Android

Question

我正在尝试在我的 Android (Kotlin) 应用程序中构建汉堡菜单。我以为我遵循了所有步骤，但只有后退箭头显示，什么都不做。但是我可以从左边滑动菜单。

然后我启动了一个新的应用程序并尝试从头开始，结果相同。再次显示状态栏，只有后退箭头。

我似乎找不到我做错了什么。

这是我的代码

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.drawerlayout.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">

    <include
        layout="@layout/app_bar_main"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <fragment
            android:id="@+id/nav_host_fragment"
            android:name="androidx.navigation.fragment.NavHostFragment"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            app:defaultNavHost="true"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintRight_toRightOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            app:navGraph="@navigation/nav_graph" />
    </androidx.constraintlayout.widget.ConstraintLayout>

    <com.google.android.material.navigation.NavigationView
        android:id="@+id/nav_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/drawer_menu" />

</androidx.drawerlayout.widget.DrawerLayout>

mainActivity.kt

package com.wensline.myapplication

import android.os.Bundle

import androidx.appcompat.app.AppCompatActivity
import androidx.appcompat.widget.Toolbar
import androidx.drawerlayout.widget.DrawerLayout
import androidx.navigation.findNavController
import androidx.navigation.fragment.NavHostFragment.findNavController
import androidx.navigation.ui.AppBarConfiguration
import androidx.navigation.ui.navigateUp
import androidx.navigation.ui.setupActionBarWithNavController
import androidx.navigation.ui.setupWithNavController
import com.google.android.material.navigation.NavigationView

class MainActivity : AppCompatActivity() {

    private lateinit var appBarConfiguration: AppBarConfiguration

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        val toolbar: Toolbar = findViewById(R.id.toolbar)
        setSupportActionBar(toolbar)
        ///
        val drawerLayout: DrawerLayout = findViewById(R.id.drawer_layout)
        val navView: NavigationView = findViewById(R.id.nav_view)
        val navController = findNavController(R.id.nav_host_fragment)
        // Passing each menu ID as a set of Ids because each
        // menu should be considered as top level destinations.
        appBarConfiguration = AppBarConfiguration(setOf(
            R.id.nav_home, R.id.nav_gallery, R.id.nav_slideshow), drawerLayout)
        setupActionBarWithNavController(navController, appBarConfiguration)
        navView.setupWithNavController(navController)

    }


    override fun onSupportNavigateUp(): Boolean {
        val navController = findNavController(R.id.nav_host_fragment)
        return navController.navigateUp(appBarConfiguration) || super.onSupportNavigateUp()
    }
}

app_bar_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.coordinatorlayout.widget.CoordinatorLayout 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">

    <com.google.android.material.appbar.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/Theme.AppCompat.Light.DarkActionBar">

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

    </com.google.android.material.appbar.AppBarLayout>

</androidx.coordinatorlayout.widget.CoordinatorLayout>

Answer 1

你需要设置ActionBarDrawerToggle来实现这个-

private lateinit var drawerToggle: ActionBarDrawerToggle

在 onCreate 方法中你需要初始化 drawerToggle 如下 -

drawerToggle = ActionBarDrawerToggle(this, drawer, toolbar, 
R.string.navigation_drawer_open, R.string.navigation_drawer_close)
drawer.addDrawerListener(toggle)
toggle.setDrawerIndicatorEnabled(true)
toggle.syncState()

Answer 2

更改这行代码

 setupActionBarWithNavController(navController, appBarConfiguration)

对此

 toolbar.setupWithNavController(navController, appBarConfiguration)

Answer 3

感谢您的建议。 @KakyireLastBorn 的回答给了我一个想法。我换了行

setupActionBarWithNavController(navController, appBarConfiguration)

至

 toolbar.setupWithNavController(navController, drawerLayout)

这解决了问题！

Android - DrawerLayout 仅显示后退箭头

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