android ListView下拉刷新之头布局的完成

首先要在listview添加一个头布局，

然后进行隐藏，

再进行touch监听，显示头布局

package com.example.listviewf5;

import android.content.Context;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.widget.ListView;

public class MyListView extends ListView {
    private View v;
    private int headHeight;// 头部的高度
    private int downY;// 按下时候Y坐标

    public MyListView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        // TODO Auto-generated constructor stub
        initView(context);
    }

    public MyListView(Context context, AttributeSet attrs) {
        super(context, attrs);
        // TODO Auto-generated constructor stub
        initView(context);
    }

    public MyListView(Context context) {
        super(context);
        // TODO Auto-generated constructor stub
        initView(context);
    }

    /**
     * 加载顶部布局文件
     * 
     * @param context
     */
    private void initView(Context context) {
        // LayoutInflater in =LayoutInflater.from(context);
        // v = in.inflate(R.layout.head,null);
        v = View.inflate(context, R.layout.head, null);
        this.addHeaderView(v);
        v.measure(0, 0);// 通知系统测量宽高
        headHeight = v.getMeasuredHeight();// 得到测量后的高度
        v.setPadding(0, -headHeight, 0, 0);// 进行隐藏head,就是把paddingtop设置成负高度

    }

    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        switch (ev.getAction()) {
        case MotionEvent.ACTION_DOWN:
            downY = (int) ev.getY();
            break;
        case MotionEvent.ACTION_MOVE:
            int deltaY = (int) (ev.getY() - downY);//得到移动的距离
            int currentHeight = -headHeight + deltaY;
            //判断当前的距离是不是大于headHeight 并且显示的是第一个位置
            if(currentHeight>-headHeight && getFirstVisiblePosition()==0){
                v.setPadding(0, currentHeight, 0, 0);//展现头部
                return true;//拦截事件不让listview处理
            }
            break;
        case MotionEvent.ACTION_UP:
            break;
        }
        return super.onTouchEvent(ev);
    }
    
    

}

<?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="match_parent"
    android:orientation="vertical" >

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:paddingBottom="10dp"
        android:paddingTop="10dp"
        android:layout_gravity="center_horizontal" >

        <LinearLayout
            android:id="@+id/ll"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerInParent="true"
            android:gravity="center"
            android:orientation="vertical" >

            <TextView
                android:id="@+id/head_tv"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="下拉可以刷新" />

            <TextView
                android:id="@+id/head_tvtime"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="上次刷新时间" />
        </LinearLayout>

        <ImageView
            android:id="@+id/head_img"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginRight="20dp"
            android:layout_toLeftOf="@+id/ll"
            android:src="@drawable/ic_launcher" />

        <ProgressBar
            android:id="@+id/pb"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginRight="20dp"
            android:layout_toLeftOf="@+id/ll"
            android:visibility="gone" />
    </RelativeLayout>

</LinearLayout>

<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"
    tools:context=".MainActivity" >

    <com.example.listviewf5.MyListView
        android:id="@+id/lv"
        android:layout_width="match_parent"
        android:layout_height="match_parent" 
        android:scrollbars="none"/>

</RelativeLayout>

package com.example.listviewf5;

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

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.widget.ListView;
import android.widget.SimpleAdapter;

public class MainActivity extends Activity {
    private MyListView lv;
    private List<Map<String, Object>> list;
    private SimpleAdapter sa;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        lv = (MyListView) findViewById(R.id.lv);
        list = new ArrayList<Map<String,Object>>();
        for (int i = 0; i <20; i++) {
            Map<String, Object> map = new HashMap<String, Object>();
            map.put("key1","神马都是浮云");
            map.put("key2","heheda");
            list.add(map);
        }
        sa = new SimpleAdapter(this, list,R.layout.item_lv, new String[]{"key1","key2"},new int[]{R.id.tv,R.id.tv2});
        lv.setAdapter(sa);
    }
}