java - Android PictureCallback需要先执行然后继续其他代码

Question

我有可以拍摄照片的代码，但是在它到达 PictureCallback() 后，它会继续按代码方式运行，最终在获得字节数组之前执行其他代码。有什么办法可以阻止这种情况吗？它只需要几毫秒，而且我不介意停止 UI 线程。

private static byte[] patronImage;
.
.
.
takePatronPicture();
//I want to do something with patronImage here, but the next line
//gets executed almost immediately while getJpegCallback is still
//doing its thing.
code that does something with patronImage;
.
.
.
public void takePatronPicture(){
        if (camera != null) {
            try {
              SurfaceView surfaceView = (SurfaceView)getView().findViewById(R.id.surfaceView1);
              camera.setPreviewDisplay(surfaceView.getHolder());    
              camera.startPreview(); 
              camera.takePicture(null, null, getJpegCallback);  
            }
            catch(Exception e) {
                e.printStackTrace();
            }          
        }
    }

    final PictureCallback getJpegCallback = new PictureCallback() {
        @Override
        public void onPictureTaken(byte[] data, Camera camera) {
            try {  
                patronImage = data;

                camera.release();
                camera = null;
            } catch (final Exception e) {
                e.printStackTrace();
            }
        }
    };

Answer 1

回调的目的是在完成后它会调用您。如果您要运行需要操作数据的其他代码，请将其放入回调中。您不会卡住当前线程来等待它。事实上，如果操作将事件发送到主线程的循环程序，这样做可能会导致死锁。