Android--listview下拉刷新，上拉加载

ListView的下拉刷新+上拉加载

1、XListView

git地址：https://github.com/Maxwin-z/XListView-Android

注意：

1、已停止维护，不推荐，推荐 android-pulltorefresh

2、XListView因为添加了Header，会导致存储的数据+1，所以赋值时需要position-1。补充：当去掉HeaderView时，position不用-1。

3、提个建议：上拉加载更多，最好在onCreate()中就执行setAdapter，然后不论是空数据、还是有数据，只用更新适配器就行了。

2、android-pulltorefresh

一个强大的拉动刷新开源项目， 支持各种控件下拉刷新 ，ListView、ViewPager、WebView、ExpandableListView、GridView、ScrollView、Horizontal ScrollView、Fragment上下左右拉动刷新，比下面johannilsson那个只支持ListView的强大的多。并且它实现的下拉刷新ListView在item不足一屏情况下也不会显示刷新提示，体验更好。
项目地址： https://github.com/chrisbanes/Android-PullToRefresh
Demo地址： https://github.com/Trinea/TrineaDownload/blob/master/pull-to-refreshview-demo.apk?raw=true

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笔记： 

ListView 下拉刷新功能

视频：http://www.imooc.com/learn/135

ListView 下拉刷新实现方式分析：

1、需要添加顶部下拉加载界面

2、需要监听onScrollListener，来判断当前是否显示在listview的最顶部

3、由于顶部下拉加载界面是跟随手势滑动状态来不断改变界面显示及功能的，所以需要监听onTouch事件，来改变当前状态及界面显示；

4、根据当前的状态加载数据

ListView 下拉刷新实现代码步骤

1：添加下拉加载界面，即ListView 的header头布局

2：监听ListView滚动事件，即onScrollListener()事件

3：监听ListView 的onTouch()事件

4：家在数据方法

主要代码：

ReFlashListView

package com.imooc.listviewfrashdemo1;

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

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;

import com.example.listviewfrashdemo1.R;

public class ReFlashListView extends ListView implements OnScrollListener {
	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；
	int scrollState;// listview 当前滚动状态；
	boolean isRemark;// 标记，当前是在listview最顶端摁下的；
	int startY;// 摁下时的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;// 刷新状态；
	IReflashListener iReflashListener;// 刷新数据的接口

	public ReFlashListView(Context context) {
		super(context);
		initView(context);
	}

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

	public ReFlashListView(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);
		initView(context);
	}

	/**
	 * 初始化界面，添加顶部布局文件到 listview
	 * 
	 * @param context
	 */
	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，header占用的宽，高；
	 * 
	 * @param view
	 */
	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 上边距；
	 * 
	 * @param topPadding
	 */
	private void topPadding(int topPadding) {
		header.setPadding(header.getPaddingLeft(), topPadding,
				header.getPaddingRight(), header.getPaddingBottom());
		header.invalidate();
	}

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

	@Override
	public void onScrollStateChanged(AbsListView view, int scrollState) {
		this.scrollState = scrollState;
	}

	@Override
	public boolean onTouchEvent(MotionEvent ev) {
		switch (ev.getAction()) {
		case MotionEvent.ACTION_DOWN:
			if (firstVisibleItem == 0) {
				isRemark = true;
				startY = (int) ev.getY();
			}
			break;

		case MotionEvent.ACTION_MOVE:
			onMove(ev);
			break;
		case MotionEvent.ACTION_UP:
			if (state == RELESE) {
				state = REFLASHING;
				// 加载最新数据；
				reflashViewByState();
				iReflashListener.onReflash();
			} else if (state == PULL) {
				state = NONE;
				isRemark = false;
				reflashViewByState();
			}
			break;
		}
		return super.onTouchEvent(ev);
	}

	/**
	 * 判断移动过程操作；
	 * 
	 * @param ev
	 */
	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 (space < headerHeight + 30) {
				state = PULL;
				reflashViewByState();
			} else if (space <= 0) {
				state = NONE;
				isRemark = false;
				reflashViewByState();
			}
			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
	 * 
	 * @author Administrator
	 */
	public interface IReflashListener {
		public void onReflash();
	}
}

MainActivity

	listview = (ReFlashListView) findViewById(R.id.listview);
	listview.setInterface(this);
	adapter = new MyAdapter(this, apk_list);
	listview.setAdapter(adapter);
	
	
	@Override
	public void onReflash() {
		Handler handler = new Handler();
		handler.postDelayed(new Runnable() {
			@Override
			public void run() {
				//获取最新数据
				setReflashData();
				//通知界面显示
				showList(apk_list);
				//通知listview 刷新数据完毕；
				listview.reflashComplete();
			}
		}, 2000);
	}