SwipeRefreshLayout + WebView when scroll position is at top

Question

I'm trying to use SwipeRefreshLayout with WebView.

I'm facing the problem where in the middle of page, when user scrolls down, unwanted refresh kicks in.

How do I make the refresh event only happen when webview's scroll position is at the top. (ie, he's looking at the top portion of the page)?

Answer 1

I've managed to solve it without having to extend anything. Have a look at this snippet (Fragment-specific):

private ViewTreeObserver.OnScrollChangedListener mOnScrollChangedListener;

@Override
public void onStart() {
    super.onStart();

    swipeLayout.getViewTreeObserver().addOnScrollChangedListener(mOnScrollChangedListener =
            new ViewTreeObserver.OnScrollChangedListener() {
                @Override
                public void onScrollChanged() {
                    if (mWebView.getScrollY() == 0)
                        swipeLayout.setEnabled(true);
                    else
                        swipeLayout.setEnabled(false);

                }
            });
}

@Override
public void onStop() {
    swipeLayout.getViewTreeObserver().removeOnScrollChangedListener(mOnScrollChangedListener);
    super.onStop();
}

For a broader context, have a look at my answer to Android - SwipeRefreshLayout with empty textview.

Answer 2

I think the recommended way of doing this is to extend the SwipeRefreshLayout and override canChildScrollUp() - https://developer.android.com/reference/android/support/v4/widget/SwipeRefreshLayout.html#canChildScrollUp()

This is how it's done in the Google IO 2014 Schedule app - https://github.com/google/iosched/blob/master/android/src/main/java/com/google/samples/apps/iosched/ui/widget/MultiSwipeRefreshLayout.java#L76

The CustomSwipeRefreshLayout will probably look like:

public class CustomSwipeRefreshLayout extends SwipeRefreshLayout {

    private CanChildScrollUpCallback mCanChildScrollUpCallback;

    public interface CanChildScrollUpCallback {
        boolean canSwipeRefreshChildScrollUp();
    }

    public void setCanChildScrollUpCallback(CanChildScrollUpCallback canChildScrollUpCallback) {
        mCanChildScrollUpCallback = canChildScrollUpCallback;
    }

    @Override
    public boolean canChildScrollUp() {
        if (mCanChildScrollUpCallback != null) {
            return mCanChildScrollUpCallback.canSwipeRefreshChildScrollUp();
        }
        return super.canChildScrollUp();
    }
}

And in your Activity that has the WebView,

public class FooActivity
        implements CustomSwipeRefreshLayout.CanChildScrollUpCallback {

    private CustomSwipeRefreshLayout mRefreshLayout;
    private WebView mWebView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // after initialization
        mRefreshLayout.setCanChildScrollUpCallback(this);
    }

    @Override
    public boolean canSwipeRefreshChildScrollUp() {
        return mWebview.getScrollY() > 0;
    }
}

Answer 3

Just implement your Fragment or Activity with ViewTreeObserver.OnScrollChangedListener then set Listener like webview.getViewTreeObserver().addOnScrollChangedListener(this);

In onScrollChanged() method do like this

    @Override
    public void onScrollChanged() {
        if (webview.getScrollY() == 0) {
            swipeLayout.setEnabled(true);
        } else {
            swipeLayout.setEnabled(false);
        }
    }