Android菜鸟之listview下拉刷新

《1》首先我们要写一个自定义的listview(写一个类继承ListView类)

public class RefreshListView extends ListView

然后我们需要填充这个RefreshListView 

class MyAdapter extends BaseAdapter {@Overridepublic int getCount() {return dataList.size();}@Overridepublic Object getItem(int position) {return null;}@Overridepublic long getItemId(int position) {return 0;}@Overridepublic View getView(int position, View convertView, ViewGroup parent) {TextView tv = new TextView(MainActivity.this);tv.setText(dataList.get(position));tv.setTextSize(18);return tv;}}

显示基本的数据列表

2》自定义RefreshListView 的头

/** * 初始化ListView的頭佈局 */private void initHeader() {headView=LayoutInflater.from(getContext()).inflate(R.layout.listview_header, null);ivArrow = (ImageView) headView.findViewById(R.id.iv_listview_header_arrow);//ivArrow.setMinimumWidth(70);tvState = (TextView) headView.findViewById(R.id.tv_listview_header_state);tvLastUpdateTime = (TextView) headView.findViewById(R.id.tv_listview_header_last_update_time);mProgressBar = (ProgressBar) headView.findViewById(R.id.pb_listview_header_arrow);headView.measure(0, 0);//测量头布局的宽和高headerViewHeight = headView.getMeasuredHeight();//布局的高度155Log.i(TAG,"头布局的高度："+headerViewHeight);headView.setPadding(0,-headerViewHeight,0,0);addHeaderView(headView);initAnimation();}

用到的listview_header.xml

<?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="wrap_content"    android:orientation="horizontal" >    <FrameLayout        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_margin="10dip" >        <ImageView            android:id="@+id/iv_listview_header_arrow"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:layout_gravity="center"            android:src="@drawable/common_listview_headview_red_arrow" />        <ProgressBar            android:id="@+id/pb_listview_header_arrow"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:layout_gravity="center"             android:visibility="gone"            android:indeterminateDrawable="@drawable/custom_prograssbar"/>    </FrameLayout>    <LinearLayout        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:layout_gravity="center_vertical"        android:gravity="center_horizontal"        android:orientation="vertical" >        <TextView             android:id="@+id/tv_listview_header_state"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:text="下來刷新"            android:textColor="#FF0000"            android:textSize="18sp" />        <TextView            android:id="@+id/tv_listview_header_last_update_time"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:text="最后刷新时间:1990-09-09 09:09:09"            android:textColor="@android:color/darker_gray"            android:textSize="14sp" />    </LinearLayout></LinearLayout>

接下来我们要理解下拉的逻辑：

1）首先我们需要隐藏listView的头

2）实现public boolean onTouchEvent(MotionEvent ev) {

@Overridepublic boolean onTouchEvent(MotionEvent ev) {switch (ev.getAction()) {case MotionEvent.ACTION_DOWN://下拉事件downY = (int)ev.getY();break;case MotionEvent.ACTION_MOVE:int moveY=(int) ev.getY();//移动中Y轴的偏移量//Log.i(TAG, "移動："+moveY);//Log.i(TAG,"下移動："+downY);int diffY=moveY-downY/3;//Log.i(TAG,"diffY:"+diffY);int paddingTop=-headerViewHeight+diffY;if(mfirstVisibleItem==0 && paddingTop>-headerViewHeight){//當前是在顶部if(paddingTop>0&¤tState==DOWN_REFRESH){//下拉刷新Log.i(TAG,"完全显示了，可以松开刷新了");currentState=RELEASE_REFRESH;//鬆開刷新refreshHeaderViewState();}else if(paddingTop<0&¤tState==RELEASE_REFRESH){//正在刷新中Log.i(TAG,"没有完全显示，当前是下拉刷新");currentState=DOWN_REFRESH;refreshHeaderViewState();}headView.setPadding(0,paddingTop, 0, 0);return true;}headView.setPadding(0,paddingTop, 0,0);break;case MotionEvent.ACTION_UP:if(currentState==DOWN_REFRESH){//下拉刷新抬起手指,需要把头布局隐藏headView.setPadding(0,-headerViewHeight, 0, 0);}else if(currentState==RELEASE_REFRESH){//释放刷新 ,显示正在刷新中的状态currentState=REFRESHING;//正在刷新中refreshHeaderViewState();//刷新头布局的状态/** * 去掉边距 */headView.setPadding(0, 0, 0, 0);if(mOnRefreshListener!=null){mOnRefreshListener.onDownRefresh();//刷新数据}//刷新完数据后 头隐藏}break;default:break;}return super.onTouchEvent(ev);}

3）计算滑动的距离，同时显示头

int paddingTop=-headerViewHeight+diffY;4）自定义动画修改箭头（两个箭头转动的动画）private void initAnimation() {        upAnimation = new RotateAnimation(0, -180                , Animation.RELATIVE_TO_SELF, 0.5f,                 Animation.RELATIVE_TO_SELF, 0.5f);        upAnimation.setDuration(500);        upAnimation.setFillAfter(true);//停留在动画结束时                downAnimation = new RotateAnimation(-180,-360                , Animation.RELATIVE_TO_SELF, 0.5f,                 Animation.RELATIVE_TO_SELF, 0.5f);        upAnimation.setDuration(500);        upAnimation.setFillAfter(true);//停留在动画结束时    }5）开始编写回调函数（判断头是否全部显示，然后加载数据，加载数据的同时修改图片为sing）public interface OnRefreshListener  {/** * 当下拉刷新时回调 */public void onDownRefresh();/** * 当加载更多时回调 */public void onLoadMoring();}主界面加载数据/** * 异步加载数据 */@Overridepublic void onLoadMoring() {//异步去抓取数据new AsyncTask<Void, Void, Void>(){@Overrideprotected Void doInBackground(Void... params) {SystemClock.sleep(2000);dataList.add("这是加载更多的数据1");dataList.add("这是加载更多的数据2");dataList.add("这是加载更多的数据3");return null;}@Overrideprotected void onPostExecute(Void result) {mAdapter.notifyDataSetChanged();mRefreshListView.hideFooterView();//隐藏脚布局super.onPostExecute(result);}}.execute(new Void[]{});}6）数据加载完毕，隐藏工作/** * 隐藏头布局 */public void hideHeaderView(){headView.setPadding(0, -headerViewHeight, 0, 0);mProgressBar.setVisibility(View.GONE);mProgressBar.clearAnimation();ivArrow.setVisibility(View.VISIBLE);tvState.setText("下来刷新");tvLastUpdateTime.setText("最后刷新时间:"+getLastUpdateTime());currentState=DOWN_REFRESH;}7）自定义监听/** * 设置刷新的监听事件 * 刷新完之后需要用hideHeaderView(),隐藏头buju * @param listener */public void setOnRefreshListener(OnRefreshListener listener){this.mOnRefreshListener=listener;}8）细节：/** * 当滚动状态改变时回调 * SCroll_state_idle 停止状态 * scroll_state_touch_scroll 触摸滚动（按住移动） * scroll_state_fing 滚动滑动 */@Overridepublic void onScrollStateChanged(AbsListView view, int scrollState) {if(scrollState==SCROLL_STATE_IDLE||scrollState==SCROLL_STATE_FLING){if(isScrollToBottom && !isLoadMoring){isLoadMoring=true;//加载更多中Log.i(TAG,"滑動到底部");footerView.setPadding(0, 0, 0, 0);//显示脚布局//滚动到底部,使用脚布局显示this.setSelection(this.getCount());//调用注册监听事件if(mOnRefreshListener!=null){mOnRefreshListener.onLoadMoring();}}}}/** * 当ListView滚动时回调方法 *  * @param firstVisibleItem *            当前屏幕第一个可见的item的索引 * @param visibleItemCount *            当前屏幕显示了多少个item的数量 * @param totalItemCount *            listView的总长度 */@Overridepublic void onScroll(AbsListView view, int firstVisibleItem,int visibleItemCount, int totalItemCount) {mfirstVisibleItem = firstVisibleItem;if ((firstVisibleItem + visibleItemCount) == (totalItemCount)) {// 判断是否滚动到底部//Log.i(TAG, "滚动到底部,滚动到底部,滚动到底部,滚动到底部");isScrollToBottom = true;} else {isScrollToBottom = false;}}源代码下载：http://download.csdn.net/detail/javamov/6948855