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當有人嘗試解鎖我的設備並輸入錯誤的密碼3次時，我想實現通過前置攝像頭捕捉圖像的功能。我檢查了這是可能的Android和一些應用程序也可在市場。使用密碼鎖定設備時捕捉圖像
我已經做了一些工作來實現這一點，但我得到一個黑色的圖像。下面的代碼：
註冊與設備管理員取得廣播不正確的密碼嘗試：
public class DeviceAdminSample extends DeviceAdminReceiver {
static Context ctx;
static SharedPreferences getSamplePreferences(Context context) {
ctx = context;
return context.getSharedPreferences(
DeviceAdminReceiver.class.getName(), 0);
}
@Override
public void onPasswordFailed(Context context, Intent intent) {
super.onPasswordFailed(context, intent);
System.out.println("Password Attempt is Failed...");
Intent i = new Intent(context, CameraView.class);
i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivity(i);
}
}
相機類來捕捉圖像，並將其保存到SD卡：
public class CameraView extends Activity implements SurfaceHolder.Callback,
OnClickListener {
private static final String TAG = "CameraTest";
Camera mCamera;
boolean mPreviewRunning = false;
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
Log.e(TAG, "onCreate");
setContentView(R.layout.cameraview);
mSurfaceView = (SurfaceView) findViewById(R.id.surface_camera);
// mSurfaceView.setOnClickListener(this);
mSurfaceHolder = mSurfaceView.getHolder();
mSurfaceHolder.addCallback(this);
mSurfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
mSurfaceHolder.setKeepScreenOn(true);
// mSurfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
super.onRestoreInstanceState(savedInstanceState);
}
protected void onResume() {
Log.e(TAG, "onResume");
super.onResume();
}
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
}
protected void onStop() {
Log.e(TAG, "onStop");
super.onStop();
}
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
Log.e(TAG, "surfaceChanged");
// XXX stopPreview() will crash if preview is not running
if (mPreviewRunning) {
mCamera.stopPreview();
}
Camera.Parameters p = mCamera.getParameters();
mCamera.setParameters(p);
mCamera.startPreview();
mPreviewRunning = true;
mCamera.takePicture(null, null, mPictureCallback);
}
public void surfaceDestroyed(SurfaceHolder holder) {
Log.e(TAG, "surfaceDestroyed");
// mCamera.stopPreview();
// mPreviewRunning = false;
// mCamera.release();
stopCamera();
}
private SurfaceView mSurfaceView;
private SurfaceHolder mSurfaceHolder;
public void onClick(View v) {
mCamera.takePicture(null, mPictureCallback, mPictureCallback);
}
public void surfaceCreated(SurfaceHolder holder) {
Log.e(TAG, "surfaceCreated");
int i = findFrontFacingCamera();
if (i > 0);
while (true) {
try {
this.mCamera = Camera.open(i);
try {
this.mCamera.setPreviewDisplay(holder);
return;
} catch (IOException localIOException2) {
stopCamera();
return;
}
} catch (RuntimeException localRuntimeException) {
localRuntimeException.printStackTrace();
if (this.mCamera == null)
continue;
stopCamera();
this.mCamera = Camera.open(i);
try {
this.mCamera.setPreviewDisplay(holder);
Log.d("HiddenEye Plus", "Camera open RE");
return;
} catch (IOException localIOException1) {
stopCamera();
localIOException1.printStackTrace();
return;
}
} catch (Exception localException) {
if (this.mCamera != null)
stopCamera();
localException.printStackTrace();
return;
}
}
}
private void stopCamera() {
if (this.mCamera != null) {
/*this.mCamera.stopPreview();
this.mCamera.release();
this.mCamera = null;*/
this.mPreviewRunning = false;
}
}
private int findFrontFacingCamera() {
int i = Camera.getNumberOfCameras();
for (int j = 0;; j++) {
if (j >= i)
return -1;
Camera.CameraInfo localCameraInfo = new Camera.CameraInfo();
Camera.getCameraInfo(j, localCameraInfo);
if (localCameraInfo.facing == 1)
return j;
}
}
Camera.PictureCallback mPictureCallback = new Camera.PictureCallback() {
public void onPictureTaken(byte[] data, Camera camera) {
if (data != null) {
// Intent mIntent = new Intent();
// mIntent.putExtra("image",imageData);
mCamera.stopPreview();
mPreviewRunning = false;
mCamera.release();
try {
BitmapFactory.Options opts = new BitmapFactory.Options();
Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0,
data.length, opts);
bitmap = Bitmap.createScaledBitmap(bitmap, 300, 300, false);
int width = bitmap.getWidth();
int height = bitmap.getHeight();
int newWidth = 300;
int newHeight = 300;
// calculate the scale - in this case = 0.4f
float scaleWidth = ((float) newWidth)/width;
float scaleHeight = ((float) newHeight)/height;
// createa matrix for the manipulation
Matrix matrix = new Matrix();
// resize the bit map
matrix.postScale(scaleWidth, scaleHeight);
// rotate the Bitmap
matrix.postRotate(-90);
Bitmap resizedBitmap = Bitmap.createBitmap(bitmap, 0, 0,
width, height, matrix, true);
ByteArrayOutputStream bytes = new ByteArrayOutputStream();
resizedBitmap.compress(Bitmap.CompressFormat.JPEG, 40,
bytes);
// you can create a new file name "test.jpg" in sdcard
// folder.
File f = new File(Environment.getExternalStorageDirectory()
+ File.separator + "test.jpg");
System.out.println("File F : " + f);
f.createNewFile();
// write the bytes in file
FileOutputStream fo = new FileOutputStream(f);
fo.write(bytes.toByteArray());
// remember close de FileOutput
fo.close();
} catch (Exception e) {
e.printStackTrace();
}
// StoreByteImage(mContext, imageData, 50,"ImageName");
// setResult(FOTO_MODE, mIntent);
setResult(585);
finish();
}
}
};
}
手機解鎖後，您是否測試了代碼？ – 2013-04-22 16:33:38
是的，我可以使用此代碼在手機解鎖時捕獲圖像... – 2013-04-23 04:55:38
@KrishnakantDalal：您是否檢查了Android控制檯日誌。有沒有錯誤信息？ – 2013-04-23 17:45:11