ハンガーアイコンが表示されていないナビゲーションドロワー

Question

小さなアプリでは、ナビゲーションドロワーを使用したいと思っていますが、左矢印キーもハンバーガーアイコンも動作していません...問題を理解してください。

：ここ

MainActivity.java

package com.example.bablu.zoo; 

import android.content.res.Configuration; 
import android.os.Bundle; 
import android.os.PersistableBundle; 
import android.support.design.widget.FloatingActionButton; 
import android.support.design.widget.Snackbar; 
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 android.view.View; 
import android.view.Menu; 
import android.view.MenuItem; 

public class MainActivity extends AppCompatActivity { 

    private DrawerLayout mDrawerLayout; 
    private ActionBarDrawerToggle mActionBarDrawerToggle; 
    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 
     Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); 
     setSupportActionBar(toolbar); 

     // For navigation bar 
     if (getSupportActionBar() != null) { 
      getSupportActionBar().setDisplayShowHomeEnabled(true); 
     } 
     getSupportActionBar().setHomeButtonEnabled(true); 

     mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout); 
     mActionBarDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout, R.string.drawer_opened, R.string.drawer_closed){ 
      @Override 
      public void onDrawerOpened(View drawerView) { 
       super.onDrawerOpened(drawerView); 
       if(getSupportActionBar() != null) 
        getSupportActionBar().setTitle(R.string.drawer_opened); 
       mActionBarDrawerToggle.syncState(); 
      } 

      @Override 
      public void onDrawerClosed(View drawerView) { 
       super.onDrawerClosed(drawerView); 
       if(getSupportActionBar() != null) 
        getSupportActionBar().setTitle(R.string.drawer_closed); 
       mActionBarDrawerToggle.syncState(); 

      } 
     }; 

     mDrawerLayout.addDrawerListener(mActionBarDrawerToggle); 
    } 

    @Override 
    public void onPostCreate(Bundle savedInstanceState) { 
     super.onPostCreate(savedInstanceState); 
     mActionBarDrawerToggle.syncState(); 
     //Call syncState() from your activity's onPostCreate to set the state of the indicator 
     // based on whether the drawerlayout is in open or closed state once the activity 
     // has been restored with onRestoreInstanceState. 
    } 

    @Override 
    public void onConfigurationChanged(Configuration newConfig) { 
     super.onConfigurationChanged(newConfig); 
     mActionBarDrawerToggle.onConfigurationChanged(newConfig); 
     //When the device is rotated the method 'onConfigurationChanged(newConfig' knows when the drawer is open or close. 
    } 

    @Override 
    public boolean onCreateOptionsMenu(Menu menu) { 
     // Inflate the menu; this adds items to the action bar if it is present. 
     getMenuInflater().inflate(R.menu.menu_main, menu); 
     return true; 
    } 

    @Override 
    public boolean onOptionsItemSelected(MenuItem item) { 
     // Handle action bar item clicks here. The action bar will 
     // automatically handle clicks on the Home/Up button, so long 
     // as you specify a parent activity in AndroidManifest.xml. 
     if(mActionBarDrawerToggle.onOptionsItemSelected(item)) 
      return true; 

     int id = item.getItemId(); 

     //noinspection SimplifiableIfStatement 
     if (id == R.id.action_settings) { 
      return true; 
     } 

     return super.onOptionsItemSelected(item); 
    } 
} 

content_main.xml

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout 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" 
    android:orientation="vertical" 
    app:layout_behavior="@string/appbar_scrolling_view_behavior" 
    tools:context="com.example.bablu.zoo.MainActivity" 
    tools:showIn="@layout/activity_main"> 

    <android.support.v4.widget.DrawerLayout 
     android:id="@+id/drawer_layout" 
     android:layout_width="match_parent" 
     android:layout_height="match_parent"> 

     <TextView 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" 
      android:text="Hello world"/> 

     <ListView android:id="@+id/left_drawer" 
      android:layout_width="240dp" 
      android:layout_height="match_parent" 
      android:layout_gravity="start" 
      android:choiceMode="singleChoice" 
      android:divider="@android:color/transparent" 
      android:dividerHeight="0dp" 
      android:background="#111"/> 


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

activity_main.xml

<?xml version="1.0" encoding="utf-8"?> 
<android.support.design.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" 
    android:fitsSystemWindows="true" 
    tools:context="com.example.bablu.zoo.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> 

    <include layout="@layout/content_main" /> 

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

は、下の写真は、 10回の

ありがとう！あなたのコードで

Answer 1

toolbar

を追加しますが、このよう

mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout); 
    mActionBarDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout, toolbar, R.string.drawer_opened, R.string.drawer_closed)