NavigationDrawer图标没有显示出来 [英] NavigationDrawer icon not showing up

问题描述

我在执行 NavigationDrawer 的一个很简单的例子。该示例工作正常，但我有一个奇怪的问题。对于NavigationDrawer图标（一般 ic_drawer ）不会在动作条显示出来。我已经使用不同的图标图像试过，但并没有达到预期的结果。这里的code。该项目只有一个名为活动 MainActivity.java 。

 公共类MainActivity延伸活动{私人DrawerLayout mDrawerLayout;
私人的ListView mListView;
私人ActionBarDrawerToggle mDrawerToggle;
私有String []数组=新的String [] {你好，HOLA，合十礼
        赛俩目};@覆盖
保护无效的onCreate（捆绑savedInstanceState）{
    super.onCreate（savedInstanceState）;
    的setContentView（R.layout.activity_main）;    mDrawerLayout =（DrawerLayout）findViewById（R.id.drawer）;
    mListView =（ListView控件）findViewById（R.id.list）;    getActionBar（）setDisplayHomeAsUpEnabled（真）。
    ArrayAdapter＆LT;串GT;适配器=新ArrayAdapter＆LT;串GT;（
            getApplicationContext（），
            android.R.layout.simple_dropdown_item_1line，数组）;
    mListView.setAdapter（适配器）;
    mListView.setOnItemClickListener（新OnItemClickListener（）{
        @覆盖
        公共无效onItemClick（适配器视图＆LT;＆GT;为arg0，ARG1观，诠释ARG2，
                长ARG3）{
            Toast.makeText（getApplicationContext（），数组[ARG2]
                    Toast.LENGTH_SHORT）.show（）;        }
    }）;    mDrawerToggle =新ActionBarDrawerToggle（这一点，mDrawerLayout，
            R.drawable.ic_drawer，R.string.open，R.string.close）{
        @覆盖
        公共无效onDrawerClosed（查看drawerView）{
            // TODO自动生成方法存根            invalidateOptionsMenu（）;
        }        @覆盖
        公共无效onDrawerOpened（查看drawerView）{
            // TODO自动生成方法存根            invalidateOptionsMenu（）;
        }
    };
    mDrawerLayout.setDrawerListener（mDrawerToggle）;
}@覆盖
公共布尔onCreateOptionsMenu（菜单菜单）{
    //充气菜单;如果是present这增加了项目操作栏。
    。getMenuInflater（）膨胀（R.menu.main，菜单）;
    返回true;
}@覆盖
公共布尔onOptionsItemSelected（菜单项项）{
    // TODO自动生成方法存根    如果（mDrawerToggle.onOptionsItemSelected（项目））
        返回true;
    返回super.onOptionsItemSelected（项目）;
}}
 

如果我注释掉与code getActionBar（）行setDisplayHomeAsUpEnabled（真）; 中，code停止工作，这意味着 NavigationDrawer 不开。

有关参考，此活动的XML布局是：

  

activity_main.xml中

 ＆LT; android.support.v4.widget.DrawerLayout
的xmlns：机器人=htt​​p://schemas.android.com/apk/res/android
        机器人：ID =@ + ID /抽屉
        机器人：layout_width =match_parent
        机器人：layout_height =match_parent＆GT;    ＆LT;的TextView
        机器人：ID =@ + ID /帧
        机器人：layout_width =match_parent
        机器人：layout_height =match_parent
        机器人：文本=更改aaaega，哼哼laaenge/＆GT;    ＆LT; ListView控件
        机器人：ID =@ + ID /列表
        机器人：layout_width =240dp
        机器人：layout_height =match_parent
        机器人：layout_gravity =开始
        机器人：choiceMode =singleChoice/＆GT;＆LT; /android.support.v4.widget.DrawerLayout>
 

有什么建议？

感谢。

解决方案

在程序中包含code的这一部分，

  @覆盖
    保护无效onPostCreate（捆绑savedInstanceState）{
        super.onPostCreate（savedInstanceState）;
        //同步onRestoreInstanceState后切换状态已经发生。
        mDrawerToggle.syncState（）;
    }    @覆盖
    公共无效onConfigurationChanged（配置NEWCONFIG）{
        super.onConfigurationChanged（NEWCONFIG）;
        mDrawerToggle.onConfigurationChanged（NEWCONFIG）;
    }
    @覆盖
    公共布尔onOptionsItemSelected（菜单项项）{        //调用mDrawerToggle.onOptionsItemSelected（），如果返回true
        //那么它处理的应用程序图标触摸事件        如果（mDrawerToggle.onOptionsItemSelected（项目））{
            返回true;
        }
        返回super.onOptionsItemSelected（项目）;
    }
 

I am implementing a very simple example of NavigationDrawer. The example works fine, but I have a strange problem. The icon for NavigationDrawer (generally ic_drawer) does not show up in the ActionBar. I have tried using different icon images, but didn't achieved the desired result. Here's the code. The project has only one activity named MainActivity.java.

public class MainActivity extends Activity {

private DrawerLayout mDrawerLayout;
private ListView mListView;
private ActionBarDrawerToggle mDrawerToggle;
private String[] array = new String[] { "Hello", "hola", "namaste",
        "salaam" };

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer);
    mListView = (ListView) findViewById(R.id.list);

    getActionBar().setDisplayHomeAsUpEnabled(true);
    ArrayAdapter<String> adapter = new ArrayAdapter<String>(
            getApplicationContext(),
            android.R.layout.simple_dropdown_item_1line, array);
    mListView.setAdapter(adapter);
    mListView.setOnItemClickListener(new OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
                long arg3) {
            Toast.makeText(getApplicationContext(), array[arg2],
                    Toast.LENGTH_SHORT).show();

        }
    });

    mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout,
            R.drawable.ic_drawer, R.string.open, R.string.close) {
        @Override
        public void onDrawerClosed(View drawerView) {
            // TODO Auto-generated method stub

            invalidateOptionsMenu();
        }

        @Override
        public void onDrawerOpened(View drawerView) {
            // TODO Auto-generated method stub

            invalidateOptionsMenu();
        }
    };
    mDrawerLayout.setDrawerListener(mDrawerToggle);
}

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

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // TODO Auto-generated method stub

    if (mDrawerToggle.onOptionsItemSelected(item))
        return true;
    return super.onOptionsItemSelected(item);
}

}

And if I comment out the line with code getActionBar().setDisplayHomeAsUpEnabled(true);, the code stops working, meaning NavigationDrawer does not open.

For reference, the xml layout for this activity is:

activity_main.xml

<android.support.v4.widget.DrawerLayout 
xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/drawer"
        android:layout_width="match_parent"
        android:layout_height="match_parent" >

    <TextView
        android:id="@+id/frame"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="change aaaega, hum laaenge" />

    <ListView
        android:id="@+id/list"
        android:layout_width="240dp"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        android:choiceMode="singleChoice" />

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

Any suggestions ?

Thanks.

解决方案

Include this part of code in your program,

@Override
    protected void onPostCreate(Bundle savedInstanceState) {
        super.onPostCreate(savedInstanceState);
        // Sync the toggle state after onRestoreInstanceState has occurred.
        mDrawerToggle.syncState();
    }

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


    @Override
    public boolean onOptionsItemSelected(MenuItem item) {

        // call mDrawerToggle.onOptionsItemSelected(), if it returns true
        // then it has handled the app icon touch event

        if (mDrawerToggle.onOptionsItemSelected(item)) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

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