Android Activity中的方法未定义错误

Question

我正在尝试根据指南制作一个简单的Android应用程序.我使用下面的代码,但它给了我几个错误.在尝试覆盖该onCreate()方法时抱怨.确切的错误如下.谁能解释我在这里犯的错误？

package com.bignerdranch.android.geoquiz;

import android.os.Bundle;

public class CheatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_cheat);
    }

}

确切的错误:

The method onCreate(Bundle) is undefined for the type Object
The method setContentView(int) is undefined for the type CheatActivity
The method onCreate(Bundle) of type CheatActivity must override or implement 
a supertype method  

Answer 1

import android.app.Activity;

public class CheatActivity extends Activity {

您应该从Activity类扩展.因为您只是在没有任何可以从父类重写的方法的情况下创建新类.