创建资源文件

 

会在res/

新增如下文件

 

然后还会提示你是否加上对应依赖

    implementation 'androidx.navigation:navigation-fragment-ktx:2.4.2'implementation 'androidx.navigation:navigation-ui-ktx:2.4.2'

我们选上是 就加上了

新建两个Fragement

 其布局代码相同 都为

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:tools="http://schemas.android.com/tools"android:layout_width="match_parent"android:layout_height="match_parent"xmlns:app="http://schemas.android.com/apk/res-auto"tools:context=".fragment.DetailNavigationFragment"><Buttonandroid:id="@+id/button9"android:layout_width="wrap_content"android:layout_height="wrap_content"android:text="Button"app:layout_constraintBottom_toBottomOf="parent"app:layout_constraintEnd_toEndOf="parent"app:layout_constraintStart_toStartOf="parent"app:layout_constraintTop_toTopOf="parent"app:layout_constraintVertical_bias="0.499" /></androidx.constraintlayout.widget.ConstraintLayout>

 

针对刚才添加的

my_nav_graph.xml

进行手动添加视图

 

点击+号后选择我们刚才的fragment

 

选中第一个然后鼠标移动到第二个 选中第二个然后移动到第一个 就会新增两个Action

 

然后我们去到接收fragment的页面的布局当中

 在拖拽过程中你可以发现 他会让你选一个graph文件 

选择我们刚才创建好的文件

添加后修改修改布局

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:app="http://schemas.android.com/apk/res-auto"xmlns:tools="http://schemas.android.com/tools"android:layout_width="match_parent"android:layout_height="match_parent"tools:context=".activity.NavigationActivity"><androidx.fragment.app.FragmentContainerViewandroid:id="@+id/fragmentContainerView"android:name="androidx.navigation.fragment.NavHostFragment"android:layout_width="0dp"android:layout_height="0dp"app:defaultNavHost="true"app:layout_constraintBottom_toBottomOf="parent"app:layout_constraintEnd_toEndOf="parent"app:layout_constraintStart_toStartOf="parent"app:layout_constraintTop_toTopOf="parent"app:navGraph="@navigation/my_nav_graph" />
</androidx.constraintlayout.widget.ConstraintLayout>

对应的页面代码

package com.anguomob.jecpack.activityimport android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import androidx.navigation.fragment.NavHostFragment
import androidx.navigation.ui.NavigationUI
import com.anguomob.jecpack.R
import com.anguomob.jecpack.databinding.ActivityNavigationBindingclass NavigationActivity : AppCompatActivity() {private lateinit var binding: ActivityNavigationBindingoverride fun onCreate(savedInstanceState: Bundle?) {super.onCreate(savedInstanceState)binding = ActivityNavigationBinding.inflate(layoutInflater)setContentView(binding.root)//fragment的切换 通过NavController进行管理val navHostFragment = supportFragmentManager.findFragmentById(R.id.fragmentContainerView) as NavHostFragmentval navController = navHostFragment.navControllerNavigationUI.setupActionBarWithNavController(this, navController = navController)}//支持返回键override fun onSupportNavigateUp(): Boolean {val navHostFragment = supportFragmentManager.findFragmentById(R.id.fragmentContainerView) as NavHostFragmentval navController = navHostFragment.navControllerreturn navController.navigateUp()}
}

对应

HomeNavigationFragment 代码

package com.anguomob.jecpack.fragmentimport android.os.Bundle
import androidx.fragment.app.Fragment
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.Button
import androidx.navigation.Navigation
import com.anguomob.jecpack.R
import com.anguomob.jecpack.databinding.ActivityNavigationBinding
import com.anguomob.jecpack.databinding.FragmentHomeNavigationBindingclass HomeNavigationFragment : Fragment() {private lateinit var binding: FragmentHomeNavigationBindingoverride fun onCreateView(inflater: LayoutInflater, container: ViewGroup?,savedInstanceState: Bundle?): View? {binding = FragmentHomeNavigationBinding.inflate(inflater)
//        inflater.inflate(R.layout.fragment_home_navigation, container, false)return binding.root}override fun onActivityCreated(savedInstanceState: Bundle?) {super.onActivityCreated(savedInstanceState)binding.btHome.setOnClickListener {val findNavController = Navigation.findNavController(it)findNavController.navigate(R.id.action_homeNavigationFragment_to_detailNavigationFragment)}}
}

布局

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:app="http://schemas.android.com/apk/res-auto"xmlns:tools="http://schemas.android.com/tools"android:layout_width="match_parent"android:layout_height="match_parent"tools:context=".fragment.HomeNavigationFragment"><Buttonandroid:id="@+id/btHome"android:layout_width="wrap_content"android:layout_height="wrap_content"android:text="我是主页，我要去详情页"app:layout_constraintBottom_toBottomOf="parent"app:layout_constraintEnd_toEndOf="parent"app:layout_constraintStart_toStartOf="parent"app:layout_constraintTop_toTopOf="parent"app:layout_constraintVertical_bias="0.499" />
</androidx.constraintlayout.widget.ConstraintLayout>

detail fragment代码

package com.anguomob.jecpack.fragmentimport android.os.Bundle
import androidx.fragment.app.Fragment
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import androidx.navigation.Navigation
import com.anguomob.jecpack.R
import com.anguomob.jecpack.databinding.FragmentDetailNavigationBinding
import com.anguomob.jecpack.databinding.FragmentHomeNavigationBinding// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private const val ARG_PARAM1 = "param1"
private const val ARG_PARAM2 = "param2"/*** A simple [Fragment] subclass.* Use the [DetailNavigationFragment.newInstance] factory method to* create an instance of this fragment.*/
class DetailNavigationFragment : Fragment() {private lateinit var binding: FragmentDetailNavigationBindingoverride fun onCreateView(inflater: LayoutInflater, container: ViewGroup?,savedInstanceState: Bundle?): View? {binding = FragmentDetailNavigationBinding.inflate(inflater)
//        inflater.inflate(R.layout.fragment_home_navigation, container, false)return binding.root}override fun onActivityCreated(savedInstanceState: Bundle?) {super.onActivityCreated(savedInstanceState)binding.btDetail.setOnClickListener {val findNavController = Navigation.findNavController(it)findNavController.navigate(R.id.action_detailNavigationFragment_to_homeNavigationFragment)}}
}

布局

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:tools="http://schemas.android.com/tools"android:layout_width="match_parent"android:layout_height="match_parent"xmlns:app="http://schemas.android.com/apk/res-auto"tools:context=".fragment.DetailNavigationFragment"><Buttonandroid:id="@+id/btDetail"android:layout_width="wrap_content"android:layout_height="wrap_content"android:text="我是详情页，我要去主页"app:layout_constraintBottom_toBottomOf="parent"app:layout_constraintEnd_toEndOf="parent"app:layout_constraintStart_toStartOf="parent"app:layout_constraintTop_toTopOf="parent"app:layout_constraintVertical_bias="0.499" /></androidx.constraintlayout.widget.ConstraintLayout>

然后就是可以运行看下效果