Java 无法在android中启动AlertDialog box

我正在尝试在单击按钮时实现AlertDialogBox。但是我不知道为什么AlertDialog对话框不能启动。以下是我迄今为止的编码：

netbalrefreshbtn = (Button) findViewById(R.id.netbalrefreshbtn);
        netbalrefreshbtn.setOnClickListener(new OnClickListener()
        {
            @Override
            public void onClick(View v) 
            {
                // TODO Auto-generated method stub
                AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(getApplicationContext());
                alertDialogBuilder.setMessage(" Update Values")
                                  .setPositiveButton("Ok", new DialogInterface.OnClickListener() 
                                  {
                                    @Override
                                    public void onClick(DialogInterface dialog, int which) 
                                    {
                                        // TODO Auto-generated method stub
//                                      if(selecteditem == "Missed Call")
//                                      {
                                            String url = "tel:123456";
                                            Intent intent = new Intent(Intent.ACTION_CALL, Uri.parse(url));
                                            startActivity(intent);
//                                      }

                                    }
                                })
                                .setNegativeButton("Cancel", new DialogInterface.OnClickListener() 
                                {   
                                    @Override
                                    public void onClick(DialogInterface dialog, int which) 
                                    {
                                        // TODO Auto-generated method stub
                                        dialog.dismiss();
                                    }
                                });
                AlertDialog alertDialog = alertDialogBuilder.create();
                alertDialog.show();
            }
        });

我调试了代码，它给了我以下错误：

03-23 13:59:36.450: E/AndroidRuntime(16221): android.view.WindowManager$BadTokenException: Unable to add window -- token null is not valid; is your activity running?
03-23 13:59:36.450: E/AndroidRuntime(16221):    at android.view.ViewRootImpl.setView(ViewRootImpl.java:562)
03-23 13:59:36.450: E/AndroidRuntime(16221):    at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:282)
03-23 13:59:36.450: E/AndroidRuntime(16221):    at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:85)
03-23 13:59:36.450: E/AndroidRuntime(16221):    at android.app.Dialog.show(Dialog.java:298)
03-23 13:59:36.450: E/AndroidRuntime(16221):    at com.techfrk.fetchinboxsms.IciciBank$1.onClick(IciciBank.java:86)

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有什么想法吗？

您的问题是使用

getApplicationContext（）

as<代码>AlertDialog.Builder只需要活动上下文。这是一个很好的解释

替换

AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(getApplicationContext());

与

---

希望它对您有用。

发布您的完整代码完整的代码很长。我已经实现了许多其他的东西。这是我刚才添加的部分，它给了我一个错误！！不客气。如果对你有用，请将其标记为正确答案。谢谢

AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(YourActivity.this);