使用AlertDialog同步获取文本

Question

如何使用AlertDialog同步获取文本？举例来说，我会想要做这样的事情：

public String GetTextDialog() 
    {   
    final EditText text = new EditText(activity); 

    // Gets the chat 
    final AlertDialog.Builder dialog = new AlertDialog.Builder(activity); 
    dialog.setView(text); 
    dialog.setPositiveButton("Ok", new DialogInterface.OnClickListener() { 
     public void onClick(DialogInterface arg0, int arg1) { 
     } 
    }); 
    dialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() { 
     public void onClick(DialogInterface arg0, int arg1) { 
     } 
    }); 

    // Display 
    dialog.show(); 

    // Return text after dialog is complete 
    return text.getText().toString(); 
    } 

编辑：你会认为这是一个更好的办法：

interface TextHandler 
{ 
    public String Title(); 
    public void HandleText(String text); 
} 

public static boolean ShowTextDialog(
     String title, 
     String defaultValue, 
     final TextHandler posButton, 
     final TextHandler negButton, 
     final TextHandler neutButton, 
     int width 
     ) 
{ 
    // Check for already existing dialog 
    if(showDialog) return false; 
    showDialog = true; 

    // Verify context 
    if(context == null) 
    { 
     Log.e("Crystal", "Screen::ShowTextDialog No Context!"); 
     showDialog = false; 
     return false; 
    } 

    // Verify we have buttons 
    if(neutButton == null) 
    { 
     if(posButton == null || negButton == null) 
     { 
      Log.e("Crystal", "Screen::ShowTextDialog Must supply both postive and negative buttons!"); 
      showDialog = false; 
      return false; 
     } 
    } 
    else 
    { 
     if(posButton != null || negButton != null) 
     { 
      Log.e("Crystal", "Screen::ShowTextDialog Can't have neutral button with other type!"); 
      showDialog = false; 
      return false; 
     } 
    } 

    // Create the dialog 
    AlertDialog.Builder dialog = new AlertDialog.Builder(context); 
    if(title != null) dialog.setTitle(title); 

    // Create the chat 
    final EditText text = new EditText(context); 
    text.setSingleLine(); 
    if(defaultValue != null) text.setText(defaultValue); 
    if(width != 0) text.setWidth((int)(width*context.getResources().getDisplayMetrics().density)); 

    // Add text to dialog 
    dialog.setView(text); 

    if(posButton != null) 
    { 
     dialog.setPositiveButton(posButton.Title(), new DialogInterface.OnClickListener() { 
      public void onClick(DialogInterface arg0, int arg1) { 
       posButton.HandleText(text.getText().toString()); 
       showDialog = false; 
      } 
     }); 
    } 

    if(negButton != null) 
    { 
     dialog.setNegativeButton(negButton.Title(), new DialogInterface.OnClickListener() { 
      public void onClick(DialogInterface arg0, int arg1) { 
       negButton.HandleText(text.getText().toString()); 
       showDialog = false; 
      } 
     }); 
    } 

    if(neutButton != null) 
    { 
     dialog.setNeutralButton(neutButton.Title(), new DialogInterface.OnClickListener() { 
      public void onClick(DialogInterface arg0, int arg1) { 
       neutButton.HandleText(text.getText().toString()); 
       showDialog = false; 
      } 
     }); 
    } 

    // Display 
    dialog.show(); 

    return true; 
} 

而且这样调用：

private void GetUsernameDialog() 
{ 
    ShowTextDialog(
      "Enter Username",             // Title 
      username,               // Default value 
      new TextHandler()             // Positive button 
      { 
       public String Title() { return "Ok"; } 
       public void HandleText(String text) { SetUsername(text); } 
      }, 
      new TextHandler()             // Negative button 
      { 
       public String Title() { return "Cancel"; } 
       public void HandleText(String text) { } 
      }, 
      null,                // Neutral button 
      200                 // Width 
     ); 
} 

Answer 1

你可以在其中有一个Looper的替代线程中运行该对话框，在对话解除时终止循环，让主UI线程等待另一个线程......但是这个是如此复杂的设计，如果你这样做，上帝可能会杀死一只小猫。请问为什么你需要同步数据访问？这只是为了方便，还是你有设计理由？

如果是从对话框设置之前访问状态，那么嵌套的匿名类就是你的答案。上面的代码片段中已经有了这些代码。他们可以自动访问嵌套函数的变量以及嵌套类的成员。