未调用相机 onPreviewFrame

问题描述

当使用 Camera.PreviewCallback 实现时，在初始化相机并开始预览(Camera.startPrevew())后，onPreviewFrame 被毫无问题地调用.问题是，如果我使用 MediaRecorder 进行视频录制，则不会再调用 onPreviewFrame.

when using the Camera.PreviewCallback implementation the onPreviewFrame is called without problem after initializing camera and starting preview (Camera.startPrevew()). The problem is if I make a video recording using MediaRecorder onPreviewFrame does not get called any more.

我知道在使用MediaRecorder录制视频时会停止Camera.PreviewCallback，但为什么不能重新启动?

I understand that when using MediaRecorder to record video stops the Camera.PreviewCallback, but why can't it be restarted?

我已尝试重置相机预览回调 (setPreviewCallback(callback)) 并重新启动 startPreview，但是当我进行预览时，没有调用 onPreviewFrame.

I have tried resetting the camera preview callback (setPreviewCallback(callback)) and restarting startPreview, but while I have a preview there is no call to onPreviewFrame.

推荐答案

必须在surfaceChanged方法中调用setPreviewCallback，而不能只在surfaceCreated中调用.

You must call setPreviewCallback in the surfaceChanged method, not only in the surfaceCreated.

public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
if (mHolder.getSurface() == null){
  return;
}

try {
    mCamera.stopPreview();
} catch (Exception e){
  // ignore: tried to stop a non-existent preview
}

try {
    mCamera.setPreviewCallback(this);
    mCamera.setPreviewDisplay(mHolder);
    mCamera.startPreview();

} catch (Exception e){
    Log.d(TAG, "Error starting camera preview: " + e.getMessage());
}
}

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