我需要知道如何检测用户是否无法在webView中滚动.我想在用户向左或向右滑动时生成一个动作,但仅当用户无法滚动时:
IF the user swipes to the left AND the webview can't scroll to left THEN do something ELSE let the webview scroll
解决方法
我找到了一个适合我的解决方案,我在2.3 API中检查了类WebView的源代码,并找到了如何使用2.1 API.也许它适用于较旧的API:
public class CustomWebView extends WebView { private float oldX; // indicate if horizontal scrollbar can't go more to the left private boolean overScrollLeft = false; // indicate if horizontal scrollbar can't go more to the right private boolean overScrollRight = false; // indicate if horizontal scrollbar can't go more to the left OR right private boolean isScrolling = false; public CustomWebView(Context context) { super(context); // TODO Auto-generated constructor stub } public CustomWebView(Context context,AttributeSet attrs,int defStyle) { super(context,attrs,defStyle); // TODO Auto-generated constructor stub } public CustomWebView(Context context,AttributeSet attrs) { super(context,attrs); // TODO Auto-generated constructor stub } @Override public boolean onTouchEvent(MotionEvent event) { // width of the vertical scrollbar int scrollBarWidth = getVerticalScrollbarWidth(); // width of the view depending of you set in the layout int viewWidth = computeHorizontalScrollExtent(); // width of the webpage depending of the zoom int innerWidth = computeHorizontalScrollRange(); // position of the left side of the horizontal scrollbar int scrollBarLeftPos = computeHorizontalScrollOffset(); // position of the right side of the horizontal scrollbar,the width of scroll is the width of view minus the width of vertical scrollbar int scrollBarRightPos = scrollBarLeftPos + viewWidth - scrollBarWidth; // if left pos of scroll bar is 0 left over scrolling is true if(scrollBarLeftPos == 0) { overScrollLeft = true; } else { overScrollLeft = false; } // if right pos of scroll bar is superior to webpage width: right over scrolling is true if(scrollBarRightPos >= innerWidth) { overScrollRight = true; } else { overScrollRight = false; } switch (event.getAction()) { case MotionEvent.ACTION_DOWN: // when user touch the screen // if scrollbar is the most left or right if(overScrollLeft || overScrollRight) { isScrolling = false; } else { isScrolling = true; } oldX = event.getX(); break; case MotionEvent.ACTION_UP: // when user stop to touch the screen // if scrollbar can't go more to the left OR right // this allow to force the user to do another gesture when he reach a side if(!isScrolling) { if(event.getX() > oldX && overScrollLeft) { // left action } if(event.getX() < oldX && overScrollRight) { // right actio } } break; default: break; } return super.onTouchEvent(event); } }