Question

我试图在Android中打开Nexus5闪光灯，但我在logcat中发现了一个错误。是否可以打开它？

我的代码在这里：

活动Java

public class MainActivity extends Activity {
    Camera camera;
    Parameters parameters;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        final Switch switch1 = (Switch) findViewById(R.id.switch1);

        switch1.setOnCheckedChangeListener(new OnCheckedChangeListener() {

            @Override
            public void onCheckedChanged(CompoundButton arg0, boolean arg1) {
                // TODO Auto-generated method stub
                if (switch1.isChecked()) {

                    camera = Camera.open();
                    parameters = camera.getParameters();
                    parameters.setFlashMode(Parameters.FLASH_MODE_ON);
                    camera.setParameters(parameters);
                    Toast.makeText(getApplicationContext(),
                            "Turning on FlashLight..", Toast.LENGTH_LONG)
                            .show();

                } else {

                    parameters.setFlashMode(Parameters.FLASH_MODE_OFF);
                    camera.setParameters(parameters);
                    camera.release();
                    camera = null;
                    Toast.makeText(getApplicationContext(),
                            "Turning off FlashLight..", Toast.LENGTH_LONG)
                            .show();

                }
            }
        });
    }

}

我正在使用这些权限。

  <uses-permission android:name="android.permission.CAMERA" />
  <uses-feature android:name="android.hardware.camera" />
  <uses-permission android:name="android.permission.FLASHLIGHT"/>
  <uses-feature android:name="android.hardware.camera.flash" />
  <uses-feature android:name="android.hardware.camera.autofocus" /> 

   05-07 10:08:26.970: W/CameraBase(19606): An error occurred while connecting to camera: 0
   05-07 10:08:26.970: D/AndroidRuntime(19606): Shutting down VM
   05-07 10:08:26.970: W/dalvikvm(19606): threadid=1: thread exiting with uncaught exception (group=0x41682ba8)
   05-07 10:08:26.970: E/AndroidRuntime(19606): FATAL EXCEPTION: main
   05-07 10:08:26.970: E/AndroidRuntime(19606): Process: com.systelligence.androidflashlight, PID: 19606
   05-07 10:08:26.970: E/AndroidRuntime(19606): java.lang.RuntimeException: Unable to start activity    ComponentInfo{com.systelligence.androidflashlight/com.systelligence.androidflashlight.MainActivity}: java.lang.RuntimeException: Fail to connect to camera service
    05-07 10:08:26.970: E/AndroidRuntime(19606):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
    05-07 10:08:26.970: E/AndroidRuntime(19606):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
    05-07 10:08:26.970: E/AndroidRuntime(19606):    at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:3738)
    05-07 10:08:26.970: E/AndroidRuntime(19606):    at android.app.ActivityThread.access$900(ActivityThread.java:135)
    05-07 10:08:26.970: E/AndroidRuntime(19606):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1202)
    05-07 10:08:26.970: E/AndroidRuntime(19606):    at android.os.Handler.dispatchMessage(Handler.java:102)
     05-07 10:08:26.970: E/AndroidRuntime(19606):   at android.os.Looper.loop(Looper.java:136)

Answer 1

我会使用以下代码。在我的Nexus手机上完美运行。我需要实现SurfaceView来实现这个目标：

public class ConcertFragment extends Fragment implements SurfaceHolder.Callback {

ToggleButton btnFlashlight;
View rootView;
private Camera cam;
private boolean hasFlash;
boolean hasCamera;
boolean isFlashOn;

@Override
public void onStart() {
    super.onStart();
    SurfaceView preview = (SurfaceView)getView().findViewById(R.id.background);
    SurfaceHolder mHolder = preview.getHolder();
    mHolder.addCallback(this);
}

@Override
public void onPause(){
    super.onPause();
    turnOffFlash();
}

@Override
public void onActivityCreated(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState); 
    getCamera();
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

    rootView = inflater.inflate(R.layout.fragment_concert, container, false);

    hasFlash = getActivity().getApplicationContext().getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA_FLASH);

    if (!hasFlash) {
        // device doesn't support flash
        // Show alert message and close the application
        AlertDialog alert = new AlertDialog.Builder(getActivity()).create();

        alert.setTitle("No Flash");
        alert.setMessage("Sorry, device is not flash supported.");
        alert.setButton(DialogInterface.BUTTON_POSITIVE, "OK", new android.content.DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {

            }
        });
        alert.show();
    }
    btnFlashlight = (ToggleButton) rootView.findViewById(R.id.toggleButton);
        btnFlashlight.setOnCheckedChangeListener(new OnCheckedChangeListener() {

            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                if (isFlashOn) {
                    // turn off flash
                    turnOffFlash();
                } else {
                    // turn on flash
                    turnOnFlash();
                }
            }
        });
    return rootView;
}

private void turnOnFlash() {
    if (!isFlashOn) {
        if (cam == null || params == null) {
            return;
        }

        params = cam.getParameters();
        params.setFlashMode(Parameters.FLASH_MODE_TORCH);
        cam.setParameters(params);
        cam.startPreview();
        isFlashOn = true;
    }
}

private void turnOffFlash() {
    if (isFlashOn) {
        if (cam == null || params == null) {
            return;
        }

        params = cam.getParameters();
        params.setFlashMode(Parameters.FLASH_MODE_OFF);
        cam.setParameters(params);
        cam.stopPreview();
        cam.release();
        isFlashOn = false;
    }
}

// Get the camera
   private void getCamera() {
        if (cam != null) {
            try {
                cam = Camera.open();
                params = cam.getParameters();
                cam.startPreview();
                hasCamera = true;

            } catch (RuntimeException e) {
                Log.e("Camera Error. Failed to Open. Error: ", e.getMessage());
            }
        }
   }   

@Override
public void surfaceChanged(SurfaceHolder holder,int format,int width,int height)   {

}

@Override
public void surfaceDestroyed(SurfaceHolder holder) {
    if (cam != null) {
        cam.stopPreview();
        cam.setPreviewCallback(null);
        cam.release();
        cam = null;
        btnFlashlight.setChecked(false);
    }
}

@Override
public void surfaceCreated(SurfaceHolder holder) {
    if (cam == null) {
        cam = Camera.open();
        params = cam.getParameters();
        try {
            cam.setPreviewDisplay(holder);
        } catch (IOException e) {
            cam.release();
            cam = null;
        }
    }
}

Nexus5 Flash Light问题？

1 个答案: