager: onWindowFocus: null softInputMode=32 first=true flags=#10580
05-04 15:23:19.307 2966-2966/com.example.cam V/InputMethodManager: START INPUT: com.android.internal.policy.PhoneWindow$DecorView{a92340c V.E...... R.....ID 0,0-1280,720} ic=null tba=android.view.inputmethod.EditorInfo@f287027 controlFlags=#104
05-04 15:23:22.313 2966-2966/com.example.cam E/SensorManager: Exception dispatching input event.
05-04 15:23:22.313 2966-2966/com.example.cam D/AndroidRuntime: Shutting down VM
Process: com.example.cam, PID: 2966
java.lang.RuntimeException: takePicture failed
at android.hardware.Camera.native_takePicture(Native Method)
at android.hardware.Camera.takePicture(Camera.java:1833)
at android.hardware.Camera.takePicture(Camera.java:1778)
at com.example.cam.CamTestActivity.onSensorChanged(CamTestActivity.java:154)
at android.hardware.SystemSensorManager$SensorEventQueue.dispatchSensorEvent(SystemSensorManager.java:481)
at android.os.MessageQueue.nativePollOnce(Native Method)
at android.os.MessageQueue.next(MessageQueue.java:328)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:5769)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:789)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:679)