android里getView，inflate，listview问题

今天在写一个listview的时候，遇到一个问题，如下

package com.brookji.funlearn;

import java.util.ArrayList;

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ListView;
import android.widget.TextView;

public class ListViewActivity extends Activity {

    private ListView listView;
    private MyAdapter adapter;
    
    
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_list_view);
        listView = (ListView)findViewById(R.id.listviewlearn);
        ArrayList<String> array = new ArrayList<>();
        array.add("jilichuan");
        array.add("xumeifang");
        adapter = new MyAdapter(this, array);
        listView.setAdapter(adapter);
/*        TextView view = new TextView(this);
        listView.addView(view);
        view.setText("child");*/
        
    
    }
    
    
    public class MyAdapter extends BaseAdapter{
        
        private ArrayList<String> items;
        private Context context;
        
        public MyAdapter(){
            items = new ArrayList<>();
        }
        
        public MyAdapter(Context context, ArrayList<String> items){
            this.context = context;
            this.items = items;
        }
        
        
        @Override
        public int getCount() {
            // TODO Auto-generated method stub
            return items.size();
        }

        @Override
        public Object getItem(int position) {
            // TODO Auto-generated method stub
            return items.get(position);
        }

        @Override
        public long getItemId(int position) {
            // TODO Auto-generated method stub
            return position;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            // TODO Auto-generated method stub
            convertView = ((LayoutInflater)context.getSystemService(context.LAYOUT_INFLATER_SERVICE)).inflate(R.layout.listviewlearn_item_title, null);
            TextView textView = (TextView)convertView.findViewById(R.id.listviewlearn_title);
            textView.setText((String)getItem(position));
            
            return convertView;
        }
        
    }

} 

 这段代码是可以运行的，

但是将倒数的代码

 convertView = ((LayoutInflater)context.getSystemService(context.LAYOUT_INFLATER_SERVICE)).inflate(R.layout.listviewlearn_item_title, null);

 改为

convertView = ((LayoutInflater)context.getSystemService(context.LAYOUT_INFLATER_SERVICE)).inflate(R.layout.listviewlearn_item_title, parent); 

 就会出错，那么就会问：子节点不就是放在listview低下吗？不就是子节点吗？怎么不能这样写呢？

醉深层次的原因我还不知道，但是浅层次的原因是：

在viewgroup中，addview方法不能运用于adapterview，而listview就是一个adapterview，而inflate实现的效果适合add一样的，因此不可以这样，只能设为null。

oncreate方法的最后三行注释掉了，不注释掉，同样会出错！