Navigation 组件(一) Fragment 跳转

1. App Module 库 build.gradle 文件中添加依赖库或者添加xml文件刷新自动添加库

dependencies {
    implementation 'androidx.navigation:navigation-fragment:2.5.1'
    implementation 'androidx.navigation:navigation-ui:2.5.1'
}

2. 创建 HomeFragment,右击包名，New -> Fragment -> Fragment(Blank),填入 Fragment 和 xml 文件名称

  2.1 HomeFragment.java

public class HomeFragment extends Fragment {
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        return inflater.inflate(R.layout.fragment_home, container, false);
    }
 
    @Override
    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        view.findViewById(R.id.button).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                NavController controller = Navigation.findNavController(view);
                controller.navigate(R.id.action_homeFragment_to_detailFragment);
            }
        });
    }
}

  2.2 fragment_home.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout 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=".HomeFragment">
 
    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">
 
        <androidx.constraintlayout.widget.Guideline
            android:id="@+id/guideline2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            app:layout_constraintGuide_percent="0.5" />
 
        <TextView
            android:id="@+id/textView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Home"
            android:textSize="24sp"
            app:layout_constraintBottom_toTopOf="@+id/guideline2"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintVertical_bias="0.8" />
 
        <Button
            android:id="@+id/button"
            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="@+id/guideline2"
            app:layout_constraintVertical_bias="0.2" />
    </androidx.constraintlayout.widget.ConstraintLayout>
</FrameLayout>

3. 创建 DetailFragment

  3.1 DetailFragment.java

public class DetailFragment extends Fragment {
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        return inflater.inflate(R.layout.fragment_detail, container, false);
    }
 
    @Override
    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        view.findViewById(R.id.button2).setOnClickListener(Navigation.createNavigateOnClickListener(R.id.action_detailFragment_to_homeFragment));
    }
}

  3.2 fragment_detail.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout 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=".DetailFragment">
 
    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">
 
        <androidx.constraintlayout.widget.Guideline
            android:id="@+id/guideline3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            app:layout_constraintGuide_percent="0.5" />
 
        <TextView
            android:id="@+id/textView2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Detail"
            android:textSize="24sp"
            app:layout_constraintBottom_toTopOf="@+id/guideline3"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintVertical_bias="0.8" />
 
        <Button
            android:id="@+id/button2"
            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_constraintHorizontal_bias="0.5"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="@+id/guideline3"
            app:layout_constraintVertical_bias="0.2" />
    </androidx.constraintlayout.widget.ConstraintLayout>
</FrameLayout>

4. 创建 Navigation, 右击 res 文件，选择 New -> Android Resource File, 文件名为 my_navigation.xml ,资源文件类型为 Navigation, 添加 fragment xml 文件。

  4.1 my_navigation.xml 文件

<?xml version="1.0" encoding="utf-8"?>
<navigation 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:id="@+id/my_navigation"
    app:startDestination="@id/homeFragment">
    <fragment
        android:id="@+id/homeFragment"
        android:name="com.example.navigationdemo.HomeFragment"
        android:label="Home"
        tools:layout="@layout/fragment_home">
        <action
            android:id="@+id/action_homeFragment_to_detailFragment"
            app:destination="@id/detailFragment"
            app:enterAnim="@anim/nav_default_enter_anim"
            app:exitAnim="@anim/nav_default_exit_anim" />
    </fragment>
    <fragment
        android:id="@+id/detailFragment"
        android:name="com.example.navigationdemo.DetailFragment"
        android:label="Detail"
        tools:layout="@layout/fragment_detail">
        <action
            android:id="@+id/action_detailFragment_to_homeFragment"
            app:destination="@id/homeFragment"
            app:enterAnim="@anim/nav_default_enter_anim"
            app:exitAnim="@anim/nav_default_exit_anim" />
    </fragment>
</navigation>

5. Activity调用

  5.1 activity_main.xml 文件，画板中，选择 Containers -> NavHostFragment -> my_navigation

<?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=".MainActivity">
 
    <androidx.fragment.app.FragmentContainerView
        android:id="@+id/fragmentContainerView"
        android:name="androidx.navigation.fragment.NavHostFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:defaultNavHost="true"
        app:navGraph="@navigation/my_navigation" />
</androidx.constraintlayout.widget.ConstraintLayout>

  5.2 MainActivity.java 中调用

public class MainActivity extends AppCompatActivity {
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        NavHostFragment navHostFragment = (NavHostFragment) getSupportFragmentManager().findFragmentById(R.id.fragmentContainerView);
        NavController controller = navHostFragment.getNavController();
        NavigationUI.setupActionBarWithNavController(this, controller);
    }
 
    @Override
    public boolean onSupportNavigateUp() {
        NavHostFragment navHostFragment = (NavHostFragment) getSupportFragmentManager().findFragmentById(R.id.fragmentContainerView);
        NavController controller = navHostFragment.getNavController();
        return controller.navigateUp();
    }
}

6. 效果图