Question

我的应用程序在很多设备上打开/关闭闪存。但它不适用于LG-F500S Android版本6.0（三星S7 android 6.0工作正常）。谁能帮我找到理由和解决方案呢？

Answer 1

我必须找到理由 + targetSdkVersion＆lt; 23个
+表面支架：

public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {

    private SurfaceHolder mHolder;
    private Camera mCamera;
    public CameraPreview(Context context, Camera camera) {
        super(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);
    }


    @Override
    public void surfaceCreated(SurfaceHolder surfaceHolder) {
        try {
            mCamera.setPreviewDisplay(surfaceHolder);
            mCamera.startPreview();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    @Override
    public void surfaceChanged(SurfaceHolder surfaceHolder, int i, int i1, int i2) {
        if (mHolder.getSurface() == null){
            // preview surface does not exist
            return;
        }
        try {
            mCamera.stopPreview();
        } catch (Exception e){
            e.printStackTrace();
        }
        try {
            mCamera.setPreviewDisplay(mHolder);
            mCamera.startPreview();

        } catch (Exception e){
            e.printStackTrace();
        }
    }

    @Override
    public void surfaceDestroyed(SurfaceHolder surfaceHolder) {

    }
}

+ MainActivity：

public Camera getCameraInstance(){
        Camera c = null;
        try {
            c = Camera.open(); // attempt to get a Camera instance
        }
        catch (Exception e){
            // Camera is not available (in use or does not exist)
        }
        return c; // returns null if camera is unavailable
    }
 @Override
    protected void onResume() {
        super.onResume();
        cam = getCameraInstance();
        mPreview = new CameraPreview(this, cam);
        FrameLayout preview = (FrameLayout) findViewById(R.id.surfaceContain);
        preview.addView(mPreview);


    }
public void toggleLight(View v){
        if (isFlash){
            isFlash = false;
            params = cam.getParameters();
            params.setFlashMode(Camera.Parameters.FLASH_MODE_OFF);
            cam.setParameters(params);
            cam.startPreview();
        }else{
            isFlash = true;
            params = cam.getParameters();
            params.setFlashMode(Camera.Parameters.FLASH_MODE_TORCH);
            cam.setParameters(params);
            cam.startPreview();
        }
    }

在此处查看详细信息：
https://developer.android.com/guide/topics/media/camera.html

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