Question

我正在尝试使用带有导航图和导航控制器的导航组件来实现简单的导航。我的MainActivity带有带汉堡包图标和应用程序标题的操作栏，一个抽屉式导航和内容区域。

内容区域是我显示不同片段的地方。

内容区域首先加载了我的homescreenFragment，其中包含4个按钮（新闻，事件，时间表，配置文件）-每个按钮都将片段加载到MainActivity的“内容”区域中。它工作正常，唯一的问题如下：当我按下新闻按钮并从我的主屏幕导航到我的 NewsFragment 时，它会加载片段OK，并将操作栏标题更改为News。 汉堡包图标更改为“向上按钮”图标，但是当我按它时，应用程序将打开导航抽屉，就像我按汉堡包图标一样，而不是将我导航回到主屏幕。

>

如何使Up（向上）按钮向上移动，而不显示左侧导航抽屉？

这是我的MainActivity.java：

import android.os.Bundle;
import android.support.design.widget.NavigationView;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;

import androidx.navigation.NavController;
import androidx.navigation.Navigation;
import androidx.navigation.ui.NavigationUI;

public class MainActivity extends AppCompatActivity  {

    Toolbar m_toolbar;
    DrawerLayout m_drawer;
    ActionBarDrawerToggle m_toggle;
    NavigationView m_navigationView;
    NavController m_navController;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        m_toolbar = findViewById(R.id.toolbar);
        setSupportActionBar(m_toolbar);

        m_drawer = findViewById(R.id.drawer_layout);

        m_navigationView = findViewById(R.id.nav_drawer_view);

        m_navController = Navigation.findNavController(this, R.id.content);

        m_toggle = new ActionBarDrawerToggle(
                this, m_drawer, m_toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
        m_drawer.addDrawerListener(m_toggle);
        //m_toggle.syncState();

        //connect actionbar icon and drawer with nav controller
        NavigationUI.setupWithNavController(m_navigationView, m_navController);
        NavigationUI.setupActionBarWithNavController(this, m_navController);
        NavigationUI.setupActionBarWithNavController(this, m_navController, m_drawer);

    }

    @Override
    public boolean onSupportNavigateUp() {
        return Navigation.findNavController(this, R.id.nav_drawer_view).navigateUp() || super.onSupportNavigateUp();
    }

    @Override
    public void onBackPressed() {
        DrawerLayout drawer = findViewById(R.id.drawer_layout);
        if (drawer.isDrawerOpen(GravityCompat.START)) {
            drawer.closeDrawer(GravityCompat.START);
        } else {
            super.onBackPressed();
        }
    }


}

我的activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout 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/drawer_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:openDrawer="start">

    <LinearLayout
        android:orientation="vertical"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".MainActivity">

        <android.support.design.widget.AppBarLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:theme="@style/AppTheme.AppBarOverlay">

            <android.support.v7.widget.Toolbar
                android:id="@+id/toolbar"
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"
                android:background="?attr/colorPrimary"
                app:popupTheme="@style/AppTheme.PopupOverlay" />

        </android.support.design.widget.AppBarLayout>

            <FrameLayout
                android:layout_width="match_parent"
                android:layout_height="match_parent">
                <fragment
                    android:id="@+id/content"
                    android:layout_width="match_parent"
                    android:layout_height="match_parent"
                    app:layout_behavior="@string/appbar_scrolling_view_behavior"
                    android:name="androidx.navigation.fragment.NavHostFragment"
                    app:navGraph="@navigation/nav_graph"
                    app:defaultNavHost="true"/>

            </FrameLayout>

    </LinearLayout>

    <android.support.design.widget.NavigationView
        android:id="@+id/nav_drawer_view"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        android:fitsSystemWindows="true"
        app:headerLayout="@layout/nav_header_main"
        app:menu="@menu/activity_main_drawer" />

</android.support.v4.widget.DrawerLayout>

导航图：

<?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/homeScreenFragment">

    <fragment
        android:id="@+id/homeScreenFragment"
        android:name="com.mysample.meganews.Fragments.HomeScreenFragment"
        android:label="@string/app_name"
        tools:layout="@layout/home_screen_fragment" >
        <action
            android:id="@+id/action_to_news"
            app:destination="@id/newsFragment"
            app:enterAnim="@anim/nav_default_enter_anim"
            app:exitAnim="@anim/nav_default_exit_anim" />
        <action
            android:id="@+id/action_to_events"
            app:destination="@id/eventsFragment"
            app:enterAnim="@anim/nav_default_pop_enter_anim"
            app:exitAnim="@anim/nav_default_pop_exit_anim" />
    </fragment>
    <fragment
        android:id="@+id/newsFragment"
        android:name="com.mysample.meganews.Fragments.NewsFragment"
        android:label="@string/hs_title_news"
        tools:layout="@layout/news_fragment" />
    <fragment
        android:id="@+id/eventsFragment"
        android:name="com.mysample.meganews.Fragments.EventsFragment"
        android:label="events_fragment"
        tools:layout="@layout/events_fragment" />
</navigation>

HomeScreenFragment.java文件：

import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.RelativeLayout;

import androidx.navigation.NavController;
import androidx.navigation.Navigation;


/**
 * A simple {@link Fragment} subclass.
 */
public class HomeScreenFragment extends Fragment {


    public HomeScreenFragment() {
        // Required empty public constructor
    }


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.home_screen_fragment, container, false);
    }

    @Override
    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

        RelativeLayout rl_news = view.findViewById(R.id.ll_news_btn);
        RelativeLayout rl_events = view.findViewById(R.id.ll_events_btn);

        rl_news.setOnClickListener(Navigation.createNavigateOnClickListener(R.id.action_to_news));
        rl_events.setOnClickListener(Navigation.createNavigateOnClickListener(R.id.action_to_events));
    }
}

build.gradle文件：

apply plugin: 'com.android.application'

android {
    compileSdkVersion 28
    defaultConfig {
        applicationId "com.mysample.meganews"
        minSdkVersion 16
        targetSdkVersion 28
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'com.android.support:appcompat-v7:28.0.0'
    implementation 'com.android.support:design:28.0.0'
    implementation 'com.android.support.constraint:constraint-layout:1.1.3'
    implementation 'com.android.support:support-v4:28.0.0'
    implementation 'android.arch.lifecycle:extensions:1.1.1'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:1.0.2'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
    implementation 'android.arch.navigation:navigation-fragment:1.0.0-alpha11'
    implementation 'android.arch.navigation:navigation-ui:1.0.0-alpha11'
}

Answer 1

此问题是由于混合使用不同的API引起的。这是正确的代码：

activity_main.xml：

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">

        <androidx.appcompat.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="@color/colorPrimary"
            android:theme="@style/ThemeOverlay.AppCompat.Dark" />
                <fragment
                    android:id="@+id/content"
                    android:layout_width="match_parent"
                    android:layout_height="match_parent"
                    app:layout_behavior="@string/appbar_scrolling_view_behavior"
                    android:name="androidx.navigation.fragment.NavHostFragment"
                    app:navGraph="@navigation/nav_graph"
                    app:defaultNavHost="true"/>

    </LinearLayout>

    <com.google.android.material.navigation.NavigationView
        android:id="@+id/nav_drawer_view"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        app:headerLayout="@layout/nav_header_main"
        app:menu="@menu/activity_main_drawer" />

</androidx.drawerlayout.widget.DrawerLayout>

MainActivity.java：

import android.os.Bundle;


import com.google.android.material.navigation.NavigationView;

import androidx.core.view.GravityCompat;
import androidx.drawerlayout.widget.DrawerLayout;
import androidx.appcompat.app.ActionBarDrawerToggle;
import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.Toolbar;
import androidx.lifecycle.ViewModelProviders;
import androidx.navigation.NavController;
import androidx.navigation.Navigation;
import androidx.navigation.ui.NavigationUI;

import android.view.MenuItem;
import android.view.ViewParent;

public class MainActivity extends AppCompatActivity
{
    private Toolbar mToolbar;
    private DrawerLayout mDrawer;
    private ActionBarDrawerToggle mToggle;
    private NavigationView mNavigationView;
    private NavController mNavController;

    private MainViewModel mViewModel;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);
        mViewModel = ViewModelProviders.of(this).get(MainViewModel.class);

        setupNavigation();
    }

    private void setupNavigation()
    {
        mToolbar = findViewById(R.id.toolbar);
        setSupportActionBar(mToolbar);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);

        mDrawer = findViewById(R.id.drawerLayout);
        mNavigationView = findViewById(R.id.nav_drawer_view);

        mNavigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
            @Override
            public boolean onNavigationItemSelected(MenuItem menuItem) {

//                // we need this line to handle the navigation
//                boolean handled = NavigationUI.onNavDestinationSelected(menuItem, mNavController);
//                if (handled) {
//                    ViewParent parent = mNavigationView.getParent();
//                    if (parent instanceof DrawerLayout) {
//                        ((DrawerLayout) parent).closeDrawer(mNavigationView);
//                    }
//                }

                return true;
            }
        });

        mNavController = Navigation.findNavController(this, R.id.content);
        NavigationUI.setupActionBarWithNavController(this, mNavController, mDrawer);
        // Tie nav graph to items in nav drawer
        NavigationUI.setupWithNavController(mNavigationView, mNavController);
    }


    @Override
    public boolean onSupportNavigateUp() {
        //return Navigation.findNavController(this, R.id.content).navigateUp();
        //return mNavController.navigateUp()  || super.onSupportNavigateUp();
        return NavigationUI.navigateUp(mNavController, mDrawer);
    }

    @Override
    public void onBackPressed() {
        if (mDrawer.isDrawerOpen(GravityCompat.START)) {
            mDrawer.closeDrawer(GravityCompat.START);
        } else {
            super.onBackPressed();
        }
    }

Answer 2

我遇到了同样的问题，并通过以下解决方法进行了修复。

    mNavController.addOnDestinationChangedListener(new NavController.OnDestinationChangedListener() {
        @Override
        public void onDestinationChanged(@NonNull NavController controller,
                                         @NonNull NavDestination destination, @Nullable Bundle arguments) {          
            if (mAppBarConfiguration.getTopLevelDestinations().contains(destination.getId())) {
                mToggle.setDrawerIndicatorEnabled(true);
            } else {
                mToggle.setDrawerIndicatorEnabled(false);
            }
        }
    });

还要确保将点击侦听器设置为ActionBarDrawerToggle，如下所示。

    mToggle.setToolbarNavigationClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            mActivity.onBackPressed();
        }
    });

Answer 3

默认情况下，导航处理此操作，您不必为此显式处理侦听器。在您的活动中覆盖“ onSupportNavigationUp”

override fun onSupportNavigateUp(): Boolean {
    return NavigationUI.navigateUp(navController, drawer_layout)
}

然后执行以上操作。默认情况下，它将处理后退按钮和汉堡包图标。

Android导航组件的“向上按钮”打开抽屉式导航

3 个答案: