BaseAdapter和ListView的设计

步骤：1新建activity_main.xml布局，包括ListView控件

2新建main.xml布局，为每个子控件设置属性

3新建数据源ItemBean类，里面包括子控件需要的东西，

4新建MainActivity类，加载数据源，用List集合，之后初始化适配器，加载适配器

5新建适配器MyAdapt，继承BaseAdapter

 

注意：把xml文件转换为view视图，用View view=LayouInflater.from(context).inflater(R.layout.main,null);

 

Main

package baseadaptdemo.example.administrator.baseadaptdemo;

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

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

public class MainActivity extends AppCompatActivity {
private List<ItemBean> beanList;
    private MyAdapt myAdapt;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ListView listView= (ListView) findViewById(R.id.list_item);
        beanList=new ArrayList<>();
        for (int i=0;i<20;i++){
            beanList.add(new ItemBean(R.mipmap.ic_launcher,
                    "我是标题"+i,
                    "我是内容"+i));
        }
        myAdapt=new MyAdapt(this,beanList);
        listView.setAdapter(myAdapt);
    }
}

ItemBean类

package baseadaptdemo.example.administrator.baseadaptdemo;

import android.widget.ImageView;
import android.widget.TextView;

/**
 * Created by Administrator on 2016/5/9.
 */
/*alt+insert:调用出构造方法*/
public class ItemBean {

    public int itemImageResid;
    public String itemTitle;
    public String itemContent;

    public ItemBean(int itemImageResid, String itemTitle, String itemContent) {
        this.itemImageResid = itemImageResid;
        this.itemTitle = itemTitle;
        this.itemContent = itemContent;
    }
}

MyAdapt

package baseadaptdemo.example.administrator.baseadaptdemo;

import android.content.Context;
import android.provider.Settings;
import android.util.Log;
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;

/**
 * Created by Administrator on 2016/5/9.
 */
public class MyAdapt extends BaseAdapter {
    private List<ItemBean> mList;
    private LayoutInflater mLayoutInflater;

    public MyAdapt(Context context,List<ItemBean> beanList) {
        this.mList=beanList;
        mLayoutInflater=LayoutInflater.from(context);/*为minflater初始化*/
    }

    @Override
    public int getCount() {
        return mList.size();
    }

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

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

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        long start=System.nanoTime();/*获取纳秒时间*/
       /*逗比式*/
        /*View view=mLayoutInflater.inflate(R.layout.main,null);
        ImageView imageView= (ImageView) view.findViewById(R.id.iv_image);
        TextView tv_title= (TextView) view.findViewById(R.id.tv_title);
        TextView tv_context= (TextView) view.findViewById(R.id.tv_context);
        imageView.setImageResource(mList.get(position).itemImageResid);
        tv_title.setText(mList.get(position).itemTitle);
        tv_context.setText(mList.get(position).itemContent);
        return view;*/
        /*普通式*/
        /*if (convertView == null) {
            convertView = mLayoutInflater.inflate(R.layout.main, null);
        }
        ImageView imageView = (ImageView) convertView.findViewById(R.id.iv_image);
        TextView tv_title = (TextView) convertView.findViewById(R.id.tv_title);
        TextView tv_context = (TextView) convertView.findViewById(R.id.tv_context);
        imageView.setImageResource(mList.get(position).itemImageResid);
        tv_title.setText(mList.get(position).itemTitle);
        tv_context.setText(mList.get(position).itemContent);
        return convertView;*/

        ViewHolder viewHolder=null;
        if (convertView == null) {
            convertView = mLayoutInflater.inflate(R.layout.main, null);
            viewHolder=new ViewHolder();
            viewHolder.imageView = (ImageView) convertView.findViewById(R.id.iv_image);
            viewHolder.tv_title = (TextView) convertView.findViewById(R.id.tv_title);
            viewHolder.tv_context = (TextView) convertView.findViewById(R.id.tv_context);
            convertView.setTag(viewHolder);
        }else{
            viewHolder= (ViewHolder) convertView.getTag();
        }

       viewHolder. imageView.setImageResource(mList.get(position).itemImageResid);
       viewHolder. tv_title.setText(mList.get(position).itemTitle);
        viewHolder.tv_context.setText(mList.get(position).itemContent);
        long end= System.nanoTime();
        long dValue=end-start;
        long sum=0;
         sum=sum+dValue;
        Log.d("Main","sum");
        return convertView;


    }
    class ViewHolder{
        public ImageView imageView;
        public TextView tv_title;
        public TextView tv_context;
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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="baseadaptdemo.example.administrator.baseadaptdemo.MainActivity">

    <ListView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/list_item"></ListView>
</RelativeLayout>

main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="match_parent"
    android:layout_height="match_parent"
    >
<ImageView
    android:layout_width="80dp"
    android:layout_height="80dp"
    android:id="@+id/iv_image"
    android:background="@mipmap/ic_launcher"/>
    <TextView
        android:layout_width="match_parent"
        android:layout_height="40dp"
        android:layout_toEndOf="@+id/iv_image"
        android:gravity="center"
        android:textSize="25sp"
        android:id="@+id/tv_title"
        android:text="Title"/>
    <TextView
        android:layout_width="match_parent"
        android:layout_height="40dp"
        android:gravity="center"
        android:id="@+id/tv_context"
        android:layout_below="@+id/tv_title"
        android:layout_toEndOf="@+id/iv_image"
        android:text="context"
        android:textSize="20sp"/><!--layout_below用于设置在一控件之下
        layout_toEndOf用于设置在一控件末尾-->
</RelativeLayout>