Skip to content

Instantly share code, notes, and snippets.

Embed
What would you like to do?
NestedScrollViewScrollToAction because regular ScrollTo doesn't work
package com.example.NestedScrollViewScrollToAction;
import android.graphics.Rect;
import android.support.design.widget.CoordinatorLayout;
import android.support.test.espresso.PerformException;
import android.support.test.espresso.UiController;
import android.support.test.espresso.ViewAction;
import android.support.test.espresso.matcher.ViewMatchers.Visibility;
import android.support.test.espresso.util.HumanReadables;
import android.support.v4.widget.NestedScrollView;
import android.util.Log;
import android.view.View;
import org.hamcrest.Matcher;
import static android.support.test.espresso.matcher.ViewMatchers.isAssignableFrom;
import static android.support.test.espresso.matcher.ViewMatchers.isDescendantOfA;
import static android.support.test.espresso.matcher.ViewMatchers.isDisplayingAtLeast;
import static android.support.test.espresso.matcher.ViewMatchers.withEffectiveVisibility;
import static org.hamcrest.Matchers.allOf;
import static org.hamcrest.Matchers.anyOf;
/**
* Enables scrolling to the given view. View must be a descendant of a ScrollView.
*/
public final class NestedScrollViewScrollToAction implements ViewAction {
private static final String TAG = NestedScrollViewScrollToAction.class.getSimpleName();
public static NestedScrollViewScrollToAction scrollTo() {
return new NestedScrollViewScrollToAction();
}
@SuppressWarnings("unchecked")
@Override
public Matcher<View> getConstraints() {
return allOf(withEffectiveVisibility(Visibility.VISIBLE), isDescendantOfA(anyOf(
isAssignableFrom(NestedScrollView.class))));
}
@Override
public void perform(UiController uiController, View view) {
if (isDisplayingAtLeast(90).matches(view)) {
Log.i(TAG, "View is already displayed. Returning.");
return;
}
View parentScrollView = findScrollView(view);
CoordinatorLayout.LayoutParams params = (CoordinatorLayout.LayoutParams) parentScrollView.getLayoutParams();
params.setBehavior(null);
parentScrollView.requestLayout();
uiController.loopMainThreadUntilIdle();
Rect rect = new Rect();
view.getDrawingRect(rect);
if (!view.requestRectangleOnScreen(rect, true /* immediate */)) {
Log.w(TAG, "Scrolling to view was requested, but none of the parents scrolled.");
}
uiController.loopMainThreadUntilIdle();
if (!isDisplayingAtLeast(90).matches(view)) {
throw new PerformException.Builder()
.withActionDescription(this.getDescription())
.withViewDescription(HumanReadables.describe(view))
.withCause(new RuntimeException(
"Scrolling to view was attempted, but the view is not displayed"))
.build();
}
}
private View findScrollView(View view) {
View parent = (View) view.getParent();
if (parent != null) {
if (parent instanceof NestedScrollView) {
return parent;
}
return findScrollView(parent);
}
throw new PerformException.Builder()
.withActionDescription(this.getDescription())
.withViewDescription(HumanReadables.describe(view))
.withCause(new RuntimeException(
"Scrolling aborted due to not being NestedScrollView child"))
.build();
}
@Override
public String getDescription() {
return "scroll to";
}
}
@mattj1

This comment has been minimized.

Copy link

mattj1 commented Oct 25, 2016

I hacked in some code to make it work if the NestedScrollView was inside a ViewPager

    // Find parent view that has CoordinatorLayout.LayoutParams -Matt
    View view2 = parentScrollView;
    while(true) {
        if(view2.getLayoutParams() instanceof CoordinatorLayout.LayoutParams) {
            CoordinatorLayout.LayoutParams params = (CoordinatorLayout.LayoutParams) view2.getLayoutParams();
            params.setBehavior(null);
            break;
        }
        view2 = (View) view2.getParent();
    }

// CoordinatorLayout.LayoutParams params = (CoordinatorLayout.LayoutParams) parentScrollView.getLayoutParams();
// params.setBehavior(null);
parentScrollView.requestLayout();

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
You can’t perform that action at this time.