點擊後顯示菜單按鈕：爲什麼我的代碼不工作？

Question

我有一個片段與一個單一的Button。我的目標是每當用戶點擊該按鈕時顯示menu_language.xml。我試圖找到一個在線答案，這是最接近我可以得到它...但它不工作：如果我按下按鈕沒有任何反應。這段代碼有什麼問題？

@Nullable 
    @Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { 
     View fgm = inflater.inflate(R.layout.fragment_settings, container, false); 
     Button changeLanguageBtn = (Button) fgm.findViewById(R.id.change_language_button); 
     changeLanguageBtn.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View view) { 
       getActivity().openOptionsMenu(); 
      } 
     }); 
     return fgm; 
    } 

    @Override 
    public void onCreateContextMenu(ContextMenu menu, View view, ContextMenu.ContextMenuInfo menuInfo) { 
     super.onCreateContextMenu(menu, view, menuInfo); 
     if (view.getId() == R.id.change_language_button) { // is this even necessary? 
      MenuInflater inflater = getActivity().getMenuInflater(); 
      inflater.inflate(R.menu.menu_language, menu); 
     } 
    } 

    @Override 
    public boolean onContextItemSelected(MenuItem item) { 
     switch (item.getItemId()) { 
      case R.id.action_english: 
       // switch to English 
       return true; 
      case R.id.action_italian: 
       // switch to Italian 
       return true; 
      case R.id.action_french: 
       // switch to French 
       return true; 
      default: 
       return super.onContextItemSelected(item); 
     } 
    } 

這是菜單的XML：

<?xml version="1.0" encoding="utf-8"?> 
<menu xmlns:android="http://schemas.android.com/apk/res/android"> 

    <group android:checkableBehavior="single"> 
     <item 
      android:id="@+id/action_italian" 
      android:title="@string/italian" /> 
     <item 
      android:id="@+id/action_english" 
      android:title="@string/english" /> 
     <item 
      android:id="@+id/action_french" 
      android:title="@string/french" /> 
    </group> 
</menu> 

Answer 1

您需要實現選項菜單，你實現上下文菜單。

see instructions here

Answer 2

我覺得你有錯誤的方法（如果你想添加到ActionBar的菜單：如果你讀這個方法的Javadoc

public void onCreateContextMenu(ContextMenu menu, View view, ContextMenu.ContextMenuInfo menuInfo) 

：

​​

而：

public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {

說：

/** 
    * Initialize the contents of the Activity's standard options menu. You 
    * should place your menu items in to <var>menu</var>. For this method 
    * to be called, you must have first called {@link #setHasOptionsMenu}. See 
    * {@link Activity#onCreateOptionsMenu(Menu) Activity.onCreateOptionsMenu} 
    * for more information. 
    * 
    * @param menu The options menu in which you place your items. 
    * 
    * @see #setHasOptionsMenu 
    * @see #onPrepareOptionsMenu 
    * @see #onOptionsItemSelected 
    */ 

所以，如果你想菜單添加到活動中，你必須以後使用。現在，如果您想顯示一個上下文菜單錨定到您按下的按鈕，然後查看PopupMenu類。

關於你的is this needed?評論，答案是最有可能沒有你的情況。