ListView的数据更新问题

package com.example.listviewupdate;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageButton;
import android.widget.ImageView;
import android.widget.TextView;

import java.util.LinkedList;
import java.util.zip.Inflater;

/**
 * Created by yuwei on 2016/11/2.
 */
public class MyBaseAdapter extends BaseAdapter {
    private Context context;
    private LinkedList<Data> mData;         //  LinkList是由链表实现的，在插入和删除数据方面优于ArrayList
    private Inflater inflater;
    public MyBaseAdapter(Context context ,LinkedList<Data> mData){
        this.context = context;
        this.mData = mData;
    }

    public void add(Data data) {            //按顺序增加一条数据
        if (mData == null) {
            mData = new LinkedList<>();
        }
        mData.add(data);
        notifyDataSetChanged();
    }

    public void add(int position,Data data){    //在第position个位置增加数据
        if (mData == null) {
            mData = new LinkedList<>();
        }
        mData.add(position,data);
        notifyDataSetChanged();
    }

    public void remove(int position){
        if(mData != null) {
            mData.remove(position);
        }
        notifyDataSetChanged();
    }

    public void remove(Data data){
        if(mData != null) {
            mData.remove(data);
            System.out.println("删除成功");
        }
        notifyDataSetChanged();
    }
    @Override
    public int getCount() {
        return mData.size();
    }

    @Override
    public Object getItem(int position) {
        return null;                    //  注意这里是空 getItem方法不是在Baseadapter类中被调用的，而是在Adapterview中被调用的。在这个方法中调用
                                        // getItemAtPosition
                                        // 么getItemAtPosition(position) 又是什么时候被调用？答案：它也不会被自动调用，它是用来在我们设置

                                        //setOnItemClickListener、setOnItemLongClickListener、setOnItemSelectedListener的点击选择处理事件中方便地调用

                                         // 来获取当前行数据的。
    }

    @Override
    public long getItemId(int position) {
        return position;
                                        //注意这里返回的是position 不同getItem的是，
                                        // 某些方法（如onclicklistener的onclick方法）有id这个参数，而这个id参数就是取决于getItemId()这个返回值的。
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder = null;
        if(convertView == null){
            convertView = LayoutInflater.from(context).inflate(R.layout.list_item,parent,false);
            holder = new ViewHolder();
            holder.imageView = (ImageView) convertView.findViewById(R.id.img_icon);
            holder.textView = (TextView) convertView.findViewById(R.id.txt_content);
            convertView.setTag(holder);
        }else{
            holder = (ViewHolder) convertView.getTag();
        }

        holder.imageView.setImageResource(mData.get(position).getImgId());
        holder.textView.setText(mData.get(position).getContent());
        return convertView;

    }

    class ViewHolder{
        private ImageView imageView;
        private TextView textView;

    }


}

package com.example.listviewupdate;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ListView;
import android.widget.TextView;

import java.util.LinkedList;
import java.util.List;

public class MainActivity extends AppCompatActivity {
    private MyBaseAdapter baseAdapter;
    private ListView listView;
    private List<Data> mData = null;
    private Data mData_5 = null;
    private TextView txt_empty;
    private Button button;
    private Button button1;
    private Button button2;
    private Button button3;
    private int flag=0;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        bindViews();
        mData = new LinkedList<Data>();
        baseAdapter = new MyBaseAdapter(MainActivity.this ,(LinkedList<Data>)mData ); //注意强制类型转换
        listView.setAdapter(baseAdapter);
        txt_empty = (TextView) findViewById(R.id.txt_empty);
        txt_empty.setText("暂无数据~");                                                 //增加用户的体验效果，当没有数据时显示空
        listView.setEmptyView(txt_empty);
        button.setOnClickListener(onClickListener);
        button1.setOnClickListener(onClickListener);
        button2.setOnClickListener(onClickListener);
        button3.setOnClickListener(onClickListener);
    }

    View.OnClickListener onClickListener = new View.OnClickListener() {
        @Override
        public void onClick(View v) {                               //增加数据
            switch (v.getId()){
                case R.id.add_data:
                   mData_5 = new Data(R.mipmap.ic_launcher,"给猪哥跪了~~~ x " + flag);
                    baseAdapter.add(mData_5);
                            flag++;
                    break;
                case R.id.add_data1:
                    baseAdapter.add(5,new Data(R.mipmap.ic_launcher,"给猪哥跪了~~~ x " + 5));
                    break;
                case R.id.add_data2:

                    baseAdapter.remove(mData_5);                    //这里删除的是上一个增加的mData_5
                    System.out.println(mData_5.getContent());
                    break;
                case R.id.add_data3:
                    baseAdapter.remove(5);
                    break;
            }
        }
    };

    private void bindViews() {
        listView = (ListView)findViewById(R.id.lv);
        button = (Button)findViewById(R.id.add_data);
        button1 = (Button)findViewById(R.id.add_data1);
        button2 = (Button)findViewById(R.id.add_data2);
        button3 = (Button)findViewById(R.id.add_data3);

    }

}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">
    <Button
        android:id="@+id/add_data"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="增加"/>

    <Button
        android:id="@+id/add_data1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="增加特定位置"/>
    <Button
        android:id="@+id/add_data2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="删除"/>

    <Button
        android:id="@+id/add_data3"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="删除特定位置"/>
    <ListView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/lv">

    </ListView>
    <TextView
        android:id="@+id/txt_empty"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:textSize="15pt"
        android:textColor="#000000"/>


</LinearLayout>