Adapter简单使用步骤_adapter教程

1.创建xml布局: listview的Item要显示的内容(封装bean)

2.创建ItemBean方法,初始化xml中要显示的控件

3.获取要显示的数据格式化为List

4.创建Adapter继承BaseAdapter,完成所有方法

5.在类的初始化函数中声明List并与获取的数据元关联
6.在类的初始化函数中使用传入的context对象对LayoutInflater进行初始化

    private List<ListInfo> mlist;
    private LayoutInflater mInflater;//xml布局填充器
    public ListViewAdapter(Context context,List<ListInfo> list){
        mlist =list;
        mInflater = LayoutInflater.from(context);//通过传入的context对象初始化mInflater
    }
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7.新建ViewHolder类,初始化所有控件Item

public static class ViewHolder {
        TextView tv_title;
        TextView tv_des;
    }
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8.在GetView 方法里用初始化的mInflater加载Item布局对象赋给convertview管理

//使用convertview管理填充布局
    convertView = mInflater.inflate(R.layout.online_listinfo_lay, null);
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9.通过判断covertview对象内是否为空,进行优化
为空则使用findviewById查找出所有控件赋给holder.item

 holder.tv_des = (TextView) convertView.findViewById(R.id.tv_des);
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并为view设置标签
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convertView.setTag(holder);
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不为空则使用gettag获取缓存值:

    holder = (ViewHolder) convertView.getTag();
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10.从list中取出值赋给holder.item

        ListInfo info = mlist.get(position);
        holder.tv_des.setText(info.jarDescript);
        holder.tv_title.setText(info.jarName);
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照虎画猫:

package com.beini.listhelper;

import java.util.List;

import com.beini.uiautom.R;

import android.content.Context;
import android.text.TextUtils;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.EditText;
import android.widget.TextView;

public class ListViewAdapter extends BaseAdapter {
    private List<ListInfo> mlist;
    private LayoutInflater mInflater = null;// xml布局填充器
    private String mTag;

    public ListViewAdapter(Context context, List<ListInfo> list, String tag) {
        mlist = list;
        mInflater = LayoutInflater.from(context);// 通过传入的context对象初始化mInflater
        mTag = tag;
    }

    @Override
    public int getCount() {
        // TODO Auto-generated method stub
        return mlist.size();
    }

    @Override
    public Object getItem(int position) {
        // TODO Auto-generated method stub
        return mlist.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) {
        ViewHolder holder = null;
        if (convertView == null) {
            if (mTag.equals("Online")) {
                // 使用convertview填充布局
                convertView = mInflater.inflate(R.layout.online_listinfo_lay,
                        null);
            } else {
                // 使用convertview填充布局
                convertView = mInflater.inflate(R.layout.local_listinfo_lay,
                        null);
            }
            holder = new ViewHolder();
            holder.tv_des = (TextView) convertView.findViewById(R.id.tv_des);
            holder.tv_title = (TextView) convertView
                    .findViewById(R.id.tv_title);
            // 为view设置标签
            convertView.setTag(holder);
        } else {
            holder = (ViewHolder) convertView.getTag();
        }
        // EditText ed_sx = (EditText) view.findViewById(R.id.ed_sx);
        // EditText ed_cs = (EditText) view.findViewById(R.id.ed_cs);
        ListInfo info = mlist.get(position);
        //区分online和local数据,避免空指针
        if (!TextUtils.isEmpty(info.jarDescript)){
        holder.tv_des.setText(info.jarDescript);}
        holder.tv_title.setText(info.jarName);

        return convertView;
    }

    public static class ViewHolder {
        TextView tv_title;
        TextView tv_des;
    }
}
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