Android jetpack（Navigation篇）

2021-05-26 本文已影响0人坑逼的严

看到网上很对人吐槽navigation如何多余，以及在xml里面编写大量代码，不利于阅读等，其实对于习惯用代码处理逻辑的我来说，确实觉得不怎么方便，但是我总觉得谷歌有着自己的宏伟目标，那就是可视化编程，看着后面推出来的ConstraintLayout以及navigation，DataBinding等，都在可视化编程上给了更多的便利。总之，存在即合理。用不到也要学习学习。所以做个笔记。

使用

使用的时候可以遵循这个顺序，建立需要的Fragment-》建立NavigationGraph并建立跳转链接-》activity中建立NaviHost-》NavController的调用
所以我们先建立两个Fragment我这里就用HomeFragment、DetailFragment示意，在这两个Fragment中都有一个按钮，HomeFragment的按钮点击跳转到DetailFragment，DetailFragment的按钮点击回到HomeFragment。当然我们暂时先把button写出来即可，点击跳转等NavController绑定后填写。
他们的布局如下：
fragment_home.xml

<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=".navigation.HomeFragment">


    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="66dp"
        android:text="跳转"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

fragment_detail.xml

<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=".navigation.DetailFragment">

    <Button
        android:id="@+id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="返回"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

第二步创建navigationGraph。在res下新建navigation文件夹，并建立一个要用的graph文件

image.png

当点击新建时会提示需要引入资源，点击ok即可。

image.png
找到刚刚新建的graph文件，选择design模式。

image.png

点击添加Fragment

image.png
使用箭头配置跳转关系

image.png
然后他就能自动帮我们编写代码，最后生成的xml如下：
my_navi_graph.xml

<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_navi_graph"
    app:startDestination="@id/homeFragment">

    <fragment
        android:id="@+id/homeFragment"
        android:name="com.example.myapplication.navigation.HomeFragment"
        android:label="fragment_home"
        tools:layout="@layout/fragment_home" >
        <action
            android:id="@+id/action_homeFragment_to_detailFragment"
            app:destination="@id/detailFragment" />
    </fragment>
    <fragment
        android:id="@+id/detailFragment"
        android:name="com.example.myapplication.navigation.DetailFragment"
        android:label="fragment_detail"
        tools:layout="@layout/fragment_detail" >
        <action
            android:id="@+id/action_detailFragment_to_homeFragment"
            app:destination="@id/homeFragment" />
    </fragment>
</navigation>

然后activity中建立Navigation容器。
找到activity布局，还是用design模式，搜索框内找到NavHostFragment，拖拽一个NavHostFragment到下面的约束布局中，并撑满全屏。

image.png

然后会让你选择一个graph，我们就选择刚刚新建的即可

image.png
最终activity的布局代码如下：
activity_navigation.xml

<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=".navigation.NavigationActivity">

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

最后我们在activity中绑定上我们的控制器，

public class NavigationActivity extends AppCompatActivity {

    private NavController mNavController;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_navigation);
        mNavController = Navigation.findNavController(this, R.id.fragment);
        NavigationUI.setupActionBarWithNavController(this,mNavController);
    }
}

然后就可以设置fragment的点击事件了。
HomeFragment

public class HomeFragment extends Fragment {

    public static HomeFragment newInstance() {
        HomeFragment fragment = new HomeFragment();
        Bundle args = new Bundle();
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        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 v) {
                NavController navController = Navigation.findNavController(v);
                navController.navigate(R.id.action_homeFragment_to_detailFragment);
            }
        });
    }
}

DetailFragment

public class DetailFragment extends Fragment {

    public static DetailFragment newInstance() {
        DetailFragment fragment = new DetailFragment();
        Bundle args = new Bundle();
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        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(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                NavController navController = Navigation.findNavController(v);
                navController.navigate(R.id.action_detailFragment_to_homeFragment);
            }
        });
    }
}

这样，我们的跳转就算完成了，但是进入DetailFragment 后 actionbar上的返回按钮不能返回到HomeFragment了，原因是我们应该告诉actionbar原来的机制，我们的逻辑由navigation控制了，你们不用操心了，只要在activity中复写onSupportNavigateUp即可

public class NavigationActivity extends AppCompatActivity {

    private NavController mNavController;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_navigation);
        mNavController = Navigation.findNavController(this, R.id.fragment);
        NavigationUI.setupActionBarWithNavController(this,mNavController);
    }

    @Override
    public boolean onSupportNavigateUp() {
        return mNavController.navigateUp() || super.onSupportNavigateUp();
    }
}

跳转动画

选择graph文件，使用design模式，点击你想要添加动画的跳转箭头那根线，右边的Animations就有我们需要的进场动画当然支持自定义也支持默认动画。

image.png

设置完成后，xml代码就会自定生成

image.png

传值

传统的fragment传值是通过Bundle传值，他存在明显的缺点，比如A传值给B，B在接收的时候必须知道A传过来的KEY和值得数据类型，不然就会报错。而Navigation对此也进行了修改。
Navigation传值需要引入插件，在整个工程的gradle中引入 classpath 'androidx.navigation:navigation-safe-args-gradle-plugin:2.3.0-alpha06' 如图：

image.png

然后在需要的model中的gradle引入apply plugin: 'androidx.navigation.safeargs'

image.png

然后我们找到graph文件，在需要的地方加上传值

image.png

<argument android:name="user_name"
            app:argType="string"
            android:defaultValue=""/>
        <argument android:name="age"
            app:argType="integer"
            android:defaultValue="0"/>

然后build一下工程，插件会生成一些代码。
我们是添加在Home跳Detail的跳转中，所以我们在Home的按钮点击实践中传入值。

image.png

public class HomeFragment extends Fragment {

    public static HomeFragment newInstance() {
        HomeFragment fragment = new HomeFragment();
        Bundle args = new Bundle();
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        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 v) {
                Bundle bundle = new HomeFragmentArgs.Builder()
                        .setUserName("yanjin")
                        .setAge(25).build().toBundle();
                NavController navController = Navigation.findNavController(v);
                navController.navigate(R.id.action_homeFragment_to_detailFragment,bundle);
            }
        });
    }
}

在DetailFragment取值。

public class DetailFragment extends Fragment {

    public static DetailFragment newInstance() {
        DetailFragment fragment = new DetailFragment();
        Bundle args = new Bundle();
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if(getArguments() != null){
            HomeFragmentArgs fragmentArgs = HomeFragmentArgs.fromBundle(getArguments());
            String userName = fragmentArgs.getUserName();
            int age = fragmentArgs.getAge();
            Log.d("yanjin","userName = "+userName +" age ="+age);
        }
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        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(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                NavController navController = Navigation.findNavController(v);
                navController.navigate(R.id.action_detailFragment_to_homeFragment);
            }
        });
    }
}

NavigationUI

NavigationUI是为了方便管理actionBar引入的。比如我们在Home的actionBar上面加入一个menu，点击跳转到Detail中，涉及到actionBar就能用到NavigationUI。
新建一个menu

image.png

menu_settings.xml

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:id="@+id/detailFragment"
        android:icon="@mipmap/ic_launcher"
        android:title="跳转到detail"/>
</menu>

记住这里的android:id="@+id/detailFragment"一定和graph里面的id一致，跳哪个页面填哪个。
然后activity中设置appbar

public class NavigationActivity extends AppCompatActivity {

    private NavController mNavController;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_navigation);
        mNavController = Navigation.findNavController(this, R.id.fragment);
        AppBarConfiguration appBarConfiguration = new AppBarConfiguration.Builder(mNavController.getGraph()).build();
        NavigationUI.setupActionBarWithNavController(this,mNavController,appBarConfiguration);
    }

    @Override
    public boolean onSupportNavigateUp() {
        return mNavController.navigateUp() || super.onSupportNavigateUp();
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        super.onCreateOptionsMenu(menu);
        getMenuInflater().inflate(R.menu.menu_settings,menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(@NonNull MenuItem item) {
        return NavigationUI.onNavDestinationSelected(item,mNavController) || super.onOptionsItemSelected(item);
    }
}

深层链接之PendingIntent

在开发中，我们可能需要点击通知跳转到一个activity下的第N个fragment，所以就用到PendingIntent，Navigation刚好支持在activity中的多个fragment中显示第N个，所以，我们来举个例子。
我们在HomeFragment中点击一个按钮出现通知，点击通知跳转到DetailFragment。
首先home的布局添加一个按钮

<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=".navigation.HomeFragment">


    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="66dp"
        android:text="跳转"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/button3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="弹出通知"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

然后点击按钮后提示弹窗并且按钮notify绑定pendingIntent

public class HomeFragment extends Fragment {

    private int notificationID;

    public static HomeFragment newInstance() {
        HomeFragment fragment = new HomeFragment();
        Bundle args = new Bundle();
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        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 v) {
                Bundle bundle = new HomeFragmentArgs.Builder()
                        .setUserName("yanjin")
                        .setAge(25).build().toBundle();
                NavController navController = Navigation.findNavController(v);
                navController.navigate(R.id.action_homeFragment_to_detailFragment,bundle);
            }
        });
        view.findViewById(R.id.button3).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                customNotify();
            }
        });
    }

    private void customNotify() {
        //26以上需要渠道
        if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.O){
            NotificationChannel channel = new NotificationChannel(getActivity().getPackageName(),"MyChannel", NotificationManager.IMPORTANCE_DEFAULT);
            channel.setDescription("My NotificationChannel");
            NotificationManager notificationManager = getActivity().getSystemService(NotificationManager.class);
            notificationManager.createNotificationChannel(channel);
        }
        Notification notification = new NotificationCompat.Builder(getActivity(), getActivity().getPackageName())
                .setSmallIcon(R.drawable.ic_launcher_foreground)
                .setContentTitle("Deep Link")
                .setContentText("点击跳转")
                .setPriority(NotificationCompat.PRIORITY_DEFAULT)
                .setContentIntent(getPendingIntent()).build();
        NotificationManagerCompat notificationManagerCompat = NotificationManagerCompat.from(getActivity());
        notificationManagerCompat.notify(notificationID++,notification);
    }

    private PendingIntent getPendingIntent() {
        return Navigation.findNavController(getActivity(),R.id.button)
                .createDeepLink()
                .setGraph(R.navigation.my_navi_graph)
                .setDestination(R.id.detailFragment)
                .createPendingIntent();
    }
}

Android jetpack（Navigation篇）

使用

跳转动画

传值

NavigationUI

深层链接之PendingIntent

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