发现的add（）错误没有合适的方法

Question

这是我的代码：

package com.example.wjdrmstn.myapplication; 

import android.support.v4.app.FragmentActivity; 
import android.os.Bundle; 

public class MainActivity extends FragmentActivity { 

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

     if(findViewById(R.id.fragment_container) != null) { 
      if(savedInstanceState != null) 
       return; 

      HeadlinesFragment firstFragment = new HeadlinesFragment(); 
      firstFragment.setArguments(getIntent().getExtras()); 
      getSupportFragmentManager().beginTransaction().add(R.id.fragment_container,firstFragment).commit(); //error occurred 
     } 
    } 
} 

这个代码是从Android开发者网站：
https://developer.android.com/training/basics/fragments/fragment-ui.html

这里是错误：

Error:(20, 59) error: no suitable method found for add(int,HeadlinesFragment) 
method FragmentTransaction.add(Fragment,String) is not applicable 
(argument mismatch; int cannot be converted to Fragment) 
method FragmentTransaction.add(int,Fragment) is not applicable 
(argument mismatch; HeadlinesFragment cannot be converted to Fragment) 

编辑：标题片段代码

package com.example.wjdrmstn.myapplication; 

import android.os.Bundle; 
import android.app.Fragment; 
import android.view.LayoutInflater; 
import android.view.View; 
import android.view.ViewGroup; 

public class HeadlinesFragment extends Fragment { 
    @Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { 
     return inflater.inflate(R.layout.headlines_view, container, false); 
    } 
} 

Answer 1

更改您的进口

import android.app.Fragment; 

到

import android.support.v4.app.Fragment;