底部导航动态效果

1. 项目添加资源文件和引用库

  1.1 build.gradle 添加引用库

dependencies {
    def nav_version = "2.5.2"
    // Kotlin
    implementation "androidx.navigation:navigation-fragment-ktx:$nav_version"
    implementation "androidx.navigation:navigation-ui-ktx:$nav_version"
}

  1.2 string.xml 文件添加文字

    <string name="message_icon_title">消息</string>
    <string name="contact_icon_title">通讯录</string>
    <string name="explore_icon_title">发现</string>
    <string name="account_icon_title">我</string>

  1.3 创建系统矢量图标，例如 message 图标1 ic_baseline_message_fill.xml

<vector xmlns:android="http://schemas.android.com/apk/res/android"
    android:width="24dp"
    android:height="24dp"
    android:autoMirrored="true"
    android:tint="#000000"
    android:viewportWidth="24"
    android:viewportHeight="24">
    <path
        android:fillColor="@android:color/white"
        android:pathData="M20,2L4,2c-1.1,0 -1.99,0.9 -1.99,2L2,22l4,-4h14c1.1,0 2,-0.9 2,-2L22,4c0,-1.1 -0.9,-2 -2,-2zM18,14L6,14v-2h12v2zM18,11L6,11L6,9h12v2zM18,8L6,8L6,6h12v2z" />
</vector>

  1.4 message 图标2 ic_baseline_message_stroke.xml

<vector xmlns:android="http://schemas.android.com/apk/res/android"
    android:width="24dp"
    android:height="24dp"
    android:autoMirrored="true"
    android:tint="#000000"
    android:viewportWidth="24"
    android:viewportHeight="24">
    <path
        android:strokeColor="@android:color/white"
        android:strokeWidth="1"
        android:pathData="M20,2L4,2c-1.1,0 -1.99,0.9 -1.99,2L2,22l4,-4h14c1.1,0 2,-0.9 2,-2L22,4c0,-1.1 -0.9,-2 -2,-2zM18,14L6,14v-2h12v2zM18,11L6,11L6,9h12v2zM18,8L6,8L6,6h12v2z" />
</vector>

  1.5 contact，explore，account 图标创建方法一致，从系统自带矢量图标中查找添加并修改

2. 创建 Fragment 页面

  依次创建 MessageFragment，ContactFragment，ExploreFragment，AccountFragment 四个空白页

  2.1 例如 MessageFragment 页面，MessageFragment.kt，其他页面创建方法一致

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

  2.2 布局文件 fragment_message.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout 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"
    tools:context=".MessageFragment">
    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center"
        android:text="@string/message_icon_title" />
</FrameLayout>

3. Fragment 导航布局 navigation.xml

<?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/navigation"
    app:startDestination="@id/messageFragment">
    <fragment
        android:id="@+id/messageFragment"
        android:name="com.example.bottomview.MessageFragment"
        android:label="@string/message_icon_title"
        tools:layout="@layout/fragment_message" />
    <fragment
        android:id="@+id/contactFragment"
        android:name="com.example.bottomview.ContactFragment"
        android:label="@string/contact_icon_title" />
    <fragment
        android:id="@+id/exploreFragment"
        android:name="com.example.bottomview.ExploreFragment"
        android:label="@string/explore_icon_title"
        tools:layout="@layout/fragment_explore" />
    <fragment
        android:id="@+id/accountFragment"
        android:name="com.example.bottomview.AccountFragment"
        android:label="@string/account_icon_title"
        tools:layout="@layout/fragment_account" />
</navigation>

4. Main 主页内容

  4.1 布局文件 activity_main.xml

<?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="0dp"
        app:defaultNavHost="true"
        app:layout_constraintBottom_toTopOf="@+id/linearLayout"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:navGraph="@navigation/navigation" />

    <LinearLayout
        android:id="@+id/linearLayout"
        android:layout_width="0dp"
        android:layout_height="56dp"
        android:background="#ebebed"
        android:gravity="center_vertical"
        android:orientation="horizontal"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent">

        <include
            android:id="@+id/includeMessage"
            layout="@layout/message_icon_layout"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1" />

        <include
            android:id="@+id/includeContact"
            layout="@layout/contact_icon_layout"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1" />

        <include
            android:id="@+id/includeExplore"
            layout="@layout/explore_icon_layout"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1" />

        <include
            android:id="@+id/includeAccount"
            layout="@layout/account_icon_layout"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1" />
    </LinearLayout>
</androidx.constraintlayout.widget.ConstraintLayout>

  4.2 布局文件 message_icon_layout.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.motion.widget.MotionLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/messageMotionLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="?attr/selectableItemBackgroundBorderless"
    app:layoutDescription="@xml/icon_layout_scene">

    <androidx.constraintlayout.utils.widget.ImageFilterView
        android:id="@+id/imageView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:altSrc="@drawable/ic_baseline_message_fill"
        app:layout_constraintBottom_toTopOf="@+id/textView"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:srcCompat="@drawable/ic_baseline_message_stroke" />

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/message_icon_title"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/imageView" />
</androidx.constraintlayout.motion.widget.MotionLayout>

  4.3 布局文件 contact_icon_layout.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.motion.widget.MotionLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/contactMotionLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="?attr/selectableItemBackgroundBorderless"
    app:layoutDescription="@xml/icon_layout_scene">

    <androidx.constraintlayout.utils.widget.ImageFilterView
        android:id="@+id/imageView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:altSrc="@drawable/ic_baseline_perm_contact_fill"
        app:layout_constraintBottom_toTopOf="@+id/textView"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:srcCompat="@drawable/ic_baseline_perm_contact_stroke" />

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/contact_icon_title"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/imageView" />
</androidx.constraintlayout.motion.widget.MotionLayout>

  4.4 布局文件 explore_icon_layout.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.motion.widget.MotionLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/exploreMotionLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="?attr/selectableItemBackgroundBorderless"
    app:layoutDescription="@xml/icon_layout_scene">

    <androidx.constraintlayout.utils.widget.ImageFilterView
        android:id="@+id/imageView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:altSrc="@drawable/ic_baseline_explore_fill"
        app:layout_constraintBottom_toTopOf="@+id/textView"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:srcCompat="@drawable/ic_baseline_explore_stroke" />

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/explore_icon_title"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/imageView" />
</androidx.constraintlayout.motion.widget.MotionLayout>

  4.5 布局文件 account_icon_layout.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.motion.widget.MotionLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/accountMotionLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="?attr/selectableItemBackgroundBorderless"
    app:layoutDescription="@xml/icon_layout_scene">

    <androidx.constraintlayout.utils.widget.ImageFilterView
        android:id="@+id/imageView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:altSrc="@drawable/ic_baseline_account_circle_fill"
        app:layout_constraintBottom_toTopOf="@+id/textView"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:srcCompat="@drawable/ic_baseline_account_circle_stroke" />

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/account_icon_title"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/imageView" />
</androidx.constraintlayout.motion.widget.MotionLayout>

  4.6 自动生成动画场景文件，共同引用 icon_layout_scene.xml

<?xml version="1.0" encoding="utf-8"?>
<MotionScene xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:motion="http://schemas.android.com/apk/res-auto">

    <Transition
        motion:constraintSetEnd="@+id/end"
        motion:constraintSetStart="@id/start"
        motion:duration="300">
        <KeyFrameSet>
            <KeyCycle
                android:translationX="5dp"
                motion:framePosition="1"
                motion:motionTarget="@+id/imageView"
                motion:waveOffset="0dp"
                motion:wavePeriod="1" />
        </KeyFrameSet>
    </Transition>

    <ConstraintSet android:id="@+id/start">
        <Constraint
            android:id="@+id/imageView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            motion:layout_constraintBottom_toTopOf="@+id/textView"
            motion:layout_constraintEnd_toEndOf="parent"
            motion:layout_constraintHorizontal_bias="0.5"
            motion:layout_constraintStart_toStartOf="parent"
            motion:layout_constraintTop_toTopOf="parent">
            <CustomAttribute
                motion:attributeName="crossfade"
                motion:customFloatValue="0" />
            <CustomAttribute
                motion:attributeName="colorFilter"
                motion:customColorValue="#000000" />
        </Constraint>
        <Constraint
            android:id="@+id/textView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            motion:layout_constraintBottom_toBottomOf="parent"
            motion:layout_constraintEnd_toEndOf="parent"
            motion:layout_constraintHorizontal_bias="0.5"
            motion:layout_constraintStart_toStartOf="parent"
            motion:layout_constraintTop_toBottomOf="@+id/imageView">
            <CustomAttribute
                motion:attributeName="textColor"
                motion:customColorValue="#000000" />
        </Constraint>
    </ConstraintSet>

    <ConstraintSet android:id="@+id/end">
        <Constraint
            android:id="@+id/imageView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            motion:layout_constraintBottom_toTopOf="@+id/textView"
            motion:layout_constraintEnd_toEndOf="parent"
            motion:layout_constraintHorizontal_bias="0.5"
            motion:layout_constraintStart_toStartOf="parent"
            motion:layout_constraintTop_toTopOf="parent">
            <CustomAttribute
                motion:attributeName="crossfade"
                motion:customFloatValue="1" />
            <CustomAttribute
                motion:attributeName="colorFilter"
                motion:customColorValue="@color/purple_500" />
        </Constraint>
        <Constraint
            android:id="@+id/textView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            motion:layout_constraintBottom_toBottomOf="parent"
            motion:layout_constraintEnd_toEndOf="parent"
            motion:layout_constraintHorizontal_bias="0.5"
            motion:layout_constraintStart_toStartOf="parent"
            motion:layout_constraintTop_toBottomOf="@+id/imageView">
            <CustomAttribute
                motion:attributeName="textColor"
                motion:customColorValue="@color/purple_500" />
        </Constraint>
    </ConstraintSet>
</MotionScene>

  4.7 Activity 中调用，MainActivity.kt

class MainActivity : AppCompatActivity() {
    private lateinit var navController: NavController
    private lateinit var binding: ActivityMainBinding

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = ActivityMainBinding.inflate(layoutInflater)
        setContentView(binding.root)
        reInitView()
    }

    //重构简单写法
    private fun reInitView() {
        with(binding) {
            val destinationMap = mapOf(
                R.id.messageFragment to includeMessage.messageMotionLayout,
                R.id.contactFragment to includeContact.contactMotionLayout,
                R.id.exploreFragment to includeExplore.exploreMotionLayout,
                R.id.accountFragment to includeAccount.accountMotionLayout
            )
            navController = fragmentContainerView.getFragment<NavHostFragment>().navController
            setupActionBarWithNavController(navController, AppBarConfiguration(destinationMap.keys))
            destinationMap.forEach { map ->
                map.value.setOnClickListener {
                    navController.navigate(map.key)
                }
            }
            //监听导航栏
            navController.addOnDestinationChangedListener { controller, destination, _ ->
                //将返回站清空，不会按返回键有回弹效果
                controller.popBackStack()
                destinationMap.forEach {
                    it.value.progress = 0f
                }
                destinationMap[destination.id]?.transitionToEnd()
            }
        }
    }

    //常用写法
    private fun initView() {
        with(binding) {
            navController = fragmentContainerView.getFragment<NavHostFragment>().navController
            setupActionBarWithNavController(
                navController, AppBarConfiguration(
                    setOf(
                        R.id.messageFragment,
                        R.id.contactFragment,
                        R.id.exploreFragment,
                        R.id.accountFragment
                    )
                )
            )
            includeMessage.messageMotionLayout.setOnClickListener {
                navController.navigate(R.id.messageFragment)
            }
            includeContact.contactMotionLayout.setOnClickListener {
                navController.navigate(R.id.contactFragment)
            }
            includeExplore.exploreMotionLayout.setOnClickListener {
                navController.navigate(R.id.exploreFragment)
            }
            includeAccount.accountMotionLayout.setOnClickListener {
                navController.navigate(R.id.accountFragment)
            }

            //监听导航栏
            navController.addOnDestinationChangedListener { controller, destination, _ ->
                //将返回站清空，不会按返回键有回弹效果
                controller.popBackStack()
                includeMessage.messageMotionLayout.progress = 0f
                includeContact.contactMotionLayout.progress = 0f
                includeExplore.exploreMotionLayout.progress = 0f
                includeAccount.accountMotionLayout.progress = 0f
                when (destination.id) {
                    R.id.messageFragment -> includeMessage.messageMotionLayout.transitionToEnd()
                    R.id.contactFragment -> includeContact.contactMotionLayout.transitionToEnd()
                    R.id.exploreFragment -> includeExplore.exploreMotionLayout.transitionToEnd()
                    else -> includeAccount.accountMotionLayout.transitionToEnd()
                }
            }
        }
    }
}

5. 效果图