学习Android——ListView之adapter

package com.example.demo1;

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

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.Gravity;
import android.view.View;
import android.widget.AbsListView;
import android.widget.AbsListView.OnScrollListener;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.Toast;

public class MainActivity extends Activity implements OnItemClickListener,
        OnScrollListener {

    private ListView listview;
    private SimpleAdapter simp_adapter;
    private ArrayAdapter<String> arr_adapter;
    private String[] res = { "苹果", "香蕉", "西瓜" };
    private List<Map<String, Object>> dataList;

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

        // 初始化控件
        listview = (ListView) findViewById(R.id.listView);

        // 新建适配器,并导入数据源
        arr_adapter = new ArrayAdapter<String>(this,
                android.R.layout.simple_list_item_1, res);

        /*SimpleAdapter的参数
         *  1.content:上下文 
         *  2.date:------|数据源List<? extendsMap<String, ?>> data 一个Map组成的list集合 
         *         ------|每一个Map都会去对应ListView列表中的一行
         *         ------|每一个Map(键—值对)中的键必须包含多欧在from中所指的键 
         *  3.resource:列表项的布局文件ID
         *  4.from:Map中的键名 
         *  5.to:绑定数据视图中的ID,与from对应
         */
        dataList = new ArrayList<Map<String, Object>>();*// 注意不要忘了*
        String[] from = { "img", "text" };
        int[] to = { R.id.img, R.id.text };
        simp_adapter = new SimpleAdapter(this, getData(), R.layout.item, from,
                to);
        // 视图加载
        // listview.setAdapter(arr_adapter);
        listview.setAdapter(simp_adapter);
        listview.setOnItemClickListener(this);
        listview.setOnScrollListener(this);
    }

    private List<Map<String, Object>> getData() {
        for (int i = ; i < ; i++) {
            Map<String, Object> map = new HashMap<String, Object>();
            map.put("img", R.drawable.spooky);
            map.put("text", "iPhone" + i);
            dataList.add(map);
        }

        return dataList;
    }

    @Override
    public void onScrollStateChanged(AbsListView view, int scrollState) {
        switch (scrollState) {
        case SCROLL_STATE_FLING:
            Log.i("tag", "手指不动了，但是屏幕还在滚动状态");
            Map<String, Object> map = new HashMap<String, Object>();
            map.put("img", R.drawable.ic_launcher);
            map.put("text", "新增项");
            dataList.add(map);
            simp_adapter.notifyDataSetChanged();// 刷新界面，增加数据源
            break;
        case SCROLL_STATE_TOUCH_SCROLL:
            Log.i("tag", "手指滚动状态");
            break;
        case SCROLL_STATE_IDLE:
            Log.i("tag", "静止状态");
            break;
        default:
            break;
        }
    }

    @Override
    public void onScroll(AbsListView view, int firstVisibleItem,
            int visibleItemCount, int totalItemCount) {

    }

    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
        // 获取列表项位置信息
        String text = listview.getItemAtPosition(position) + "";// int转为String，会产生两个String对象
        // 显示位置信息
        Toast toast = Toast.makeText(this, "text=" + text, Toast.LENGTH_SHORT);
        toast.setGravity(Gravity.CENTER, , );
        toast.show();
    }
}