ListView长按删除信息

package com.hanqi.testapp2;

import android.app.AlertDialog;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.List;

public class Zuoye extends AppCompatActivity {

    ListView lv_3;
    List<MyClass> lm;

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

        lv_3 = (ListView)findViewById(R.id.lv_3);

        lm = new ArrayList<>();

        MyClass myClass = new MyClass(R.drawable.f1,"美食1","美食1的介绍");

        lm.add(myClass);
        lm.add(new MyClass(R.drawable.f2,"美食2","美食2的介绍"));
        lm.add(new MyClass(R.drawable.f2,"美食2","美食2的介绍"));
        lm.add(new MyClass(R.drawable.f2,"美食2","美食2的介绍"));
        lm.add(new MyClass(R.drawable.f2,"美食2","美食2的介绍"));
        lm.add(new MyClass(R.drawable.f2,"美食2","美食2的介绍"));
        lm.add(new MyClass(R.drawable.f2,"美食2","美食2的介绍"));
        lm.add(new MyClass(R.drawable.f2, "美食2", "美食2的介绍"));

        final MyBaseAdapter myBaseAdapter = new MyBaseAdapter();
        lv_3.setAdapter(myBaseAdapter);

        lv_3.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
            @Override
            public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {

                lm.remove(position);

                myBaseAdapter.notifyDataSetChanged();

                return true;
            }
        });

    }

    class MyClass
    {
        private int img;
        private String name;
        private String content;

        public int getImg() {
            return img;
        }

        public void setImg(int img) {
            this.img = img;
        }

        public String getName() {
            return name;
        }

        public void setName(String name) {
            this.name = name;
        }

        public String getContent() {
            return content;
        }

        public void setContent(String content) {
            this.content = content;
        }

        public MyClass(int img, String name, String content)
        {
            this.img = img;
            this.name = name;
            this.content = content;
        }
    }

    class MyBaseAdapter extends BaseAdapter
    {
        @Override
        public int getCount() {
            return lm.size();
        }

        @Override
        public Object getItem(int position) {
            return lm.get(position);
        }

        @Override
        public long getItemId(int position) {
            return 0;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {

            MyClass myClass = lm.get(position);

            View view = View.inflate(Zuoye.this, R.layout.simple_adapter, null);

            ImageView imageView = (ImageView)view.findViewById(R.id.iv_2);
            imageView.setImageResource(myClass.getImg());

            TextView textView = (TextView)view.findViewById(R.id.tv_7);
            textView.setText(myClass.getName());

            TextView textView1 = (TextView)view.findViewById(R.id.tv_8);
            textView1.setText(myClass.getContent());

            return view;
        }

    }
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <ImageView
        android:layout_width="70dp"
        android:layout_height="70dp"
        android:src="@drawable/f1"
        android:id="@+id/iv_2"/>

    <LinearLayout
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:orientation="vertical"
        android:layout_weight="1"
        android:layout_marginLeft="20dp"
        android:gravity="center_vertical">

        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="名字=aaa"
            android:id="@+id/tv_7"/>
        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="内容=aaa"
            android:id="@+id/tv_8"/>


    </LinearLayout>

</LinearLayout>

<?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:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.hanqi.testapp2.Zuoye"
    android:orientation="vertical">


    <ListView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/lv_3"></ListView>

</LinearLayout>