Android common controls
1.1 One of Android's common controls - Camera
https://blog.csdn.net/amoscxy/article/details/79117522
1.2 One of Android's common controls - ImageView
https://blog.csdn.net/amoscxy/article/details/80144381
1.3 Android Common Controls - ProgressBar
https://blog.csdn.net/amoscxy/article/details/80144645
1.4 Android Common Controls - AlertDialog
https://blog.csdn.net/amoscxy/article/details/80144662