java - Android 抽屉布局未显示

Question

我是 Android 开发新手。我正在尝试实现抽屉布局，构建中没有错误，但抽屉汉堡包图标不显示。这是我的 xml 布局

 <LinearLayout
        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"
        android:orientation="vertical"
        tools:context=".MainActivity">

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_height="wrap_content"
            android:layout_width="match_parent"
            android:background="?attr/colorPrimary"
            android:minHeight="?android:attr/actionBarSize"
            />

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

            <TextView
                android:id="@+id/drawer"
                android:text="@string/hello_world"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content" />

            <ListView android:layout_width="240dp"
                android:layout_height="match_parent"
                android:layout_gravity="start"
                />

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

    </LinearLayout>

MainActivity.java

package com.example.arslan.tutsplus02;

import android.content.res.Configuration;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.support.v7.widget.Toolbar;
import android.view.View;

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);

        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) {
                if (getSupportActionBar()!= null ) {
                    getSupportActionBar().setTitle(R.string.drawer_opened);
                }
            }

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

    @Override
    protected void onPostCreate(Bundle savedInstanceState) {
        super.onPostCreate(savedInstanceState);
        mActionBarDrawerToggle.syncState();

    }

    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);
        mActionBarDrawerToggle.onConfigurationChanged(newConfig);
    }

    @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.
        int id = item.getItemId();

        if (mActionBarDrawerToggle.onOptionsItemSelected(item))
        {
            return true;
        }

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

        return super.onOptionsItemSelected(item);
    }
}

谢谢

Answer 1

尝试将 Toolbar 添加到 ActionBarDrawerToggle。

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

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