Question

我正在制作自定义相机应用。我想实现自定义预览。只有在第一次显示黑屏后才会打开预览。如果有人知道为什么请帮助我！

我的相机课程：

public class CamTestActivity extends Activity {

    private static final String TAG = "CamTestActivity";

    Preview preview;
    Camera camera;
    int cameraId;
    SurfaceView sv;

    private int rotation;

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

        requestWindowFeature(Window.FEATURE_NO_TITLE);
        getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);
        setContentView(R.layout.main);
        cameraId = Camera.CameraInfo.CAMERA_FACING_BACK;
        sv = (SurfaceView) findViewById(R.id.surfaceView);
        preview = new Preview(this, sv);

        preview.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT,
                LayoutParams.MATCH_PARENT));
        ((RelativeLayout) findViewById(R.id.layout)).addView(preview);
        preview.setKeepScreenOn(true);
        // holder = sv.getHolder();
    }

    @Override
    protected void onResume() {
        super.onResume();

        openCamera(cameraId);
    }

    public boolean openCamera(int id) {
        boolean result = false;
        cameraId = id;

        releaseCamera();
        try {
            camera = Camera.open(cameraId);
        }
        catch (Exception e) {
            e.printStackTrace();
        }
        if (camera != null) {
            try {
                setUpCamera(camera);
                camera.setErrorCallback(new ErrorCallback() {

                    @Override
                    public void onError(int error, Camera camera) {

                    }
                });
                camera.setPreviewDisplay(preview.mHolder);
                camera.startPreview();
                result = true;
            }
            catch (IOException e) {
                e.printStackTrace();
                result = false;
                releaseCamera();
            }
        }
        return result;
    }

    private void setUpCamera(Camera c) {
        Camera.CameraInfo info = new Camera.CameraInfo();
        Camera.getCameraInfo(cameraId, info);
        rotation = getWindowManager().getDefaultDisplay().getRotation();
        int degree = 0;
        switch (rotation) {
            case Surface.ROTATION_0:
                degree = 0;
                break;
            case Surface.ROTATION_90:
                degree = 90;
                break;
            case Surface.ROTATION_180:
                degree = 180;
                break;
            case Surface.ROTATION_270:
                degree = 270;
                break;

            default:
                break;
        }

        if (info.facing == Camera.CameraInfo.CAMERA_FACING_FRONT) {
            // frontFacing
            rotation = (info.orientation + degree) % 330;
            rotation = (360 - rotation) % 360;
        }
        else {
            // Back-facing
            rotation = (info.orientation - degree + 360) % 360;
        }
        c.setDisplayOrientation(rotation);
        Parameters params = c.getParameters();

        // showFlashButton(params);

        List<String> focusModes = params.getSupportedFlashModes();
        if (focusModes != null) {
            if (focusModes
                    .contains(Camera.Parameters.FOCUS_MODE_CONTINUOUS_PICTURE)) {
                params.setFlashMode(Camera.Parameters.FOCUS_MODE_CONTINUOUS_PICTURE);
            }
        }

        params.setRotation(rotation);
    }

    private void releaseCamera() {
        try {
            if (camera != null) {
                camera.setPreviewCallback(null);
                camera.setErrorCallback(null);
                camera.stopPreview();
                camera.release();
                camera = null;
            }
        }
        catch (Exception e) {
            e.printStackTrace();
            Log.e("error", e.toString());
            camera = null;
        }
    }
}

Answer 1

好像你忘了放开你的相机。

将releaseCamera添加到onPause

@Override
protected void onPause() {
    releaseCamera();
    super.onPause();
}

如何在android中为相机创建自定义预览

1 个答案: