WebView 下拉刷新

下拉刷新已经是非常常见的效果了，那么也有很多优秀的控件。

这里分享的是用refreshlayout 思想开发自定义控件。

优点代码更加简洁，修改起来更加方便。

源码：

public class WebViewRefreshLayout extends LinearLayout implementsOnTouchListener {RelativeLayout header;TextView description;boolean loadOnce;int hideHeaderHeight;MarginLayoutParams headerLayoutParams;WebView webView;Context context;boolean ableToPull;float yDown;int touchSlop;int PULL =0;int RELEASA=1;int REFRESHING=2;int END=3;int currentStatus = END;int lastStatus = currentStatus;Runnable mListener;int pullTime = 200;public WebViewRefreshLayout(Context context, AttributeSet attrs) {super(context, attrs);this.context = context;touchSlop = ViewConfiguration.get(context).getScaledTouchSlop();}@Overrideprotected void onLayout(boolean changed, int l, int t, int r, int b) {super.onLayout(changed, l, t, r, b);if (changed && !loadOnce) {loadOnce = true;header = (RelativeLayout) getChildAt(0);description = (TextView)header.getChildAt(0);webView = (WebView) getChildAt(1);webView.setOnTouchListener(this);hideHeaderHeight = -header.getHeight();headerLayoutParams = (MarginLayoutParams) header.getLayoutParams();headerLayoutParams.topMargin = hideHeaderHeight;header.setLayoutParams(headerLayoutParams);}}@Overridepublic boolean onTouch(View arg0, MotionEvent arg1) {setIsAbleToPull(arg1);if (ableToPull) {switch (arg1.getAction()) {case MotionEvent.ACTION_DOWN:yDown = arg1.getRawY();break;case MotionEvent.ACTION_MOVE:int distance=(int)(arg1.getRawY()-yDown);if (distance<=0 && headerLayoutParams.topMargin <= hideHeaderHeight) {return false;}if (distance<touchSlop) {return false;}if (currentStatus!=REFRESHING) {if (headerLayoutParams.topMargin>0) {currentStatus = RELEASA;}else {currentStatus = PULL;}headerLayoutParams.topMargin = (distance/2)+hideHeaderHeight;header.setLayoutParams(headerLayoutParams);}break;case MotionEvent.ACTION_UP:default:if (currentStatus==RELEASA) {RefreshingTask();}if (currentStatus==PULL) {HideHeaderTask();}break;}if (currentStatus==RELEASA|| currentStatus==PULL) {updateHeaderView();webView.setPressed(false);webView.setFocusable(false);webView.setFocusableInTouchMode(true);lastStatus=currentStatus;return true;}}return false;}private void HideHeaderTask() {// TODO Auto-generated method stubValueAnimator valueAnimator=ValueAnimator.ofInt(headerLayoutParams.topMargin, hideHeaderHeight);valueAnimator.setDuration(pullTime);valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {@Overridepublic void onAnimationUpdate(ValueAnimator arg0) {// TODO Auto-generated method stubint integer=((Integer)arg0.getAnimatedValue()).intValue();headerLayoutParams.topMargin = integer;header.setLayoutParams(headerLayoutParams);if (integer==hideHeaderHeight) {currentStatus = END;}updateHeaderView();}});valueAnimator.start();}private void RefreshingTask() {ValueAnimator valueAnimator = ValueAnimator.ofInt(headerLayoutParams.topMargin, 0);valueAnimator.setDuration(pullTime);valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {@Overridepublic void onAnimationUpdate(ValueAnimator arg0) {int integer=((Integer)arg0.getAnimatedValue()).intValue();headerLayoutParams.topMargin = integer;header.setLayoutParams(headerLayoutParams);if (integer == 0) {currentStatus = REFRESHING;if (mListener!=null) {mListener.run();}}updateHeaderView();}});valueAnimator.start();}public void setOnRefreshListener(Runnable pullToRefreshListener){mListener = pullToRefreshListener;}private void updateHeaderView() {if (lastStatus!=currentStatus) {if (currentStatus==RELEASA) {description.setText("放手回到上面");}else if (currentStatus==PULL) {description.setText("下拉回到上面");}else if (currentStatus==REFRESHING) {description.setText("正在加载");}}}private void setIsAbleToPull(MotionEvent arg1) {if (webView.getScrollY() <= 0) {if (!ableToPull) {yDown = arg1.getRawY();}ableToPull = true;} else {if (headerLayoutParams.topMargin != hideHeaderHeight) {headerLayoutParams.topMargin = hideHeaderHeight;header.setLayoutParams(headerLayoutParams);}ableToPull = false;}}public void finishRefreshing(){currentStatus = END;HideHeaderTask();}}

xml布局：

            <com.example.mydome.WebViewRefreshLayout                android:id="@+id/webview_shop_content"                android:layout_width="match_parent"                android:layout_height="match_parent"                android:orientation="vertical"                android:visibility="visible" >                <!-- 下拉刷新头部开始 -->                <RelativeLayout                    android:layout_width="match_parent"                    android:layout_height="wrap_content"                    android:padding="17dp" >                    <TextView                        android:layout_width="match_parent"                        android:layout_height="wrap_content"                        android:gravity="center"                        android:text="下拉回到上面" />                </RelativeLayout>                <!-- 下拉刷新头部结束 -->                <WebView                    android:id="@+id/shop_webview"                    android:layout_width="match_parent"                    android:layout_height="match_parent" />            </com.example.mydome.WebViewRefreshLayout>

使用代码：

webViewRefreshLayout.setOnRefreshListener(new Runnable() {@Overridepublic void run() {//PrevPage();//刷新执行代码handler.postDelayed(new Runnable() {@Overridepublic void run() {// 数据加载完毕后执行的回收头部操作webViewRefreshLayout.finishRefreshing();}}, 3000);}});