看到这些博客的时候,相信小伙伴们已经看了不少的有关于Android Jetpack的知识了,关于Jetpack的原理,有些文章讲的很好,这里就不重复了,此系列的博客,旨在通过一些很简单的小demo,和大家一起熟悉最基本的用法~
Android Jetpack -- Lifecycle
Android Jetpack -- ViewModel & LiveData
Android Jetpack -- paging & room
Android Jetpack -- navigation
项目git地址:https://github.com/zhangtiansimple/jetpack_demo
------------------------------------------------------------------------------------------------------------------------
Navigation的引入在一定程度上优化了传统的对于Fragment的控制,接下来看看Navigation的使用。
首先建立三个Fragment和它们的布局文件
class Fragment1 : Fragment() {
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
return inflater.inflate(R.layout.fragment1, container, false)
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
btn.setOnClickListener { Navigation.findNavController(it).navigate(R.id.action_page2) }
}
}
class Fragment2 : Fragment() {
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
return inflater.inflate(R.layout.fragment2, container, false)
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
btn_return.setOnClickListener { Navigation.findNavController(it).navigateUp() }
btn_go.setOnClickListener { Navigation.findNavController(it).navigate(R.id.action_page3) }
}
}
class Fragment3 : Fragment() {
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
return inflater.inflate(R.layout.fragment3, container, false)
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
//点击返回page2
btn.setOnClickListener { Navigation.findNavController(it).navigateUp() }
}
}
接着在res资源目录下建立navigation路径,并且建立nav_graph.xml文件,xml文件里配置了fragment的行为关系
最后是Activity,在Activity的布局文件里引入一个fragment作为根容器
class NavigationActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_navigation)
}
override fun onSupportNavigateUp() =
findNavController(this, R.id.my_nav_host_fragment).navigateUp()
}
一个简单的Navigation demo就写好了