? ?ZXing的CaptureActivity在其他activity切换回来时会出现黑屏现象，跟踪发现surfaceDestroyed并不一定能调用到。
? ?在ZXing项目找到zxing不支持tabhost的答复。
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Project Member #1 srowenThe app doesn't use a TabHost. If you are writing your own app, indeed, you may need to write different code! this part is not a library that is supposed to work in other contexts.
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? ?虽然项目采用tabactivity搭建框架，但CaptureActivity是单独的activity。
? ?针对surfaceDestroyed在activity切换时不会总是调用的问题，https://github.com/commonsguy/cw-advandroid/tree/master/Camera/Preview/?的解决方法值的参考。
也即是把打开摄像头的动作延迟到surfaceChanged时调用。