切换相机崩溃Android

Question

I have a class called CameraHelper, when I try to switch camera from front to back on the click of a button, in one smooth transition. My application freezes when I call this class - I know I'm not doing something right. Can anyone help me out here?

Any help is much appreciated.

public class CameraHelper {
    private final CameraHelperImpl mImpl;

    public CameraHelper(final Context context) {
        if (SDK_INT >= GINGERBREAD) {
            mImpl = new CameraHelperGB();
        } else {
            mImpl = new CameraHelperBase(context);
        }
    }

    public interface CameraHelperImpl {
        int getNumberOfCameras();

        Camera openCamera(int id);

        Camera openDefaultCamera();

        Camera openCameraFacing(int facing);

        boolean hasCamera(int cameraFacingFront);

        void getCameraInfo(int cameraId, CameraInfo2 cameraInfo);
    }

    public int getNumberOfCameras() {
        return mImpl.getNumberOfCameras();
    }

    public Camera openCamera(final int id) {
        return mImpl.openCamera(id);
    }

    public Camera openDefaultCamera() {
        return mImpl.openDefaultCamera();
    }

    public Camera openFrontCamera() {
        return mImpl.openCameraFacing(CameraInfo.CAMERA_FACING_FRONT);
    }

    public Camera openBackCamera() {
        return mImpl.openCameraFacing(CameraInfo.CAMERA_FACING_BACK);
    }

    public boolean hasFrontCamera() {
        return mImpl.hasCamera(CameraInfo.CAMERA_FACING_FRONT);
    }

    public boolean hasBackCamera() {
        return mImpl.hasCamera(CameraInfo.CAMERA_FACING_BACK);
    }

    public void getCameraInfo(final int cameraId, final CameraInfo2 cameraInfo) {
        mImpl.getCameraInfo(cameraId, cameraInfo);
    }

    public void setCameraDisplayOrientation(final Activity activity,
            final int cameraId, final Camera camera) {
        int result = getCameraDisplayOrientation(activity, cameraId);
        camera.setDisplayOrientation(result);
    }

    public int getCameraDisplayOrientation(final Activity activity, final int cameraId) {
        int rotation = activity.getWindowManager().getDefaultDisplay()
                .getRotation();
        int degrees = 0;
        switch (rotation) {
            case Surface.ROTATION_0:
                degrees = 0;
                break;
            case Surface.ROTATION_90:
                degrees = 90;
                break;
            case Surface.ROTATION_180:
                degrees = 180;
                break;
            case Surface.ROTATION_270:
                degrees = 270;
                break;
        }

        int result;
        CameraInfo2 info = new CameraInfo2();
        getCameraInfo(cameraId, info);
        if (info.facing == Camera.CameraInfo.CAMERA_FACING_FRONT) {
            result = (info.orientation + degrees) % 360;
        } else { // back-facing
            result = (info.orientation - degrees + 360) % 360;
        }
        return result;
    }

    public static class CameraInfo2 {
        public int facing;
        public int orientation;
    }
} 

Answer 1

private void switchBackToFrontCamera(int frontCamId) {

    if (camera != null) {
        camera.stopPreview();
        camera.release();
        camera= null;
    }

    camera= Camera.open(frontCamId);

    if (camera != null) {
        try {
            camera.setPreviewDisplay(mSurfaceView.getHolder());
            camera.startPreview();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}