ListView下拉刷新功能的简单实现（慕课网视频总结 ，已测试实现）

ListView的下拉刷新功能应该是现在应用最广泛的功能了，手机屏幕毕竟有限，不能同一时间加载所有数据，需要我们及时刷新，而现在下拉刷新功能的实现就会解决这个问题，因此，本博文就ListView的下拉刷新功能的具体实现展开叙述，也将自己已经真机测试通过的代码奉上，当然还有截图啦~~~
我的代码是建立在上篇博文已经实现的ListView的适配基础上进行修改的，注释都有，需要的直接拿走，下边直接上代码啦~~~
MainActivity.java:

    package com.example.listviewpushtorefresh;

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

import com.example.listviewpushtorefresh.RefreshListView.IReflashListener;

import bean.Person;
import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.widget.ListView;

public class MainActivity extends Activity implements IReflashListener {

    private RefreshListView listview;
    MyAdapter adapter;
    List list= new ArrayList();
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        listview = (RefreshListView) findViewById(R.id.listview);
        listview.setInterface(this);
        adapter = new MyAdapter(MainActivity.this,0,getData());
        listview.setAdapter(adapter);
    }
    private List getData() {
        // TODO Auto-generated method stub

        for(int i=0;i<20;i++)
        {
            Person p = new Person(R.drawable.ic_launcher,i+"","我是第"+i+"项");
            list.add(p);
        }
        return list;
    }

    private List getReflashData() {
        // TODO Auto-generated method stub
//      List list= new ArrayList();
        for(int i=0;i<2;i++)
        {
            Person p = new Person(R.drawable.ic_launcher,i+"","我是第"+i+"项刷新数据");
            list.add(i,p);
        }
        return list;
    }

    @Override
    public void onReflash() {
        // TODO Auto-generated method stub
        Handler handler = new Handler();
        handler.postDelayed(new Runnable(){

            @Override
            public void run() {
                // TODO Auto-generated method stub
                //获取最新数据
                getReflashData();
                //通知界面显示
                showList(getReflashData());
                //通知listview刷新数据完毕
                listview.reflashComplete();

            }}, 2000);


    }

   private void showList(List objects){
       if(adapter == null){
           listview.setInterface(this);
           adapter=new MyAdapter(MainActivity.this,0,getReflashData());
           listview.setAdapter(adapter);

       }else{
           adapter.onDateChanger(getReflashData());
       }
   }


}

自定义的RefreshListView，继承于ListView,RefreshListView.java：

package com.example.listviewpushtorefresh;

import java.text.SimpleDateFormat;
import java.util.Date;

import android.annotation.SuppressLint;
import android.content.Context;
import android.util.AttributeSet;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.view.animation.RotateAnimation;
import android.widget.AbsListView;
import android.widget.AbsListView.OnScrollListener;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.ProgressBar;
import android.widget.TextView;

/**   
*    
* 项目名称：ListViewPushToRefresh   
* 类名称：RefreshListView   
* 类描述：   
* 创建人：dell   
* 创建时间：2016年3月3日 下午8:37:56   
* 修改人：dell   
* 修改时间：2016年3月3日 下午8:37:56   
* 修改备注：   
* @version    
*    
*/
public class RefreshListView extends ListView implements OnScrollListener{
    private static final int REFRESHING = 0;
    View header;//顶部布局文件
    int headerHeight;//顶部布局文件的高度
    int firstVisibleItem;//当前第一个可见的item的位置
    boolean isRemark;//标记，当前是在listview的最顶端摁下的
    int startY;//摁下是的Y值
    int state;//当前的状态
    final int NONE=0;//正常状态
    final int PULL=1;//提示下拉状态
    final int RELESE=2;//提示释放状态
    final int REFLASHING=3;//正在刷新状态
    int scrollState;
    IReflashListener iReflashListener;//刷新数据的接口

    //自定义view，要重写所有的构造方法
    public RefreshListView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        initView(context);
    }

    @SuppressLint("NewApi")
    public RefreshListView(Context context, AttributeSet attrs,
            int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
        initView(context);
    }

    public RefreshListView(Context context, AttributeSet attrs) {
        super(context, attrs);
        initView(context);
    }

    public RefreshListView(Context context) {
        super(context);
        initView(context);
    }
    /*
     * 初始化界面，添加顶部布局文件到listview
     */
    @SuppressLint("InflateParams")
    private void initView(Context context){
        LayoutInflater inflater = LayoutInflater.from(context);
        header = inflater.inflate(R.layout.header_layout, null);
        measureView(header);
        headerHeight =header.getMeasuredHeight();
        Log.i("tag", "headerHeight="+headerHeight);
        topPadding(-headerHeight);
        this.addHeaderView(header);

        this.setOnScrollListener(this);

    }
    //通知父布局占有多大地
    private void measureView(View view){
        ViewGroup.LayoutParams p = view.getLayoutParams();
        if(p==null)
        {
            p =  new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT);
        }
        int width = ViewGroup.getChildMeasureSpec(0, 0, p.width);
        int height;
        int tempHeight = p.height;
        if(tempHeight>0)
        {
            height = MeasureSpec.makeMeasureSpec(tempHeight,MeasureSpec.EXACTLY);
        }
        else
        {
            height = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
        }

        view.measure(width, height);
    }

    /*
     * 设置header布局的上边距
     */
    private void topPadding(int topPadding){
        header.setPadding(header.getPaddingLeft(), topPadding, header.getPaddingRight(), header.getPaddingBottom());

    }

    @Override
    public void onScrollStateChanged(AbsListView view, int scrollState) {
        // TODO Auto-generated method stub
        this.scrollState = scrollState;

    }

    @Override
    public void onScroll(AbsListView view, int firstVisibleItem,
            int visibleItemCount, int totalItemCount) {
        this.firstVisibleItem=firstVisibleItem;

    }

    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        // TODO Auto-generated method stub
        switch(ev.getAction()){
        case MotionEvent.ACTION_DOWN:
            if(firstVisibleItem==0){
                isRemark = true;
                startY = (int) ev.getY();
            }
            break;
        case MotionEvent.ACTION_UP:
            if(state==RELESE){
                state=REFLASHING;
                reflashViewByState();
                //加载最新数据
                iReflashListener.onReflash();


            }
            else if(state==PULL){
                state=NONE;
                isRemark = false;
                reflashViewByState();
            }
            break;
        case MotionEvent.ACTION_MOVE:
            onMove(ev);
            break;

        }



        return super.onTouchEvent(ev);
    }
    /*
     * 判断移动过程中的操作
     */
    private void onMove(MotionEvent ev){
        if(!isRemark){
            return;
        }
        int tempY = (int) ev.getY();
        int space = tempY-startY;
        int topPadding= space-headerHeight;

        switch(state){
        case NONE:
            if(space>0)
            {
                state = PULL;
                reflashViewByState();
            }
            break;
        case PULL:
            topPadding(topPadding);
            if(space>headerHeight+30 && scrollState==SCROLL_STATE_TOUCH_SCROLL){
                state = RELESE;
                reflashViewByState();
            }
            break;
        case RELESE:
            topPadding(topPadding);
            if(space30 ){
                state = PULL;
                reflashViewByState();
            }else if(space<=0){
                state = NONE;
                reflashViewByState();
                isRemark = false;
            }
            break;
        case REFLASHING:
            break;
        }


    }

    /**
     * 根据当前状态改变界面显示
     */
    private void reflashViewByState() {
        TextView tip = (TextView) header.findViewById(R.id.tip);
        ImageView arrow = (ImageView) header.findViewById(R.id.arrow);
        ProgressBar progress = (ProgressBar) header.findViewById(R.id.progress);

        RotateAnimation anim = new RotateAnimation(0,180, RotateAnimation.RELATIVE_TO_SELF,0.5f,RotateAnimation.RELATIVE_TO_SELF,0.5f);
        anim.setDuration(500);
        anim.setFillAfter(true);
        RotateAnimation anim1 = new RotateAnimation(180,0, RotateAnimation.RELATIVE_TO_SELF,0.5f,RotateAnimation.RELATIVE_TO_SELF,0.5f);
        anim1.setDuration(500);
        anim1.setFillAfter(true);

        switch(state){
        case NONE:
            arrow.clearAnimation();
            topPadding(-headerHeight);
            break;
        case PULL:
            arrow.setVisibility(View.VISIBLE);
            progress.setVisibility(View.GONE);
            tip.setText("下拉可以刷新");
            arrow.clearAnimation();
            arrow.setAnimation(anim1);
            break;
        case RELESE:
            arrow.setVisibility(View.VISIBLE);
            progress.setVisibility(View.GONE);
            tip.setText("松开可以刷新");
            arrow.clearAnimation();
            arrow.setAnimation(anim);
            break;
        case REFLASHING:
            topPadding(50);
            arrow.setVisibility(View.GONE);
            progress.setVisibility(View.VISIBLE);
            tip.setText("正在刷新");
            arrow.clearAnimation();
            break;
        }

    }
    /**
     * 获取完数据
     */
    public void reflashComplete(){
        state = NONE;
        isRemark = false;
        reflashViewByState();
        TextView lastupdatetime = (TextView) header.findViewById(R.id.lastupdate_time);
        SimpleDateFormat format = new SimpleDateFormat("yyyy年MM月dd日 hh:mm:ss");
        Date date = new Date(System.currentTimeMillis());
        String time = format.format(date);
        lastupdatetime.setText(time);
    }


    public void setInterface(IReflashListener iReflashListener){
        this.iReflashListener = iReflashListener;

    }




    /**
     * 
    *    
    * 刷新数据接口   
    * @version    
    *
     */
    public interface IReflashListener{
        public void onReflash();
    }


}

下拉刷新出来的头部文件header_layout.xml:

 
    <RelativeLayout  
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal">


        <LinearLayout
            android:id="@+id/layout"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentTop="true"
            android:layout_centerHorizontal="true"
            android:orientation="vertical" >

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

            <TextView
                android:id="@+id/lastupdate_time"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="n分钟前更新" />
        LinearLayout>

        <ImageView
            android:id="@+id/arrow"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentTop="true"
            android:layout_toLeftOf="@+id/layout"
            android:src="@drawable/arrow" />

        <ProgressBar
            android:id="@+id/progress"
            style="?android:attr/progressBarStyleSmall"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerVertical="true"
            android:layout_toLeftOf="@+id/arrow"
            android:visibility="gone" />

    RelativeLayout>

主布局文件activity_main.xml：

"http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

  <com.example.listviewpushtorefresh.RefreshListView 
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:id="@+id/listview"
      android:layout_margin="2dp"
      android:divider="#fafad2"
      android:dividerHeight="1dp"
      >

  com.example.listviewpushtorefresh.RefreshListView>

自定义适配器MyAdapter.java:

package com.example.listviewpushtorefresh;

import java.util.List;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.TextView;
import bean.Person;

public class MyAdapter extends ArrayAdapter {

    private int resoureId;
    private List objects;
    private Context context;


    public MyAdapter(Context context, int resourceId, List objects) {
        super(context, resourceId, objects);
        // TODO Auto-generated constructor stub
        this.objects=objects;
        this.context=context;

    }

    private static class ViewHolder
    {
        ImageView imageView;
        TextView title;
        TextView content;


    }

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

    @Override
    public Person getItem(int position) {
        // TODO Auto-generated method stub
        return objects.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) {
        // TODO Auto-generated method stub
        ViewHolder viewHolder = null;
        if(convertView==null)
        {
            viewHolder=new ViewHolder();
            LayoutInflater mInflater=LayoutInflater.from(context);
            convertView = mInflater.inflate(R.layout.item, null);
            viewHolder.imageView = (ImageView) convertView.findViewById(R.id.imageview);
            viewHolder.title = (TextView) convertView.findViewById(R.id.title);
            viewHolder.content = (TextView) convertView.findViewById(R.id.content);
            convertView.setTag(viewHolder);
        }
        else
        {
            viewHolder = (ViewHolder) convertView.getTag();
        }
        Person person = objects.get(position);
        if(null!=person)
        {
            viewHolder.imageView.setBackgroundResource(person.getPicture());
            viewHolder.title.setText(person.getTitle());
            viewHolder.content.setText(person.getContent());
        }

        return convertView;
    }

    public void onDateChanger(List reflashData) {
        // TODO Auto-generated method stub
        this.objects=reflashData;
        this.notifyDataSetChanged();

    }

}

自定义的类Person.java：

package bean;

public class Person {
 private int mPicture;
 private String mTitle;
 private String mContent;
 public  Person(int picture,String title,String content){
     this.mPicture = picture;
     this.mTitle = title;
     this.mContent = content;
 }
public int getPicture() {
    return mPicture;
}
public void setmPicture(int mPicture) {
    this.mPicture = mPicture;
}
public String getTitle() {
    return mTitle;
}
public void setTitle(String mTitle) {
    this.mTitle = mTitle;
}
public String getContent() {
    return mContent;
}
public void setContent(String mContent) {
    this.mContent = mContent;
}


}

每个条目的布局文件item.xml：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#a4d3ee">
    <ImageView 
        android:id="@+id/imageview"
        android:layout_width="50dp"
        android:layout_height="wrap_content"
        android:background="@drawable/ic_launcher"
        />

         <TextView 
        android:id="@+id/title"
        android:layout_width="150dp"
        android:layout_height="wrap_content"
        android:text="title"
        android:textSize="20sp"
        android:layout_toRightOf="@+id/imageview"/>
    <TextView 
        android:id="@+id/content"
        android:layout_width="150dp"
        android:layout_height="wrap_content"
        android:text="content"
        android:layout_alignLeft="@+id/title"
        android:layout_below="@+id/title"/>


RelativeLayout>

下面上运行截图：
刷新前：

刷新后：

OK，至此所有代码结束了，代码可能有不完善的地方，还请路过的大神多多指教哇！！！

经检查发现，刷新数据时总会一次刷新三次，现在已经把bug修改好了，下面把修改过的部分再次附上，没有修改的都和上边一样：
修改过的MainActivity.java:

package com.example.listviewpushtorefresh;

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

import com.example.listviewpushtorefresh.RefreshListView.IReflashListener;

import bean.Person;
import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.widget.ListView;

public class MainActivity extends Activity implements IReflashListener {

    private RefreshListView listview;
    MyAdapter adapter;
    List list= new ArrayList();
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        listview = (RefreshListView) findViewById(R.id.listview);
        listview.setInterface(this);
        adapter = new MyAdapter(MainActivity.this,0,getData());
        listview.setAdapter(adapter);
    }
    private List getData() {
        // TODO Auto-generated method stub

        for(int i=0;i<20;i++)
        {
            Person p = new Person(R.drawable.ic_launcher,i+"","我是第"+i+"项");
            list.add(p);
        }
        return list;
    }

    private List getReflashData() {
        // TODO Auto-generated method stub
//      List list= new ArrayList();
        for(int i=0;i<2;i++)
        {
            Person p = new Person(R.drawable.ic_launcher,i+"","我是第"+i+"项刷新数据");
            list.add(i,p);
        }
        return list;
    }

    @Override
    public void onReflash() {
        // TODO Auto-generated method stub
        Handler handler = new Handler();
        handler.postDelayed(new Runnable(){

            @Override
            public void run() {
                // TODO Auto-generated method stub
                //获取最新数据
//              getReflashData();
                //通知界面显示
                showList(getReflashData());
                //通知listview刷新数据完毕
                listview.reflashComplete();

            }}, 2000);


    }

   private void showList(List objects){
       if(adapter == null){
           listview.setInterface(this);
           adapter=new MyAdapter(MainActivity.this,0,objects);
           listview.setAdapter(adapter);

       }else{
           adapter.onDateChanger(objects);
       }
   }


}