Android jetpack組件之Navigation使用（基於androidx 基於kotlin）

 

最近有點空餘時間，來學點新東西，就開始學習之前一直想學的Jetpack組件

所以先從Navigation開始，廢話不多說直接開始：

一.先添加相關依賴

    // Java
    implementation "androidx.navigation:navigation-fragment:$nav_version"
    implementation "androidx.navigation:navigation-ui:$nav_version"

    // Kotlin
    implementation "androidx.navigation:navigation-fragment-ktx:$nav_version"
    implementation "androidx.navigation:navigation-ui-ktx:$nav_version"

 

二.在res目錄下新建navigation文件夾，並創建一個navigation類型的xml文件

內容如下：

<?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"
            app:startDestination="@id/page1Fragment">
    <fragment
            android:id="@+id/page1Fragment"
            android:name="com.ypf.myjetpack.MainPage1Fragment"
            android:label="fragment_page1"
            tools:layout="@layout/fragment_main_page1">
        <action
                android:id="@+id/action_page2"
                app:destination="@id/page2Fragment"/>
    </fragment>

    <fragment
            android:id="@+id/page2Fragment"
            android:name="com.ypf.myjetpack.MainPage2Fragment"
            android:label="fragment_page2"
            tools:layout="@layout/fragment_main_page2">
        <action
                android:id="@+id/action_page1"
                app:popUpTo="@id/page1Fragment"/>
        <action
                android:id="@+id/action_page3"
                app:destination="@id/nav_graph_page3"/>
    </fragment>

    <navigation
            android:id="@+id/nav_graph_page3"
            app:startDestination="@id/page3Fragment">
        <fragment
                android:id="@+id/page3Fragment"
                android:name="com.ypf.myjetpack.MainPage3Fragment"
                android:label="fragment_page3"
                tools:layout="@layout/fragment_main_page3"/>
    </navigation>


</navigation>

三.新建三個Fragment並設置跳轉事件

class MainPage1Fragment : Fragment() {


    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?
    ): View {
        return inflater.inflate(R.layout.fragment_main_page1, container, false)
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        btn_one.setOnClickListener{
            Navigation.findNavController(it).navigate(R.id.action_page2)
        }
    }

}

class MainPage2Fragment : Fragment() {

    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        return inflater.inflate(R.layout.fragment_main_page2, container, false)
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        btn_two.setOnClickListener {
            //點擊返回page1
            Navigation.findNavController(it).navigateUp()
        }
        btn_two_2.setOnClickListener {
            Navigation.findNavController(it).navigate(R.id.action_page3)
        }
    }
}


class MainPage3Fragment : Fragment() {

    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?,
                              savedInstanceState: Bundle?): View? {
        return inflater.inflate(R.layout.fragment_main_page3, container, false)
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        btn_three.setOnClickListener {
            Navigation.findNavController(it).navigateUp()
        }

    }
}

四.Mainactivity相關配置

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

    }

    override fun onSupportNavigateUp() =
        findNavController(R.id.my_nav_host_fragment).navigateUp()


}

對應的xml：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
        xmlns:app="http://schemas.android.com/apk/res-auto"
        xmlns:tools="http://schemas.android.com/tools" xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/container"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".MainActivity">

    <fragment
            android:id="@+id/my_nav_host_fragment"
            android:name="androidx.navigation.fragment.NavHostFragment"//設置navigation容器
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            app:defaultNavHost="true"//設置是否攔截返回鍵
            app:navGraph="@navigation/nav_graph_main"/>//加載定義的nav_graph_main.xml文件

</LinearLayout>

最終大功告成

效果圖如下：

              圖一                                                                  圖二                                                          圖三

跳轉邏輯如下：

點擊圖一的按鈕切換到Page2，點擊圖二按鈕分別跳轉到page3和上一個頁面

相關源碼：https://download.csdn.net/download/u013075460/11847256