Architecture -- Navigation

原文链接

1). 依赖

dependencies {
    def nav_version = "1.0.0-alpha07"

    implementation "android.arch.navigation:navigation-fragment:$nav_version" // use -ktx for Kotlin
    implementation "android.arch.navigation:navigation-ui:$nav_version" // use -ktx for Kotlin

    // optional - Test helpers
    // this library depends on the Kotlin standard library
    androidTestImplementation "android.arch.navigation:navigation-testing:$nav_version"
}

• Safe args

buildscript {
    // google仓库
    maven {
      url 'https://maven.aliyun.com/repository/google'
    }
    dependencies {
        classpath "android.arch.navigation:navigation-safe-args-gradle-plugin:1.0.0-alpha07"
    }
}

在模块的build.gradle文件中添加

apply plugin: "androidx.navigation.safeargs"

2). 开启编辑器

File -> Settings -> Experimental -> Editor -> 勾选Enable Navigatioon Editor.

图1.jpg

3). 创建导航图

I. 创建资源文件
在res文件夹上右键，选择Android Resource File

图2.png

II. 创建nav_graph.xml文件
输入文件名(File Name) 为nav_graph，并选择资源类型(Resource type) 为Navigation，此处如果没有勾选上一步的编辑器，则资源类型中没有Navigation选项.

图3.png

III. 目录
点击OK之后，res目录下会出现navigation文件夹，navigation文件夹下会出现nav_graph.xml文件

图4.png

IV. nav_graph.xml文件内容如下

<?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"
            android:id="@+id/nav_graph">

</navigation>

V. 编辑器样式

图5.png

4). 创建Fragment

I. 点击图5中的红色部位按钮(New Destination)创建Fragment

图6.png

II. 选择Create blank destination

图7.png

III. 连续创建两个，重复上面操作即可
IV. 连接

图8.png

V. 设置后的nav_graph.xml代码

<?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/nav_graph"
            app:startDestination="@id/blankFragment">

  <fragment
      android:id="@+id/blankFragment"
      android:name="com.mazaiting.jetpack.BlankFragment"
      android:label="fragment_blank"
      tools:layout="@layout/fragment_blank">
    <action
        android:id="@+id/action_blankFragment_to_blankFragment2"
        app:destination="@id/blankFragment2"/>
  </fragment>
  <fragment
      android:id="@+id/blankFragment2"
      android:name="com.mazaiting.jetpack.BlankFragment2"
      android:label="fragment_blank_fragment2"
      tools:layout="@layout/fragment_blank_fragment2"/>
</navigation>

VI. 修改Fragment位置
此时Framgent位置在包名下，在指定位置下创建fragment文件夹，将新生成的fragment文件移动即可。
VII. 新nav_graph.xml文件代码

<?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/nav_graph"
            app:startDestination="@id/blankFragment">

  <fragment
      android:id="@+id/blankFragment"
      android:name="com.mazaiting.jetpack.architecture.navigation.fragment.BlankFragment"
      android:label="fragment_blank"
      tools:layout="@layout/fragment_blank">
    <action
        android:id="@+id/action_blankFragment_to_blankFragment2"
        app:destination="@id/blankFragment2"/>
  </fragment>
  <fragment
      android:id="@+id/blankFragment2"
      android:name="com.mazaiting.jetpack.architecture.navigation.fragment.BlankFragment2"
      android:label="fragment_blank_fragment2"
      tools:layout="@layout/fragment_blank_fragment2"/>
</navigation>

5). 在Activity中添加Fragment

在activity_navigation.xml文件中添加fragment

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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="com.mazaiting.jetpack.architecture.navigation.NavigationActivity">
    <fragment
      android:name="androidx.navigation.fragment.NavHostFragment"
      android:id="@+id/nav_host_fragment"
      android:layout_width="0dp"
      android:layout_height="0dp"
      app:layout_constraintBottom_toBottomOf="parent"
      app:layout_constraintLeft_toLeftOf="parent"
      app:layout_constraintRight_toRightOf="parent"
      app:layout_constraintTop_toTopOf="parent"
      app:defaultNavHost="true"
      app:navGraph="@navigation/nav_graph" />

</android.support.constraint.ConstraintLayout>

II. 在Activity中重写onNavigateUp()方法

  override fun onNavigateUp(): Boolean = findNavController(this, R.id.nav_host_fragment).navigateUp()

III. 初始化

    /**
     * 如果布局文件的fragment中没有这两行，则需要设置如下内容
     * app:defaultNavHost="true"
     * app:navGraph="@navigation/nav_graph"
     */
    val finalHost = NavHostFragment.create(R.navigation.nav_graph)
    supportFragmentManager.beginTransaction()
            .replace(R.id.nav_host_fragment, finalHost)
            .setPrimaryNavigationFragment(finalHost)
            .commit()

6). 添加按钮

在blankFragment和blankFragment2中分别添加按钮

7). 点击跳转

I. BlankFragment中

    val btnShow: Button = view.findViewById(R.id.btn_show_fragment)
    btnShow.setOnClickListener { btnView ->
      // 跳转下一个页面
      Navigation.findNavController(btnView).navigate(R.id.action_blankFragment_to_blankFragment2)
    }

II. BlankFragment2中

    val btnShow: Button = view.findViewById(R.id.btn_show_fragment2)
    btnShow.setOnClickListener { btnView ->
      // 返回上一页
      Navigation.findNavController(btnView).navigateUp()
    }

III. 效果图

test.gif

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