declarative 宣言的，公布的，声明的
programmatically 以编程方式
coexist 同时共存，和平共处
sibling 兄弟，姐妹;[生]同科，同属;[人]氏族成员
Two-way data binding 双向数据绑定
This can also improve your app's performance and help prevent memory leaks and null pointer exceptions.
The Data Binding Library offers both flexibility and broad compatibility数据绑定库提供了灵活性和广泛的兼容性
