Android AlertDialog 构造函数未定义

Question

如果单击“检查帐户”时缺少帐户信息，我会尝试显示一个警告对话框。我在 Eclipse 中收到一个错误，其中 new AlertDialog.Builder(this) 说 constructor AlertDialog.Builder(new View OnClickListener(){}) is undefined。如果我将代码添加到 Activity 的 onCreate 中，代码工作正常。

checkButton.setOnClickListener(new OnClickListener() {
        public void onClick(View Arg0){
            String AccNum = null, Store = null;
            final SharedPreferences settings = getSharedPreferences(CHECK_PREFERENCES, MODE_PRIVATE);

            if (settings.contains("Account") == true){
                AccNum = (settings.getString("Account", "default"));
                Store = (settings.getString("Store", "default"));
            }
            if (AccNum.length() < 7) { 
                AlertDialog alert = new AlertDialog.Builder(this).create();
                alert.setTitle("Account Information missing!");
                alert.setMessage("Enter now? ");

                alert.setButton("Yes", new DialogInterface.OnClickListener() {
                        public void onClick(DialogInterface dialog, int whichButton) {
                            startActivity(new Intent(CheckOrder.this, GoToSetup.class));
                        }
                });
                alert.setButton2("No", new DialogInterface.OnClickListener() {
                        public void onClick(DialogInterface dialog, int whichButton) {
                            return;
                        }
                });
                alert.show();   

            }
        }
});

Answer 1

错误发生是因为 this 是您正在创建的 OnClickListener(在调用 checkButton.setOnClickListener(new OnClickListener(){)，而不是父 Activity。如果您的 Activity 类是 ParentActivity，请尝试以下操作:

AlertDialog alert = new AlertDialog.Builder(ParentActivity.this).create();