当用户将输入错误的密码时，我正在开发一个从前置摄像头拍摄照片的应用程序。我做了一些事情，比如捕获错误密码和捕获图像的事件。但是我的代码会捕获黑色图像。
我已对此进行了研究，发现由于隐私原因，无法在没有预览或没有用户互动的情况下捕获图像。 但是市场上有一些Intruder Selfie应用可以做到这一点。那怎么做呢？
这是 Admin.java ： -
public class Admin extends DeviceAdminReceiver {
public static int pass_failed_count = 0;
Context conn;
private Camera camera; // camera object
// private TextView TimeLeft; // time left field
File mediaFile;
private static final String IMAGE_DIRECTORY_NAME = "Captured_Images";
int numberOfCameras;
// private TextView cameras;
void showToast(Context context, CharSequence msg) {
Toast.makeText(context, msg, Toast.LENGTH_SHORT).show();
}
@Override
public void onEnabled(Context context, Intent intent) {
showToast(context, "Device Administrator: Activated");
}
@Override
public CharSequence onDisableRequested(Context context, Intent intent) {
return "This is an optional message to warn the user about disabling.";
}
@Override
public void onDisabled(Context context, Intent intent) {
showToast(context, "Device Administrator: Deactivated");
}
public Admin(Context con) {
this.conn = con;
}
public Admin() {
}
@Override
public void onPasswordFailed(Context context, Intent intent) {
pass_failed_count++;
showToast(context, "Sample Device Admin: pw failed");
Vibrator v = (Vibrator)context.getSystemService(context.VIBRATOR_SERVICE);
// Vibrate for 2 seconds
v.vibrate(2000);
Intent i = new Intent(conn, CameraView.class);
conn.startActivity(i);
/* if (mHiddenCameraFragment != null) { //Remove fragment from container if present
getSupportFragmentManager()
.beginTransaction()
.remove(mHiddenCameraFragment)
.commit();
mHiddenCameraFragment = null;
}
startService(new Intent(context, DemoCamService.class));*/
}
@Override
public void onPasswordSucceeded(Context context, Intent intent) {
showToast(context, "Welcome Device Owner");
}
}
以下是我想要调用onPasswordFailed的服务： -
public class DemoCamService extends HiddenCameraService {
@Nullable
@Override
public IBinder onBind(Intent intent) {
return null;
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.CAMERA) == PackageManager.PERMISSION_GRANTED) {
if (HiddenCameraUtils.canOverDrawOtherApps(this)) {
CameraConfig cameraConfig = new CameraConfig()
.getBuilder(this)
.setCameraFacing(CameraFacing.FRONT_FACING_CAMERA)
.setCameraResolution(CameraResolution.MEDIUM_RESOLUTION)
.setImageFormat(CameraImageFormat.FORMAT_JPEG)
.build();
startCamera(cameraConfig);
new android.os.Handler().postDelayed(new Runnable() {
@Override
public void run() {
takePicture();
}
}, 2000);
} else {
//Open settings to grant permission for "Draw other apps".
HiddenCameraUtils.openDrawOverPermissionSetting(this);
}
} else {
//TODO Ask your parent activity for providing runtime permission
Toast.makeText(this, "Camera permission not available", Toast.LENGTH_SHORT).show();
}
return START_NOT_STICKY;
}
@Override
public void onImageCapture(@NonNull File imageFile) {
BitmapFactory.Options options = new BitmapFactory.Options();
options.inPreferredConfig = Bitmap.Config.RGB_565;
Bitmap bitmap = BitmapFactory.decodeFile(imageFile.getAbsolutePath(), options);
//Do something with the bitmap
saveImage(bitmap,"service");
Log.d("Image capture", imageFile.length() + "");
stopSelf();
}
private void saveImage(Bitmap finalBitmap, String image_name) {
String root = Environment.getExternalStorageDirectory().toString();
File myDir = new File(root);
myDir.mkdirs();
String fname = "Image-" + image_name+ ".jpg";
File file = new File(myDir, fname);
if (file.exists()) file.delete();
Log.i("LOAD", root + fname);
try {
FileOutputStream out = new FileOutputStream(file);
finalBitmap.compress(Bitmap.CompressFormat.JPEG, 90, out);
out.flush();
out.close();
} catch (Exception e) {
e.printStackTrace();
}
}
@Override
public void onCameraError(@CameraError.CameraErrorCodes int errorCode) {
switch (errorCode) {
case CameraError.ERROR_CAMERA_OPEN_FAILED:
//Camera open failed. Probably because another application
//is using the camera
Toast.makeText(this, "Cannot open camera.", Toast.LENGTH_LONG).show();
break;
case CameraError.ERROR_IMAGE_WRITE_FAILED:
//Image write failed. Please check if you have provided WRITE_EXTERNAL_STORAGE permission
Toast.makeText(this, "Cannot write image captured by camera.", Toast.LENGTH_LONG).show();
break;
case CameraError.ERROR_CAMERA_PERMISSION_NOT_AVAILABLE:
//camera permission is not available
//Ask for the camera permission before initializing it.
Toast.makeText(this, "Camera permission not available.", Toast.LENGTH_LONG).show();
break;
case CameraError.ERROR_DOES_NOT_HAVE_OVERDRAW_PERMISSION:
//Display information dialog to the user with steps to grant "Draw over other app"
//permission for the app.
HiddenCameraUtils.openDrawOverPermissionSetting(this);
break;
case CameraError.ERROR_DOES_NOT_HAVE_FRONT_CAMERA:
Toast.makeText(this, "Your device does not have front camera.", Toast.LENGTH_LONG).show();
break;
}
stopSelf();
}
}
CameraView活动： -
通过使用此活动和一些额外的课程，我能够点击照片。 我也可以点击服务按钮上的点击照片。但两个时间设备都处于解锁状态。 我想在设备锁定且用户输入错误密码时执行此操作。
public class CameraView extends AppCompatActivity
{
//a variable to store a reference to the Image View at the main.xml file
// private ImageView iv_image;
//a variable to store a reference to the Surface View at the main.xml file
private SurfaceView sv;
//a bitmap to display the captured image
private Bitmap bmp;
//Camera variables
//a surface holder
private SurfaceHolder sHolder;
//a variable to control the camera
private Camera mCamera;
//the camera parameters
private Camera.Parameters parameters;
private HiddenCameraFragment mHiddenCameraFragment;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_camera_view);
if (mHiddenCameraFragment != null) { //Remove fragment from container if present
getSupportFragmentManager()
.beginTransaction()
.remove(mHiddenCameraFragment)
.commit();
mHiddenCameraFragment = null;
}
startService(new Intent(CameraView.this, DemoCamService.class));
findViewById(R.id.btn_using_activity).setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if (mHiddenCameraFragment != null) { //Remove fragment from container if present
getSupportFragmentManager()
.beginTransaction()
.remove(mHiddenCameraFragment)
.commit();
mHiddenCameraFragment = null;
}
startActivity(new Intent(CameraView.this, DemoCamActivity.class));
}
});
findViewById(R.id.btn_using_service).setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if (mHiddenCameraFragment != null) { //Remove fragment from container if present
getSupportFragmentManager()
.beginTransaction()
.remove(mHiddenCameraFragment)
.commit();
mHiddenCameraFragment = null;
}
startService(new Intent(CameraView.this, DemoCamService.class));
}
});
findViewById(R.id.btn_using_fragment).setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
mHiddenCameraFragment = new DemoCamFragment();
getSupportFragmentManager()
.beginTransaction()
.replace(R.id.fragment_container, mHiddenCameraFragment)
.commit();
}
});
}
@Override
public void onBackPressed() {
if (mHiddenCameraFragment != null) { //Remove fragment from container if present
getSupportFragmentManager()
.beginTransaction()
.remove(mHiddenCameraFragment)
.commit();
mHiddenCameraFragment = null;
}else { //Kill the activity
super.onBackPressed();
}
}
}
那么，如何从DeviceAdminReceiver中的OnPasswordFailed调用活动或服务？