Android PullToRefresh 下拉刷新，上拉很多其它，支持ScrollView，ListView，可方便拓展GridView，WebView等 _下拉刷新

弓背霞明剑照霜，秋风走马出咸阳。这篇文章主要讲述Android PullToRefresh 下拉刷新，上拉很多其它，支持ScrollView，ListView，可方便拓展GridView，WebView等相关的知识，希望能为你提供帮助。
在写着东西之前。从网上找到非常多这方面的源代码，可是基本没有找到惬意的。包含在GitHub上的比較有名的android-PullToRefresh-master。思来想去还是自己写吧。当然当中借鉴了一些别的开源代码！

废话不多说，直接上代码。凝视非常全乎，应该不难理解，Demo下载地址在最后：

package com.zs.pulltorefreshtest; import android.content.Context; import android.util.AttributeSet; import android.util.Log; import android.view.MotionEvent; import android.view.View; import android.view.ViewConfiguration; import android.view.ViewGroup; import android.widget.LinearLayout; import android.widget.ListView; import android.widget.RelativeLayout; import android.widget.ScrollView; import android.widget.Scroller; /** * 下拉刷新控件，主要測试了ScrollView，代码中已实现ListView下拉和上拉刷新，只是没有怎么測 * 至于GridView、WebView等，代码中没有实现。只是非常好拓展，在isReadyForPullUp() 和 * isReadyForPullDown()这两个方法中增加对应的View的上下边界推断就OK了 * @author zhangshuo * @version 1.0 */ public class PullToRefreshView extends RelativeLayout { /**手指滑动距离与控件移动距离的比例为2:1*/ static final float FRICTION = 2.0f; /**显示“下拉刷新”的状态*/ static final int PULL_TO_REFRESH = 0x0; /**显示“释放刷新”的状态*/ static final int RELEASE_TO_REFRESH = 0x1; /**用户通过下拉进入的刷新状态*/ static final int REFRESHING = 0x2; /**用户通过代码强制进入的刷新状态*/ static final int MANUAL_REFRESHING = 0x3; /**私有模式，不提供对外调用。 * 仅用来标示“用户下拉刷新成功后，headerView显示在头部，当用户手指向上滑动时。将headerView尾随用户滑动向上滑动” * 及“用户上拉很多其它成功后，footerView显示在底部，当用户手指向下滑动时。将footerView尾随用户滑动向下滑动”这两个过程的模式*/ private static final int MODE_PULL_TO_SCROLL_HEADER_OR_FOOTER = 0x0; /**标示当前支持下拉刷新模式*/ public static final int MODE_PULL_DOWN_TO_REFRESH = 0x1; /**标示当前支持上拉很多其它模式*/ public static final int MODE_PULL_UP_TO_REFRESH = 0x2; /**标示当前支持下拉刷新和上拉很多其它两种模式*/ public static final int MODE_BOTH = 0x3; private Context context; /**滚动对象*/ private Scroller scroller; /**推断用户手指的移动距离是否足以响应为move*/ private int touchSlop; private float initialMotionY; private float lastMotionX; private float lastMotionY; private boolean isBeingDragged = false; /**记录headerView当前的状态*/ private int headerState = PULL_TO_REFRESH; /**记录footerView当前的状态*/ private int footerState = PULL_TO_REFRESH; /**当前所支持的模式*/ private int mode = MODE_PULL_DOWN_TO_REFRESH; /**当前处于的模式*/ private int currentMode; /**依据不同的mode，contentView所在父View的位置不同，下拉刷新时为1，上拉很多其它时为1，上拉下拉都支持时为2*/ private int index = 1; /**标示当处于刷新状态时，是否须要禁用滑动*/ private boolean disableScrollingWhileRefreshing = false; /**标示是否同意滑动刷新*/ private boolean isPullToRefreshEnabled = true; private LoadingLayout headerLayout; private LoadingLayout footerLayout; private int headerHeight; /**记录当处于刷新状态时。用户继续下拉的次数*/ private int pullWithRefreshingCount = 0; /**记录当处于载入很多其它状态时，用户继续上拉的次数*/ private int pullWithLoadingMoreCount = 0; /**刷新回调接口*/ private OnRefreshListener onRefreshListener; /**载入很多其它回调接口*/ private OnLoadMoreListener onLoadMoreListener; public PullToRefreshView(Context context) { super(context); init(context, null); } public PullToRefreshView(Context context, AttributeSet attrs) { super(context, attrs); init(context, attrs); } /** * @方法描写叙述: 初始化方法 * @作者:zhangshuo * @param context * @param attrs */ private void init(Context context, AttributeSet attrs) {scroller = new Scroller(context); touchSlop = ViewConfiguration.get(context).getScaledTouchSlop(); this.context = context; this.addLoadingView(); } /** * @方法描写叙述: 依据当前模式设置，载入头部和底部布局 * @作者:zhangshuo */ public void addLoadingView() {String pullDownLabel = context .getString(R.string.pull_to_refresh_pull_down_label); String refreshingDownLabel = context .getString(R.string.pull_to_refresh_refreshing_down_label); String releaseDownLabel = context .getString(R.string.pull_to_refresh_release_down_label); String pullUpLabel = context .getString(R.string.pull_to_refresh_pull_up_label); String refreshingUpLabel = context .getString(R.string.pull_to_refresh_refreshing_up_label); String releaseUpLabel = context .getString(R.string.pull_to_refresh_release_up_label); /*载入头部和底部View*/ if (mode == MODE_PULL_DOWN_TO_REFRESH || mode == MODE_BOTH) { headerLayout = new LoadingLayout(context, MODE_PULL_DOWN_TO_REFRESH, releaseDownLabel, pullDownLabel, refreshingDownLabel); addView(headerLayout, 0, new LinearLayout.LayoutParams( ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT)); measureView(headerLayout); headerHeight = headerLayout.getMeasuredHeight(); } if (mode == MODE_PULL_UP_TO_REFRESH || mode == MODE_BOTH) { footerLayout = new LoadingLayout(context, MODE_PULL_UP_TO_REFRESH, releaseUpLabel, pullUpLabel, refreshingUpLabel); RelativeLayout.LayoutParams lp2 = new RelativeLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT); lp2.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM); addView(footerLayout, lp2); measureView(footerLayout); headerHeight = footerLayout.getMeasuredHeight(); }/*隐藏头部和底部View*/ switch (mode) { case MODE_BOTH: index = 2; setPadding(0, -headerHeight, 0, -headerHeight); break; case MODE_PULL_UP_TO_REFRESH: index = 1; setPadding(0, 0, 0, -headerHeight); break; case MODE_PULL_DOWN_TO_REFRESH: default: index = 1; setPadding(0, -headerHeight, 0, 0); break; } } /** * 在头部和底部View增加完毕后。又一次布局。以避免在隐藏headerView和footerView时会把一部分内容（contentView）隐藏 */ @Override protected void onLayout(boolean changed, int l, int t, int r, int b) { // TODO Auto-generated method stub super.onLayout(changed, l, t, r, b); View contentView = null; RelativeLayout.LayoutParams lp1 = null; switch (mode) { case MODE_BOTH: contentView = this.getChildAt(index); lp1 = (LayoutParams) contentView.getLayoutParams(); lp1.setMargins(0, headerHeight, 0, headerHeight); break; case MODE_PULL_UP_TO_REFRESH: contentView = this.getChildAt(index); lp1 = (LayoutParams) contentView.getLayoutParams(); lp1.setMargins(0, 0, 0, headerHeight); break; case MODE_PULL_DOWN_TO_REFRESH: default: contentView = this.getChildAt(index); lp1 = (LayoutParams) contentView.getLayoutParams(); lp1.setMargins(0, headerHeight, 0, 0); break; } } private void measureView(View child) { ViewGroup.LayoutParams p = child.getLayoutParams(); if (p == null) { p = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT); }int childWidthSpec = ViewGroup.getChildMeasureSpec(0, 0 + 0, p.width); int lpHeight = p.height; int childHeightSpec; if (lpHeight > 0) { childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); } else { childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); } child.measure(childWidthSpec, childHeightSpec); } @Override public final boolean onInterceptTouchEvent(MotionEvent event) {Log.e("Intercept", "start"); if (!isPullToRefreshEnabled) { return false; }if ((isLoadingMore() || isRefreshing()) & & disableScrollingWhileRefreshing) { return true; }final int action = event.getAction(); if (action == MotionEvent.ACTION_CANCEL || action == MotionEvent.ACTION_UP) { isBeingDragged = false; return false; }if (action != MotionEvent.ACTION_DOWN & & isBeingDragged) { return true; }switch (action) { case MotionEvent.ACTION_DOWN: { Log.e("Intercept", "down"); if (isReadyForPull()) { lastMotionY = initialMotionY = event.getY(); lastMotionX = event.getX(); isBeingDragged = false; } break; } case MotionEvent.ACTION_MOVE: { Log.e("Intercept", "move"); if (isReadyForPull()) { final float y = event.getY(); final float dy = y - lastMotionY; final float yDiff = Math.abs(dy); final float xDiff = Math.abs(event.getX() - lastMotionX); if (yDiff > touchSlop & & yDiff > xDiff) { if ((mode == MODE_PULL_DOWN_TO_REFRESH || mode == MODE_BOTH) & & dy > = 0.0001f & & isReadyForPullDown()) { /*能够下拉刷新*/ lastMotionY = y; isBeingDragged = true; currentMode = MODE_PULL_DOWN_TO_REFRESH; } else if ((mode == MODE_PULL_UP_TO_REFRESH || mode == MODE_BOTH) & & dy < = 0.0001f & & isReadyForPullUp()) { /*能够上拉很多其它*/ lastMotionY = y; isBeingDragged = true; currentMode = MODE_PULL_UP_TO_REFRESH; }else if((isRefreshing() & & getScrollY() < 0)|| (isLoadingMore() & & getScrollY() > 0)){ /*当前headerView或footerView处于显示状态，开启尾随手指滑动模式*/ lastMotionY = y; isBeingDragged = true; currentMode = MODE_PULL_TO_SCROLL_HEADER_OR_FOOTER; } } } break; } } return isBeingDragged; } @Override public final boolean onTouchEvent(MotionEvent event) { Log.e("Touch", "start"); if (!isPullToRefreshEnabled) { return false; }if (isRefreshing() & & disableScrollingWhileRefreshing) { return true; }if (event.getAction() == MotionEvent.ACTION_DOWN & & event.getEdgeFlags() != 0) { return false; }switch (event.getAction()) {case MotionEvent.ACTION_DOWN: { Log.e("Touch", "down"); if (isReadyForPull()) { lastMotionY = initialMotionY = event.getY(); return true; } break; } case MotionEvent.ACTION_MOVE: { Log.e("Touch", "move"); if (isBeingDragged) { lastMotionY = event.getY(); this.pullEvent(); return true; } break; } case MotionEvent.ACTION_CANCEL: case MotionEvent.ACTION_UP: { Log.e("Touch", "up"); if (isBeingDragged) { isBeingDragged = false; if(isRefreshing() & & pullWithRefreshingCount == 0){ pullWithRefreshingCount = 1; } if(isLoadingMore() & & pullWithLoadingMoreCount == 0){ pullWithLoadingMoreCount = 1; }switch (currentMode) { case MODE_PULL_TO_SCROLL_HEADER_OR_FOOTER: /*将headerView和footerView隐藏*/ smoothScrollTo(0); break; case MODE_PULL_UP_TO_REFRESH: /*推断是否激活载入很多其它*/ if (footerState == RELEASE_TO_REFRESH & & null != onLoadMoreListener) { setLoadingMoreInternal(true); onLoadMoreListener.onLoadMore(); } else { smoothScrollTo(0); } break; case MODE_PULL_DOWN_TO_REFRESH: /*推断是否激活刷新*/ if (headerState == RELEASE_TO_REFRESH & & null != onRefreshListener) { setRefreshingInternal(true); onRefreshListener.onRefresh(); } else { smoothScrollTo(0); } break; }return true; } break; } }return false; } /** * @方法描写叙述: 处理用户滑动的方法 * @作者:zhangshuo * * @return */ private boolean pullEvent() {final int newHeight; final int oldHeight = this.getScrollY(); switch (currentMode) { case MODE_PULL_TO_SCROLL_HEADER_OR_FOOTER: newHeight = Math.round((initialMotionY - lastMotionY)); break; case MODE_PULL_UP_TO_REFRESH: newHeight = Math.round(Math.max(initialMotionY - lastMotionY, 0) / FRICTION); break; case MODE_PULL_DOWN_TO_REFRESH: default: newHeight = Math.round(Math.min(initialMotionY - lastMotionY, 0) / FRICTION); break; }if(isRefreshing() & & pullWithRefreshingCount == 0){ /*处于刷新状态下，第一次继续下拉。此时headerView已经显示在头部*/ if((-headerHeight + newHeight) < 0){ scrollTo(-headerHeight + newHeight); }else{ scrollTo(0); if(((ScrollView)getChildAt(index)).getChildAt(0).getHeight() > getChildAt(index).getHeight()){ getChildAt(index).scrollTo(0, newHeight - headerHeight); } } }else if(isLoadingMore() & & pullWithLoadingMoreCount == 0){ /*处于刷新状态下。第一次继续下拉。此时headerView已经显示在头部*/ if((headerHeight + newHeight) > 0){ scrollTo(headerHeight + newHeight); }else{ scrollTo(0); if(((ScrollView)getChildAt(index)).getChildAt(0).getHeight() > getChildAt(index).getHeight()){ getChildAt(index).scrollTo(0, newHeight + headerHeight + ((ScrollView)getChildAt(index)).getChildAt(0).getHeight() - getChildAt(index).getHeight()); } } }else{ scrollTo(newHeight); }if (newHeight != 0) {switch (currentMode) { case MODE_PULL_UP_TO_REFRESH: if (footerState == PULL_TO_REFRESH & & headerHeight < Math.abs(newHeight)) { footerState = RELEASE_TO_REFRESH; footerLayout.releaseToRefresh(); return true; } else if (footerState == RELEASE_TO_REFRESH & & headerHeight > = Math.abs(newHeight)) { footerState = PULL_TO_REFRESH; footerLayout.pullToRefresh(); return true; } break; case MODE_PULL_DOWN_TO_REFRESH: if (headerState == PULL_TO_REFRESH & & headerHeight < Math.abs(newHeight)) { headerState = RELEASE_TO_REFRESH; headerLayout.releaseToRefresh(); return true; } else if (headerState == RELEASE_TO_REFRESH & & headerHeight > = Math.abs(newHeight)) { headerState = PULL_TO_REFRESH; headerLayout.pullToRefresh(); return true; } break; }}return oldHeight != newHeight; } /** * @方法描写叙述: 推断当前状态能否够进行上拉很多其它或下拉刷新的滑动操作 * @作者:zhangshuo * @return */ private boolean isReadyForPull() { switch (mode) { case MODE_PULL_DOWN_TO_REFRESH: return isReadyForPullDown(); case MODE_PULL_UP_TO_REFRESH: return isReadyForPullUp(); case MODE_BOTH: return isReadyForPullUp() || isReadyForPullDown(); } return false; } /** * @方法描写叙述: 推断当前状态能否够进行下拉刷新操作 * @作者:zhangshuo * @return */ private boolean isReadyForPullDown() { // TODO Auto-generated method stub if (getChildCount() > 1) { Log.e("Ready--down", String.valueOf(getChildCount())); View childView = this.getChildAt(index); if (childView instanceof ListView) { int top = ((ListView) childView).getChildAt(0).getTop(); int pad = ((ListView) childView).getListPaddingTop(); if ((Math.abs(top - pad)) < 3 & & ((ListView) childView).getFirstVisiblePosition() == 0) { return true; } else { return false; } } else if (childView instanceof ScrollView) { Log.e("Ready--down", "scrollView"); if (((ScrollView) childView).getScrollY() == 0) { return true; } else { return false; } }} return false; } /** * @方法描写叙述:推断当前状态能否够上拉很多其它的滑动操作 * @作者:zhangshuo * @return */ private boolean isReadyForPullUp() { // TODO Auto-generated method stub if (getChildCount() > 1) { Log.e("Ready--up", String.valueOf(getChildCount())); View childView = this.getChildAt(index); if (childView instanceof ListView) { int top = ((ListView) childView).getChildAt( ((ListView) childView).getCount()).getBottom(); int pad = ((ListView) childView).getListPaddingBottom(); if ((Math.abs(top - pad)) < 3 & & ((ListView) childView).getFirstVisiblePosition() == ((ListView) childView) .getCount()) { return true; } else { return false; } } else if (childView instanceof ScrollView) { Log.e("Ready--up", "scrollView"); int off = ((ScrollView) childView).getScrollY() + ((ScrollView) childView).getHeight() - ((ScrollView) childView).getChildAt(0).getHeight(); if (off > = 0) { return true; } else { return false; } }} return false; } /** * @方法描写叙述: 是否同意上拉很多其它或下拉刷新的滑动操作 * @作者:zhangshuo * @return */ public final boolean isPullToRefreshEnabled() { return isPullToRefreshEnabled; } /** * @方法描写叙述: 当处于刷新状态时，是否须要禁用滑动 * @作者:zhangshuo * @return */ public final boolean isDisableScrollingWhileRefreshing() { return disableScrollingWhileRefreshing; } /** * @方法描写叙述: 当前正处于刷新中 * @作者:zhangshuo * @return */ public final boolean isRefreshing() { return headerState == REFRESHING || headerState == MANUAL_REFRESHING; } /** * @方法描写叙述: 当前正处于载入很多其它中 * @作者:zhangshuo * @return */ public final boolean isLoadingMore() { return footerState == REFRESHING || footerState == MANUAL_REFRESHING; } /** * @方法描写叙述:设置当处于刷新状态时。是否须要禁用滑动 * @作者:zhangshuo * @param disableScrollingWhileRefreshing */ public final void setDisableScrollingWhileRefreshing( boolean disableScrollingWhileRefreshing) { this.disableScrollingWhileRefreshing = disableScrollingWhileRefreshing; } /** * @方法描写叙述: 结束刷新状态 * @作者:zhangshuo * */ public final void onRefreshComplete() { if (headerState != PULL_TO_REFRESH) { resetHeader(); } pullWithRefreshingCount = 0; } /** * @方法描写叙述: 结束载入很多其它状态 * @作者:zhangshuo * */ public final void onLoadMoreComplete() { if (footerState != PULL_TO_REFRESH) { resetFooter(); } pullWithLoadingMoreCount = 0; } /** * @方法描写叙述: 设置否同意滑动刷新 * @作者:zhangshuo * @param enable */ public final void setPullToRefreshEnabled(boolean enable) { this.isPullToRefreshEnabled = enable; } /** * @方法描写叙述: 强制设置为刷新状态 * @作者:zhangshuo */ public final void setRefreshing() { this.setRefreshing(true); } /** * @方法描写叙述: 强制设置为载入很多其它状态 * @作者:zhangshuo */ public final void setLoadingMore(){ this.setLoadingMore(true); } /** * @方法描写叙述: 强制设置为刷新状态 * @作者:zhangshuo * @param doScroll */ public final void setRefreshing(boolean doScroll) { if (!isRefreshing()) { setRefreshingInternal(doScroll); headerState = MANUAL_REFRESHING; } } /** * @方法描写叙述: 强制设置为载入很多其它状态 * @作者:zhangshuo * @param doScroll */ public final void setLoadingMore(boolean doScroll) { if (!isLoadingMore()) { setLoadingMoreInternal(doScroll); footerState = MANUAL_REFRESHING; } } protected final int getCurrentMode() { return currentMode; } protected final LoadingLayout getFooterLayout() { return footerLayout; } protected final LoadingLayout getHeaderLayout() { return headerLayout; } protected final int getHeaderHeight() { return headerHeight; } protected final int getMode() { return mode; } /** * @方法描写叙述: 重置headerView * @作者:zhangshuo */ protected void resetHeader() { headerState = PULL_TO_REFRESH; isBeingDragged = false; if (null != headerLayout) { headerLayout.reset(); }smoothScrollTo(0); } /** * @方法描写叙述: 重置footerView * @作者:zhangshuo */ protected void resetFooter() { footerState = PULL_TO_REFRESH; isBeingDragged = false; if (null != footerLayout) { footerLayout.reset(); }smoothScrollTo(0); } /** * @方法描写叙述: 强制设置为刷新状态，并显示出headerView * @作者:zhangshuo * @param doScroll */ protected void setRefreshingInternal(boolean doScroll) { headerState = REFRESHING; pullWithRefreshingCount = 0; if (null != headerLayout) { headerLayout.refreshing(); }if (doScroll) { smoothScrollTo(-headerHeight); } } /** * @方法描写叙述: 强制设置为载入很多其它状态，并显示出footerView * @作者:zhangshuo * @param doScroll */ protected void setLoadingMoreInternal(boolean doScroll) { footerState = REFRESHING; pullWithLoadingMoreCount = 0; if (null != footerLayout) { footerLayout.refreshing(); }if (doScroll) { smoothScrollTo(headerHeight); } } protected final void scrollTo(int y) { scrollTo(0, y); } protected final void smoothScrollTo(int y) {scroller.startScroll(0, getScrollY(), 0, -(getScrollY() - y), 500); invalidate(); } @Override public void computeScroll() { // TODO Auto-generated method stub if (scroller.computeScrollOffset()) { scrollTo(0, this.scroller.getCurrY()); postInvalidate(); } } /** * @方法描写叙述: 设置刷新回调接口 * @作者:zhangshuo * @param listener */ public final void setOnRefreshListener(OnRefreshListener listener) { this.onRefreshListener = listener; } /** * @方法描写叙述: 设置载入很多其它回调接口 * @作者:zhangshuo * @param listener */ public final void setOnLoadMoreListener(OnLoadMoreListener listener){ this.onLoadMoreListener= listener; } /** * @CLASS:OnRefreshListener * @描写叙述: 刷新回调接口 * @作者:zhangshuo * @版本号:v1.0 * @日期:2014年7月15日上午11:59:50 */ public static interface OnRefreshListener {public void onRefresh(); } /** * @CLASS:OnLoadMoreListener * @描写叙述: 载入很多其它回调接口 * @作者:zhangshuo * @版本号:v1.0 * @日期:2014年7月15日下午12:00:06 */ public static interface OnLoadMoreListener {public void onLoadMore(); }}