Android 组件学习项目
https://www.jianshu.com/p/2ebf802f7e78?utm_campaign=maleskine&utm_content=note&utm_medium=seo_notes&utm_source=recommendation https://www.jianshu.com/p/99212c2e0308
https://www.jianshu.com/p/81d0bcb282cb
https://www.runoob.com/w3cnote/android-tutorial-linearlayout.html