listview下拉刷新 上拉(滑动分页)加载更多

最 近做的类似于微博的项目中,有个Android功能要使用到listview的向下拉刷新来刷新最新消息,向上拉刷新(滑动分页)来加载更多。
新浪微博就是使用这种方式的典型。
当用户从网络上读取微博的时候,如果一下子全部加载用户未读的微博这将耗费比较长的时间,造成不好的用户体验,同时一屏的内容也不足以显示如此多的内容。这时候,我们就需要用到另一个功能,那就是listview的分页了,其实这个分页可以做成客户端的分页,也可以做成服务器端的分页(点击加载时,从服务器对应的加载第N页就好了!!!)。通过分页分次加载数据,用户看多少就去加载多少。
通常这也分为两种方式,一种是设置一个按钮,用户点击即加载。另一种是当用户滑动到底部时自动加载。今天我就和大家分享一下滑动到底端时自动加载这个功能的实现。
效果图如下所示:

下拉刷新最主要的流程是:
(1). 下拉,显示提示头部界面(HeaderView),这个过程提示用户”下拉刷新”
(2). 下拉到一定程度,超出了刷新最基本的下拉界限,我们认为达到了刷新的条件,提示用户可以”松手刷新”了,效果上允许用户继续下拉
(3). 用户松手,可能用户下拉远远不止提示头部界面,所以这一步,先反弹回仅显示提示头部界面,然后提示用户”正在加载”。
(4). 加载完成后,隐藏提示头部界面。

那么让我们看看怎么才能实现呢???
第一步:既然是要显示listview ,那么就应该有个listview 的容器pulldown.xml

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<?xml version="1.0" encoding="utf-8"?>
<com.solo.pulldown.PullDownView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/pull_down_view"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="@android:color/white">
</com.solo.pulldown.PullDownView>

第二步:自定义一个listview中显示的item对象pulldown_item.xml

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<?xml version="1.0" encoding="utf-8"?>
    android:id="@android:id/text1"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:gravity="center_vertical"
    android:paddingLeft="6dip"
    android:minHeight="?android:attr/listPreferredItemHeight"
    android:textColor="@android:color/black"
/>

第三步:定义一个header的xml布局文件pulldown_header.xml

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<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:paddingBottom="10dp"
    android:paddingTop="10dp" >
    <ImageView
        android:id="@+id/pulldown_header_arrow"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_marginLeft="20dp"
        android:scaleType="centerCrop"
        android:src="@drawable/z_arrow_down"
        android:visibility="invisible" />
    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBottom="@+id/pulldown_header_arrow"
        android:layout_alignTop="@+id/pulldown_header_arrow"
        android:layout_centerHorizontal="true"
        android:gravity="center_vertical"
        android:orientation="vertical" >
        <TextView
            android:id="@+id/pulldown_header_text"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal"
            android:text="加载中..." />
        <TextView
            android:id="@+id/pulldown_header_date"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal"
            android:text="更新于:"
            android:visibility="gone" />
    </LinearLayout>
    <ProgressBar
        android:id="@+id/pulldown_header_loading"
        style="@android:style/Widget.ProgressBar.Small.Inverse"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerVertical="true"
        android:layout_marginLeft="20dp" />
</RelativeLayout>

第四步:如果需要向上拉更新更多的话,那就定义一个底部的footer的布局文件,在此为方便起见,只定义一个progressbar跟textview,更加复杂的显示,就交给你们了~~~~~pulldown_footer.xml:

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<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:paddingBottom="10dp"
    android:paddingTop="10dp" >
    <TextView
        android:id="@+id/pulldown_footer_text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:text="更多"
        android:textSize="15dp" />
    <ProgressBar
        android:id="@+id/pulldown_footer_loading"
        style="@android:style/Widget.ProgressBar.Small.Inverse"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerVertical="true"
        android:layout_marginLeft="20dp"
        android:visibility="gone" />
</RelativeLayout>

第五步:那么主要的文件这才登场:::::::重写listview这个文件主要任务是提供触摸的事件的处理方法。

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/**
 * <p>一个可以监听ListView是否滚动到最顶部或最底部的自定义控件</p>
 * 只能监听由触摸产生的,如果是ListView本身Flying导致的,则不能监听</br>
 * 如果加以改进,可以实现监听scroll滚动的具体位置等
 */
public class ScrollOverListView extends ListView {
    private int mLastY;
    private int mTopPosition;
    private int mBottomPosition;
    public ScrollOverListView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        init();
    }
    public ScrollOverListView(Context context, AttributeSet attrs) {
        super(context, attrs);
        init();
    }
    public ScrollOverListView(Context context) {
        super(context);
        init();
    }
    private void init(){
        mTopPosition = 0;
        mBottomPosition = 0;
    }
    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        final int action = ev.getAction();
        final int y = (int) ev.getRawY();
        switch(action){
            case MotionEvent.ACTION_DOWN:{
                mLastY = y;
                final boolean isHandled = mOnScrollOverListener.onMotionDown(ev);
                if (isHandled) {
                    mLastY = y;
                    return isHandled;
                }
                break;
            }
            case MotionEvent.ACTION_MOVE:{
                final int childCount = getChildCount();
                if(childCount == 0) return super.onTouchEvent(ev);
                final int itemCount = getAdapter().getCount() - mBottomPosition;
                final int deltaY = y - mLastY;
                //DLog.d("lastY=%d y=%d", mLastY, y);
                final int firstTop = getChildAt(0).getTop();
                final int listPadding = getListPaddingTop();
                final int lastBottom = getChildAt(childCount - 1).getBottom();
                final int end = getHeight() - getPaddingBottom();
                final int firstVisiblePosition = getFirstVisiblePosition();
                final boolean isHandleMotionMove = mOnScrollOverListener.onMotionMove(ev, deltaY);
                if(isHandleMotionMove){
                    mLastY = y;
                    return true;
                }
                //DLog.d("firstVisiblePosition=%d firstTop=%d listPaddingTop=%d deltaY=%d", firstVisiblePosition, firstTop, listPadding, deltaY);
                if (firstVisiblePosition <= mTopPosition && firstTop >= listPadding && deltaY > 0) {
                    final boolean isHandleOnListViewTopAndPullDown;
                    isHandleOnListViewTopAndPullDown = mOnScrollOverListener.onListViewTopAndPullDown(deltaY);
                    if(isHandleOnListViewTopAndPullDown){
                        mLastY = y;
                        return true;
                    }
                }
                // DLog.d("lastBottom=%d end=%d deltaY=%d", lastBottom, end, deltaY);
                if (firstVisiblePosition + childCount >= itemCount && lastBottom <= end && deltaY < 0) {
                    final boolean isHandleOnListViewBottomAndPullDown;
                    isHandleOnListViewBottomAndPullDown = mOnScrollOverListener.onListViewBottomAndPullUp(deltaY);
                    if(isHandleOnListViewBottomAndPullDown){
                        mLastY = y;
                        return true;
                    }
                }
                break;
            }
            case MotionEvent.ACTION_UP:{
                final boolean isHandlerMotionUp = mOnScrollOverListener.onMotionUp(ev);
                if (isHandlerMotionUp) {
                    mLastY = y;
                    return true;
                }
                break;
            }
        }
        mLastY = y;
        return super.onTouchEvent(ev);
    }
    /**空的*/
    private OnScrollOverListener mOnScrollOverListener = new OnScrollOverListener(){
        @Override
        public boolean onListViewTopAndPullDown(int delta) {
            return false;
        }
        @Override
        public boolean onListViewBottomAndPullUp(int delta) {
            return false;
        }
        @Override
        public boolean onMotionDown(MotionEvent ev) {
            return false;
        }
        @Override
        public boolean onMotionMove(MotionEvent ev, int delta) {
            return false;
        }
        @Override
        public boolean onMotionUp(MotionEvent ev) {
            return false;
        }
    };
    // =============================== public method ===============================
    /**
     * 可以自定义其中一个条目为头部,头部触发的事件将以这个为准,默认为第一个
     *
     * @param index 正数第几个,必须在条目数范围之内
     */
    public void setTopPosition(int index){
        if(getAdapter() == null)
            throw new NullPointerException("You must set adapter before setTopPosition!");
        if(index < 0)
            throw new IllegalArgumentException("Top position must > 0");
        mTopPosition = index;
    }
    /**
     * 可以自定义其中一个条目为尾部,尾部触发的事件将以这个为准,默认为最后一个
     *
     * @param index 倒数第几个,必须在条目数范围之内
     */
    public void setBottomPosition(int index){
        if(getAdapter() == null)
            throw new NullPointerException("You must set adapter before setBottonPosition!");
        if(index < 0)
            throw new IllegalArgumentException("Bottom position must > 0");
        mBottomPosition = index;
    }
    /**
     * 设置这个Listener可以监听是否到达顶端,或者是否到达低端等事件</br>
     *
     * @see OnScrollOverListener
     */
    public void setOnScrollOverListener(OnScrollOverListener onScrollOverListener){
        mOnScrollOverListener = onScrollOverListener;
    }
    /**
     * 滚动监听接口</br>
     * @see ScrollOverListView#setOnScrollOverListener(OnScrollOverListener)
     *
     */
    public interface OnScrollOverListener {
        /**
         * 到达最顶部触发
         *
         * @param delta 手指点击移动产生的偏移量
         * @return
         */
        boolean onListViewTopAndPullDown(int delta);
        /**
         * 到达最底部触发
         *
         * @param delta 手指点击移动产生的偏移量
         * @return
         */
        boolean onListViewBottomAndPullUp(int delta);
        /**
         * 手指触摸按下触发,相当于{@link MotionEvent#ACTION_DOWN}
         *
         * @return 返回true表示自己处理
         * @see View#onTouchEvent(MotionEvent)
         */
        boolean onMotionDown(MotionEvent ev);
        /**
         * 手指触摸移动触发,相当于{@link MotionEvent#ACTION_MOVE}
         *
         * @return 返回true表示自己处理
         * @see View#onTouchEvent(MotionEvent)
         */
        boolean onMotionMove(MotionEvent ev, int delta);
        /**
         * 手指触摸后提起触发,相当于{@link MotionEvent#ACTION_UP}
         *
         * @return 返回true表示自己处理
         * @see View#onTouchEvent(MotionEvent)
         */
        boolean onMotionUp(MotionEvent ev);
    }
}

第六步:下拉刷新控件,真正实现下拉刷新的是这个控件,而上面的那个ScrollOverListView只是提供触摸的事件等

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/**
 * 下拉刷新控件</br>
 * 真正实现下拉刷新的是这个控件,
 * ScrollOverListView只是提供触摸的事件等
 */
public class PullDownView extends LinearLayout implements OnScrollOverListener{
    private static final String TAG = "PullDownView";
    private static final int START_PULL_DEVIATION = 50; // 移动误差
    private static final int AUTO_INCREMENTAL = 10;     // 自增量,用于回弹
    private static final int WHAT_DID_LOAD_DATA = 1;    // Handler what 数据加载完毕
    private static final int WHAT_ON_REFRESH = 2;       // Handler what 刷新中
    private static final int WHAT_DID_REFRESH = 3;      // Handler what 已经刷新完
    private static final int WHAT_SET_HEADER_HEIGHT = 4;// Handler what 设置高度
    private static final int WHAT_DID_MORE = 5;         // Handler what 已经获取完更多
    private static final int DEFAULT_HEADER_VIEW_HEIGHT = 105// 头部文件原本的高度
    private static SimpleDateFormat dateFormat = new SimpleDateFormat("MM-dd HH:mm");
    private View mHeaderView;
    private LayoutParams mHeaderViewParams;
    private TextView mHeaderViewDateView;
    private TextView mHeaderTextView;
    private ImageView mHeaderArrowView;
    private View mHeaderLoadingView;
    private View mFooterView;
    private TextView mFooterTextView;
    private View mFooterLoadingView;
    private ScrollOverListView mListView;
    private OnPullDownListener mOnPullDownListener;
    private RotateAnimation mRotateOTo180Animation;
    private RotateAnimation mRotate180To0Animation;
    private int mHeaderIncremental; // 增量
    private float mMotionDownLastY; // 按下时候的Y轴坐标
    private boolean mIsDown;            // 是否按下
    private boolean mIsRefreshing;      // 是否下拉刷新中
    private boolean mIsFetchMoreing;    // 是否获取更多中
    private boolean mIsPullUpDone;      // 是否回推完成
    private boolean mEnableAutoFetchMore;   // 是否允许自动获取更多
    // 头部文件的状态
    private static final int HEADER_VIEW_STATE_IDLE = 0;            // 空闲
    private static final int HEADER_VIEW_STATE_NOT_OVER_HEIGHT = 1; // 没有超过默认高度
    private static final int HEADER_VIEW_STATE_OVER_HEIGHT = 2;     // 超过默认高度
    private int mHeaderViewState = HEADER_VIEW_STATE_IDLE;
    public PullDownView(Context context, AttributeSet attrs) {
        super(context, attrs);
        initHeaderViewAndFooterViewAndListView(context);
    }
    public PullDownView(Context context) {
        super(context);
        initHeaderViewAndFooterViewAndListView(context);
    }
    /*
     * ==================================
     * Public method
     * 外部使用,具体就是用这几个就可以了
     *
     * ==================================
     */
    /**
     * 刷新事件接口
     */
    public interface OnPullDownListener {
        void onRefresh();
        void onMore();
    }
    /**
     * 通知加载完了数据,要放在Adapter.notifyDataSetChanged后面
     * 当你加载完数据的时候,调用这个notifyDidLoad()
     * 才会隐藏头部,并初始化数据等
     */
    public void notifyDidLoad() {
        mUIHandler.sendEmptyMessage(WHAT_DID_LOAD_DATA);
    }
    /**
     * 通知已经刷新完了,要放在Adapter.notifyDataSetChanged后面
     * 当你执行完刷新任务之后,调用这个notifyDidRefresh()
     * 才会隐藏掉头部文件等操作
     */
    public void notifyDidRefresh() {
        mUIHandler.sendEmptyMessage(WHAT_DID_REFRESH);
    }
    /**
     * 通知已经获取完更多了,要放在Adapter.notifyDataSetChanged后面
     * 当你执行完更多任务之后,调用这个notyfyDidMore()
     * 才会隐藏加载圈等操作
     */
    public void notifyDidMore() {
        mUIHandler.sendEmptyMessage(WHAT_DID_MORE);
    }
    /**
     * 设置监听器
     * @param listener
     */
    public void setOnPullDownListener(OnPullDownListener listener){
        mOnPullDownListener = listener;
    }
    /**
     * 获取内嵌的listview
     * @return ScrollOverListView
     */
    public ListView getListView(){
        return mListView;
    }
    /**
     * 是否开启自动获取更多
     * 自动获取更多,将会隐藏footer,并在到达底部的时候自动刷新
     * @param index 倒数第几个触发
     */
    public void enableAutoFetchMore(boolean enable, int index){
        if(enable){
            mListView.setBottomPosition(index);
            mFooterLoadingView.setVisibility(View.VISIBLE);
        }else{
            mFooterTextView.setText("更多");
            mFooterLoadingView.setVisibility(View.GONE);
        }
        mEnableAutoFetchMore = enable;
    }
    /*
     * ==================================
     * Private method
     * 具体实现下拉刷新等操作
     *
     * ==================================
     */
    /**
     * 初始化界面
     */
    private void initHeaderViewAndFooterViewAndListView(Context context){
        setOrientation(LinearLayout.VERTICAL);
        //setDrawingCacheEnabled(false);
        /*
         * 自定义头部文件
         * 放在这里是因为考虑到很多界面都需要使用
         * 如果要修改,和它相关的设置都要更改
         */
        mHeaderView = LayoutInflater.from(context).inflate(R.layout.pulldown_header, null);
        mHeaderViewParams = new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT);
        addView(mHeaderView, 0, mHeaderViewParams);
        mHeaderTextView = (TextView) mHeaderView.findViewById(R.id.pulldown_header_text);
        mHeaderArrowView = (ImageView) mHeaderView.findViewById(R.id.pulldown_header_arrow);
        mHeaderLoadingView = mHeaderView.findViewById(R.id.pulldown_header_loading);
        // 注意,图片旋转之后,再执行旋转,坐标会重新开始计算
        mRotateOTo180Animation = new RotateAnimation(0, 180,
                Animation.RELATIVE_TO_SELF, 0.5f,
                Animation.RELATIVE_TO_SELF, 0.5f);
        mRotateOTo180Animation.setDuration(250);
        mRotateOTo180Animation.setFillAfter(true);
        mRotate180To0Animation = new RotateAnimation(180, 0,
                Animation.RELATIVE_TO_SELF, 0.5f,
                Animation.RELATIVE_TO_SELF, 0.5f);
        mRotate180To0Animation.setDuration(250);
        mRotate180To0Animation.setFillAfter(true);
        /**
         * 自定义脚部文件
         */
        mFooterView = LayoutInflater.from(context).inflate(R.layout.pulldown_footer, null);
        mFooterTextView = (TextView) mFooterView.findViewById(R.id.pulldown_footer_text);
        mFooterLoadingView = mFooterView.findViewById(R.id.pulldown_footer_loading);
        mFooterView.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                if(!mIsFetchMoreing){
                    mIsFetchMoreing = true;
                    mFooterLoadingView.setVisibility(View.VISIBLE);
                    mOnPullDownListener.onMore();
                }
            }
        });
        /*
         * ScrollOverListView 同样是考虑到都是使用,所以放在这里
         * 同时因为,需要它的监听事件
         */
        mListView = new ScrollOverListView(context);
        mListView.setOnScrollOverListener(this);
        mListView.setCacheColorHint(0);
        addView(mListView, LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT);
        // 空的listener
        mOnPullDownListener = new OnPullDownListener() {
            @Override
            public void onRefresh() {}
            @Override
            public void onMore() {}
        };
    }
    /**
     * 在下拉和回推的时候检查头部文件的状态</br>
     * 如果超过了默认高度,就显示松开可以刷新,
     * 否则显示下拉可以刷新
     */
    private void checkHeaderViewState(){
        if(mHeaderViewParams.height >= DEFAULT_HEADER_VIEW_HEIGHT){
            if(mHeaderViewState == HEADER_VIEW_STATE_OVER_HEIGHT) return;
            mHeaderViewState = HEADER_VIEW_STATE_OVER_HEIGHT;
            mHeaderTextView.setText("松开可以刷新");
            mHeaderArrowView.startAnimation(mRotateOTo180Animation);
        }else{
            if(mHeaderViewState == HEADER_VIEW_STATE_NOT_OVER_HEIGHT
                    || mHeaderViewState == HEADER_VIEW_STATE_IDLE) return;
            mHeaderViewState = HEADER_VIEW_STATE_NOT_OVER_HEIGHT;
            mHeaderTextView.setText("下拉可以刷新");
            mHeaderArrowView.startAnimation(mRotate180To0Animation);
        }
    }
    private void setHeaderHeight(final int height){
        mHeaderIncremental = height;
        mHeaderViewParams.height = height;
        mHeaderView.setLayoutParams(mHeaderViewParams);
    }
    /**
     * 自动隐藏动画
     */
    class HideHeaderViewTask extends TimerTask{
        @Override
        public void run() {
            if(mIsDown) {
                cancel();
                return;
            }
            mHeaderIncremental -= AUTO_INCREMENTAL;
            if(mHeaderIncremental > 0){
                mUIHandler.sendEmptyMessage(WHAT_SET_HEADER_HEIGHT);
            }else{
                mHeaderIncremental = 0;
                mUIHandler.sendEmptyMessage(WHAT_SET_HEADER_HEIGHT);
                cancel();
            }
        }
    }
    /**
     * 自动显示动画
     */
    class ShowHeaderViewTask extends TimerTask{
        @Override
        public void run() {
            if(mIsDown) {
                cancel();
                return;
            }
            mHeaderIncremental -= AUTO_INCREMENTAL;
            if(mHeaderIncremental > DEFAULT_HEADER_VIEW_HEIGHT){
                mUIHandler.sendEmptyMessage(WHAT_SET_HEADER_HEIGHT);
            }else{
                mHeaderIncremental = DEFAULT_HEADER_VIEW_HEIGHT;
                mUIHandler.sendEmptyMessage(WHAT_SET_HEADER_HEIGHT);
                if(!mIsRefreshing){
                    mIsRefreshing = true;
                    mUIHandler.sendEmptyMessage(WHAT_ON_REFRESH);
                }
                cancel();
            }
        }
    }
    private Handler mUIHandler = new Handler(){
        @Override
        public void handleMessage(Message msg) {
            switch (msg.what) {
                case WHAT_DID_LOAD_DATA:{
                    mHeaderViewParams.height = 0;
                    mHeaderLoadingView.setVisibility(View.GONE);
                    mHeaderTextView.setText("下拉可以刷新");
                    mHeaderViewDateView = (TextView) mHeaderView.findViewById(R.id.pulldown_header_date);
                    mHeaderViewDateView.setVisibility(View.VISIBLE);
                    mHeaderViewDateView.setText("更新于:" + dateFormat.format(new Date(System.currentTimeMillis())));
                    mHeaderArrowView.setVisibility(View.VISIBLE);
                    showFooterView();
                    return;
                }
                case WHAT_ON_REFRESH:{
                    // 要清除掉动画,否则无法隐藏
                    mHeaderArrowView.clearAnimation();
                    mHeaderArrowView.setVisibility(View.INVISIBLE);
                    mHeaderLoadingView.setVisibility(View.VISIBLE);
                    mOnPullDownListener.onRefresh();
                    return;
                }
                case WHAT_DID_REFRESH :{
                    mIsRefreshing = false;
                    mHeaderViewState = HEADER_VIEW_STATE_IDLE;
                    mHeaderArrowView.setVisibility(View.VISIBLE);
                    mHeaderLoadingView.setVisibility(View.GONE);
                    mHeaderViewDateView.setText("更新于:" + dateFormat.format(new Date(System.currentTimeMillis())));
                    setHeaderHeight(0);
                    showFooterView();
                    return;
                }
                case WHAT_SET_HEADER_HEIGHT :{
                    setHeaderHeight(mHeaderIncremental);
                    return;
                }
                case WHAT_DID_MORE :{
                    mIsFetchMoreing = false;
                    mFooterTextView.setText("更多");
                    mFooterLoadingView.setVisibility(View.GONE);
                }
            }
        }
    };
    /**
     * 显示脚步脚部文件
     */
    private void showFooterView(){
        if(mListView.getFooterViewsCount() == 0 && isFillScreenItem()){
            mListView.addFooterView(mFooterView);
            mListView.setAdapter(mListView.getAdapter());
        }
    }
    /**
     * 条目是否填满整个屏幕
     */
    private boolean isFillScreenItem(){
        final int firstVisiblePosition = mListView.getFirstVisiblePosition();
        final int lastVisiblePostion = mListView.getLastVisiblePosition() - mListView.getFooterViewsCount();
        final int visibleItemCount = lastVisiblePostion - firstVisiblePosition + 1;
        final int totalItemCount = mListView.getCount() - mListView.getFooterViewsCount();
        if(visibleItemCount < totalItemCount) return true;
        return false;
    }
    /*
     * ==================================
     * 实现 OnScrollOverListener接口
     *
     *
     * ==================================
     */
    @Override
    public boolean onListViewTopAndPullDown(int delta) {
        if(mIsRefreshing || mListView.getCount() - mListView.getFooterViewsCount() == 0) return false;
        int absDelta = Math.abs(delta);
        final int i = (int) Math.ceil((double)absDelta / 2);
        mHeaderIncremental += i;
        if(mHeaderIncremental >= 0){ // && mIncremental <= mMaxHeight
            setHeaderHeight(mHeaderIncremental);
            checkHeaderViewState();
        }
        return true;
    }
    @Override
    public boolean onListViewBottomAndPullUp(int delta) {
        if(!mEnableAutoFetchMore || mIsFetchMoreing) return false;
        // 数量充满屏幕才触发
        if(isFillScreenItem()){
            mIsFetchMoreing = true;
            mFooterTextView.setText("加载更多中...");
            mFooterLoadingView.setVisibility(View.VISIBLE);
            mOnPullDownListener.onMore();
            return true;
        }
        return false;
    }
    @Override
    public boolean onMotionDown(MotionEvent ev) {
        mIsDown = true;
        mIsPullUpDone = false;
        mMotionDownLastY = ev.getRawY();
        return false;
    }
    @Override
    public boolean onMotionMove(MotionEvent ev, int delta) {
        //当头部文件回推消失的时候,不允许滚动
        if(mIsPullUpDone) return true;
        // 如果开始按下到滑动距离不超过误差值,则不滑动
        final int absMotionY = (int) Math.abs(ev.getRawY() - mMotionDownLastY);
        if(absMotionY < START_PULL_DEVIATION) return true;
        final int absDelta = Math.abs(delta);
        final int i = (int) Math.ceil((double)absDelta / 2);
        // onTopDown在顶部,并上回推和onTopUp相对
        if(mHeaderViewParams.height > 0 && delta < 0){
            mHeaderIncremental -= i;
            if(mHeaderIncremental > 0){
                setHeaderHeight(mHeaderIncremental);
                checkHeaderViewState();
            }else{
                mHeaderViewState = HEADER_VIEW_STATE_IDLE;
                mHeaderIncremental = 0;
                setHeaderHeight(mHeaderIncremental);
                mIsPullUpDone = true;
            }
            return true;
        }
        return false;
    }
    @Override
    public boolean onMotionUp(MotionEvent ev) {
        mIsDown = false;
        // 避免和点击事件冲突
        if(mHeaderViewParams.height > 0){
            // 判断头文件拉动的距离与设定的高度,小了就隐藏,多了就固定高度
            int x = mHeaderIncremental - DEFAULT_HEADER_VIEW_HEIGHT;
            Timer timer = new Timer(true);
            if(x < 0){
                timer.scheduleAtFixedRate(new HideHeaderViewTask(), 0, 10);
            }else{
                timer.scheduleAtFixedRate(new ShowHeaderViewTask(), 0, 10);
            }
            return true;
        }
        return false;
    }
}

第七步:这个java文件就是封装数据,然后调用上两个文件就好了。废话不多说,上代码:::::

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public class PullDownActivity extends Activity implements OnPullDownListener, OnItemClickListener{
    private static final int WHAT_DID_LOAD_DATA = 0;
    private static final int WHAT_DID_REFRESH = 1;
    private static final int WHAT_DID_MORE = 2;
    private ListView mListView;
    private ArrayAdapter<String> mAdapter;
    private PullDownView mPullDownView;
    private List<String> mStrings = new ArrayList<String>();
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.pulldown);
        /*
         * 1.使用PullDownView
         * 2.设置OnPullDownListener
         * 3.从mPullDownView里面获取ListView
         */
        mPullDownView = (PullDownView) findViewById(R.id.pull_down_view);
        mPullDownView.setOnPullDownListener(this);
        mListView = mPullDownView.getListView();
        mListView.setOnItemClickListener(this);
        mAdapter = new ArrayAdapter<String>(this, R.layout.pulldown_item, mStrings);
        mListView.setAdapter(mAdapter);
        mPullDownView.enableAutoFetchMore(true, 1);
        loadData();
    }
    private void loadData(){
        new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    Thread.sleep(2000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                List<String> strings = new ArrayList<String>();
                for (String body : mStringArray) {
                    strings.add(body);
                }
                Message msg = mUIHandler.obtainMessage(WHAT_DID_LOAD_DATA);
                msg.obj = strings;
                msg.sendToTarget();
            }
        }).start();
    }
    @Override
    public void onRefresh() {
        new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    Thread.sleep(2000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                Message msg = mUIHandler.obtainMessage(WHAT_DID_REFRESH);
                msg.obj = "After refresh " + System.currentTimeMillis();
                msg.sendToTarget();
            }
        }).start();
    }
    @Override
    public void onMore() {
        new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    Thread.sleep(2000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                Message msg = mUIHandler.obtainMessage(WHAT_DID_MORE);
                msg.obj = "After more " + System.currentTimeMillis();
                msg.sendToTarget();
            }
        }).start();
    }
    private Handler mUIHandler = new Handler(){
        @Override
        public void handleMessage(Message msg) {
            switch (msg.what) {
                case WHAT_DID_LOAD_DATA:{
                    if(msg.obj != null){
                        List<String> strings = (List<String>) msg.obj;
                        if(!strings.isEmpty()){
                            mStrings.addAll(strings);
                            mAdapter.notifyDataSetChanged();
                        }
                    }
                    // 诉它数据加载完毕;
                    mPullDownView.notifyDidLoad();
                    break;
                }
                case WHAT_DID_REFRESH :{
                    String body = (String) msg.obj;
                    mStrings.add(0, body);
                    mAdapter.notifyDataSetChanged();
                    // 告诉它更新完毕
                    mPullDownView.notifyDidRefresh();
                    break;
                }
                case WHAT_DID_MORE:{
                    String body = (String) msg.obj;
                    mStrings.add(body);
                    mAdapter.notifyDataSetChanged();
                    // 告诉它获取更多完毕
                    mPullDownView.notifyDidMore();
                    break;
                }
            }
        }
    };
    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
        Toast.makeText(this, "啊,你点中我了 " + position, Toast.LENGTH_SHORT).show();
    }
    // 模拟数据
    private String[] mStringArray = {
            "Abbaye de Belloc", "Abbaye du Mont des Cats", "Abertam", "Abondance", "Ackawi",
            "Acorn", "Adelost", "Affidelice au Chablis", "Afuega'l Pitu", "Airag", "Airedale",
            "Aisy Cendre", "Allgauer Emmentaler", "Alverca", "Ambert", "American Cheese"
    };
}

整个程序就这么完成了,总之,可以使用前两个封装好的文件,然后,调用就好了~~~~没什么太难的地方。

声明:本文采用 BY-NC-SA 协议进行授权,本文链接:listview下拉刷新 上拉(滑动分页)加载更多

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