导航抽屉汉堡包图标不显示与v7 ActionBarDrawerToggle

Question

我一直在尝试创建一个现有的应用程序的导航抽屉。我已经找到了一些这方面的教程，但其中大部分（包括official Android guide）似乎是针对第4版ActionBarDrawerToggle库，它已被弃用。我试图使用v7库来代替，但我的ActionBarDrawerToggle似乎没有做什么documentation说它应该做的。

编辑：根据下面的答案修改我的代码。汉堡包图标现在可以正确地来回切换，但是当用户点击硬件返回按钮返回到我的应用的主要片段时，汉堡包图标完全消失。为什么会发生？

private void addDrawerItems() { 
    String[] itemArray = {"About", "Nearby", "Settings", "Feedback",}; 
    mAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, itemArray); 
    mDrawerList.setAdapter(mAdapter); 
    mDrawerList.setOnItemClickListener(new AdapterView.OnItemClickListener() { 
     @Override 
     public void onItemClick(AdapterView<?> parent, View view, int position, long id) { 
      Log.d("ContributionsActivity", "Item " + position + " selected"); 
     } 
    }); 
} 

private void setupDrawer() { 
    mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout, R.string.drawer_open, R.string.drawer_close) { 

     /** Called when a drawer has settled in a completely open state. */ 
     public void onDrawerOpened(View drawerView) { 
      super.onDrawerOpened(drawerView); 
      invalidateOptionsMenu(); // creates call to onPrepareOptionsMenu() 
     } 

     /** Called when a drawer has settled in a completely closed state. */ 
     public void onDrawerClosed(View view) { 
      super.onDrawerClosed(view); 
      invalidateOptionsMenu(); // creates call to onPrepareOptionsMenu() 
     } 
    }; 

    mDrawerToggle.setDrawerIndicatorEnabled(true); 
    mDrawerLayout.setDrawerListener(mDrawerToggle); 
} 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setTitle(R.string.title_activity_contributions); 
    setContentView(R.layout.activity_contributions); 

    //Set up navigation drawer 
    getSupportActionBar().setDisplayHomeAsUpEnabled(true); 
    getSupportActionBar().setHomeButtonEnabled(true); 
    mDrawerLayout = (DrawerLayout)findViewById(R.id.drawer_layout); 
    mDrawerList = (ListView)findViewById(R.id.drawer_list); 
    addDrawerItems(); 
    setupDrawer(); 
    ... 
    } 

@Override 
public boolean onOptionsItemSelected(MenuItem item) { 
    // enabling drawer toggle by clicking on the app icon. 
    if (mDrawerToggle.onOptionsItemSelected(item)) { 
     return true; 
    } else { 
     switch (item.getItemId()) { 
      case android.R.id.home: 
       if (mediaDetails.isVisible()) { 
        getSupportFragmentManager().popBackStack(); 
       } 
       return true; 
      default: 
       return super.onOptionsItemSelected(item); 
     } 
    } 
} 

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

Answer 1

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

你错过了同步状态，添加它，一切都应该罚款。