未顯示Android警報對話框

Question

我從Activity的onPostResume方法創建並顯示警報對話框。 對話框沒有顯示，但我不明白爲什麼。

我對顯示的對話框代碼：

AlertDialog.Builder builder = new AlertDialog.Builder(this); 
builder.setMessage("message"); 
builder.setPositiveButton("a", aListener); 
builder.setPositiveButton("b", bListener); 
builder.setCancelable(false); 

AlertDialog dlg = builder.create(); 
dlg.show(); 

Answer 1

嘗試使用：

AlertDialog.Builder builder = new AlertDialog.Builder(this); 
builder.setMessage("message"); 
builder.setPositiveButton("a", aListener); 
builder.setPositiveButton("b", bListener); 
builder.setCancelable(false); 
builder.show(); 

注：沒有理由創建另一個AlertDialog實例。

---

或者你可以創建方法，另一種正確的做法，返回新AlertDialog：

protected static final int CREATE_INFORMATION_DIALOG = 1320; 

private Dialog createDialog(int type) { 
     AlertDialog dialog = null; 
     switch (type) { 
      case CREATE_INFORMATION_DIALOG: 
       dialog = new AlertDialog.Builder(this) 
        .setTitle("Information") 
        .setMessage("Download was finished successfully.") 
        .setPositiveButton("Close", new DialogInterface.OnClickListener() { 
         public void onClick(DialogInterface dlg, int whichButton) { 

         } 
        }) 
        .create(); 
       break; 
     } 
     return dialog; 
    } 

然後就是這樣稱呼它

createDialog(CREATE_INFORMATION_DIALOG).show();