Android Jetpack -- navigation

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

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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

 

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