五分钟学会之ListView<simpleAdapter><BaseAdapter>

package com.coderqi.android2lesson_02_simpleadapter;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.ListView;
import android.widget.SimpleAdapter;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

//simpleAdapter是一种基本版的完整的列表视图
public class MainActivity extends AppCompatActivity {
// simpleAdapter可以进行布局文件定制，从而达到自定义的效果

//    simpleAdapter 步骤1:创建一个布局文件，用来给每一个Item（cell）进行布局
//    listview在iOS开发里面叫UITableView
//    iOS里面没有包的概念，有命名空间
//    simpleAdapter 步骤2：
//    在MainActivity布局文件中添加ListView
//    simpleAdapter 步骤三：
//    声明属性并且进行初始化
private ListView mlistView;

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

//        进行初始化
mlistView =(ListView) findViewById(R.id.listView);
//        simpleAdapter 步骤4：
//        创建一个simple适配器
//        参数1：是传递的一个上下文对象；
//        参数2：要显示的数据
//        参数3：数据显示的布局文件；
//        参数4：数据提取时用到的关键字；
//        参数5：数据对应额布局文件中的控件ID
SimpleAdapter adapter =new SimpleAdapter(this,getData(), R.layout. ,new String[]{"image","title","info"},
new int[]{R.id.image,R.id.title,R.id.info});

//        simpleLeAdapter步骤5：将adapter和listview进行绑定
mlistView.setAdapter(adapter);
}
//    在这个方法里面进行数据的创建和初始化，拼装要显示的数据
private List<Map<String,Object>> getData(){
List<Map<String,Object>>list =new ArrayList<>();
Map<String,Object>map =new HashMap<>();
map.put("image", R.drawable.ic_launcher);
map.put("title","在水一方");
map.put("info","伊人却已不在");
list.add(map);
Map<String,Object>map1 =new HashMap<>();

map1.put("image",R.drawable.ic_launcher);
map1.put("title","核舟记");
map1.put("info","麻雀虽小");
list.add(map1);

Map<String,Object>map2 =new HashMap<>();

map2.put("image",R.drawable.ic_launcher);
map2.put("title","藤蔓");
map2.put("info","爬墙虎");
list.add(map2);
return  list;
}
}
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">

<ImageView
android:id="@+id/image"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="5px"/>

<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical"
>

<TextView
android:id="@+id/title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="22px"
android:text="山茶花下"
/>
<TextView
android:id="@+id/info"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="15px"
android:text="伊人微醺"
/>

</LinearLayout>
</LinearLayout>

******************************************************************************************

BaseAdapter

package com.example.user.android2lesson_day3_baseadapter;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.ListView;

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

import bean.News;

public class MainActivity extends AppCompatActivity {
//baseAdapter使用
//    1.创建一个布局文件，对Item的控件进行布局
//    2.在对应的Activity中添加ListView控件
//    3.声明属性，并进行初始化
//    4.创建一个类，继承自BaseAdapter
//    5.创建Adapter并进行绑定
private ListView mlistView;
@Override

protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mlistView = (ListView) findViewById(R.id.listView);

//
//创建Adapter并进行绑定
MyAdapter adapter =new MyAdapter(this,getData());
mlistView.setAdapter(adapter);

}
private List<News>getData(){
List<News>list =new ArrayList<>();
News new1 =new News(R.drawable.qwe,"企鹅","么么哒");
list.add(new1);
News new2 =new News(R.drawable.asd,"女生","么么哒");
list.add(new2);
News new3 =new News(R.drawable.zxc,"老司机","么么哒");
list.add(new3);

News new4 =new News(R.drawable.qwe,"企鹅","么么哒");
list.add(new4);
News new5 =new News(R.drawable.asd,"女生","么么哒");
list.add(new5);
News new6 =new News(R.drawable.zxc,"老司机","么么哒");
list.add(new6);
News new7 =new News(R.drawable.qwe,"企鹅","么么哒");
list.add(new7);
News new8 =new News(R.drawable.asd,"女生","么么哒");
list.add(new8);
News new9 =new News(R.drawable.zxc,"老司机","么么哒");
list.add(new9);
return  list;
}
}



package com.example.user.android2lesson_day3_baseadapter;

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

import java.util.List;

import bean.News;

/**
* Created by user on 2016/7/6.
*/
public class MyAdapter extends BaseAdapter {
//    4.1声明属性，保存数据和上下文对象
private List<News>list;
private Context context;

public  MyAdapter(Context context,List<News>list){
this.list=list;
this.context=context;
}
@Override
public int getCount() {
return list.size();
}

@Override
public Object getItem(int i) {
return list.get(i);
}

@Override
//    获取Item对应的ID
public long getItemId(int i) {
return i;
}

@Override
//    最最最关键的！！！！  获取i对应位置的视图
public View getView(int i, View view, ViewGroup viewGroup
) {
//        优化前的方式！！！！！！！！
//        去获取指定的layout文件中指定id的控件
//        View v=LayoutInflater.from(context).inflate(R.layout.item_layout,null);
//        ImageView imageView = (ImageView) v.findViewById(R.id.image);
//        TextView titleView= (TextView) v.findViewById(R.id.text1);
//        TextView infoView = (TextView) v.findViewById(R.id.text2);
////        拿到我们的数据
//        News news = (News) getItem(i);
////        根据数据对界面进行赋值
//imageView.setBackgroundResource(news.getImg());
//        titleView.setText(news.getTitle().toString());
//        infoView.setText(news.getInfo().toString());
//        return v;
//        优化后的方式！！！！！！！
//        利用缓存
ViewHolder  holder;
if (view ==null){
//            将指定的布局文件转换成视图对象

//            这里是缓存的界面控件
view =View.inflate(context,R.layout.item_layout,null);
holder =new  ViewHolder();
holder.imageView=(ImageView) view.findViewById(R.id.image);
//            ImageView image = (ImageView) view.findViewById(R.id.image);
holder . titleView= (TextView) view.findViewById(R.id.text1);
holder. InfoView= (TextView) view.findViewById(R.id.text2);
view.setTag(holder);

}else {holder = (ViewHolder) view.getTag();

}  News news = (News) getItem(i);
holder. imageView.setBackgroundResource(news.getImg());
holder. titleView.setText(news.getTitle().toString());
holder.InfoView.setText(news.getInfo().toString());
return  view;
}
}

***************************************************************************************

package bean;

/**
* Created by user on 2016/7/6.
*/
public class News {
//    存放图片,资源都是采用id的形式存储
private  int img;
private  String title;
private  String info;

//    初始化赋值方法
public News(int img,String title,String info){
this.img =img;
this.title=title;
this.info=info;
}

public int getImg() {
return img;
}

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

public String getTitle() {
return title;
}

public void setTitle(String title) {
this.title = title;
}

public String getInfo() {
return info;
}

public void setInfo(String info) {
this.info = info;
}
}