WebView getScrollY() always returns 0

问题

Im trying to use the webview's scroll position to determine whether SwipeRefreshLayout should be able to refresh, except for some websites e.g. https://jobs.lever.co/memebox, getScrollY() always returns 0. Is there a way to ensure I will always get the correct scroll position?

回答1:

The site you linked has a fixed header. My guess is that the page itself doesn't scroll; a container inside it does. The WebView can't inspect every scrollable container on the page, so it sees that the top-level container doesn't scroll and assumes that the entire thing is fixed.

If all you need this for is pull-to-refresh, I'd recommend adding a refresh button in addition to the SwipeRefreshLayout.

回答2:

Maybe you can try to add this to your custom webview

just tell it's scrolling

 @Override
public boolean onTouchEvent(MotionEvent event) {
    switch (event.getAction()){
        case MotionEvent.ACTION_DOWN:
            if(this.getScrollY() <= 0){
                this.scrollTo(0,1);
            }
            break;
        case MotionEvent.ACTION_UP:
            break;
    }
    return super.onTouchEvent(event);
}

and then override onScrollChanged

 @Override
protected void onScrollChanged(int l, int t, int oldl, int oldt) {
    super.onScrollChanged(l, t, oldl, oldt);;
    if (iWebViewScrollListener != null && t == 0) {
        iWebViewScrollListener .onTop();
    } else if (mIWebViewScroll != null && t != 0) {
        iWebViewScrollListener .notOnTop();
    }
}

add an top listener call back when scrolling.When is onTop() use setEnabled(true) for SwipeRefreshLayout,else setEnabled(false)

回答3:

Check your web layout. position: relative; in your CSS might be the source of your problem. Relative positioning causes troubles with scrolling in the WebView.

回答4:

This is a bit old but this problem still exists. For anyone wondering, I solved this by doing the following.

In GestureListener:

private class GestureListener extends GestureDetector.SimpleOnGestureListener {

    @Override
    public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {

        if(distanceY>0) webView.scrollBy(0,1);
        else webView.scrollBy(0,-1);
    }
}

Now it's possible to enable/disable the swipeRefreshLayout correctly using getScrollY as below:

swipeLayout.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
    @Override
    public void onGlobalLayout() {
        ViewTreeObserver observer = swipeLayout.getViewTreeObserver();
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
            observer.removeOnGlobalLayoutListener(this);
        } else {
            observer.removeGlobalOnLayoutListener(this);
        }
        observer.addOnScrollChangedListener(new ViewTreeObserver.OnScrollChangedListener() {
            @Override
            public void onScrollChanged() {

                if (webView.getScrollY()==0) {
                    swipeLayout.setEnabled(true);
                } else {
                    swipeLayout.setEnabled(false);
                }
            }
        });
    }
});

来源：https://stackoverflow.com/questions/29134082/webview-getscrolly-always-returns-0

标签

android

android-webview