Android使用JetPack入门实例
概念Android最流行框架-JetPack，采用MVVM的设计模式，数据流如下图所示。程序实例gradle添加依赖androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'implementation "androidx.lifecycle:lifecycle-extensions:$lifecycle_version"MainActivity.javapublic class MainAc
