Question

我正在尝试使用SurfaceView创建相机预览，它大部分工作正常。我在onSurfaceCreated方法上初始化相机并在onSurfaceDestroyed上销毁它。为什么在设备方向改变时调用上述方法。以下是表面视图代码。

@Override
public void surfaceCreated(SurfaceHolder holder) {
    // Initialize the camera
    initCamera();
    Log.d("tags", "Camera Started!");
}

@Override
public void surfaceDestroyed(SurfaceHolder holder) {
    if (camera != null) {
        camera.stopPreview();
        camera.release();
    }
    Log.d("tags", "Camera destroyed!");
}

public void initCamera() {
    if (camera == null) {
        camera = Camera.open(); // Get's the first camera
    }

    try {
        camera.setPreviewDisplay(sfHolder);
    } catch (IOException err) {
        err.printStackTrace();
    }

    // Set camera orientation
    Activity activity = (Activity)this.getContext();
    this.setCameraDisplayOrientation(activity);

    camera.startPreview();
}

private void setCameraDisplayOrientation(Activity activity) {

    Camera.CameraInfo info = new Camera.CameraInfo();
    Camera.getCameraInfo(cameraId, info);

    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;
    if (info.facing == Camera.CameraInfo.CAMERA_FACING_FRONT) {
        result = (info.orientation + degrees) % 360;
        result = (360 - result) % 360;  // compensate the mirror
    } else {  // back-facing
        result = (info.orientation - degrees + 360) % 360;
    }

    Log.d("tag", "Result -- " + result);
    boolean camNull = camera == null;
    Log.d("tag", String.valueOf(camNull));

    camera.setDisplayOrientation(result);

当我在设备上启动应用程序时，预览会按预期启动，但是当我将方向从纵向更改为横向，反之亦然时，预览会挂起几秒钟，并且新预览会显示更改的方向。 / p>

根据日志，当方向改变时，表面被破坏并再次创建，因此每次方向改变时都会重新初始化摄像机。我怎么能克服这个？我在这里做错了吗？

方向更改时相机滞后

0 个答案: