// Copyright 2017 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
package org.chromium.components.browser_ui.widget;
import android.view.View;
import android.view.ViewParent;
import androidx.recyclerview.widget.RecyclerView;
import androidx.recyclerview.widget.RecyclerView.LayoutManager;
import androidx.recyclerview.widget.RecyclerView.ViewHolder;
import org.hamcrest.Description;
import org.hamcrest.Matcher;
import org.hamcrest.Matchers;
import org.hamcrest.TypeSafeMatcher;
import org.chromium.base.ThreadUtils;
import org.chromium.base.test.util.CallbackHelper;
import org.chromium.base.test.util.Criteria;
import org.chromium.base.test.util.CriteriaHelper;
import org.chromium.ui.modelutil.PropertyModel;
import org.chromium.ui.modelutil.SimpleRecyclerViewAdapter;
import java.util.concurrent.TimeoutException;
/**
* Utilities for {@link RecyclerView}, to handle waiting for animation changes and other potential
* flakiness sources.
*/
public final class RecyclerViewTestUtils {
private RecyclerViewTestUtils() {}
public static RecyclerView.ViewHolder waitForView(
final RecyclerView recyclerView, final int position) {
CriteriaHelper.pollUiThread(
() -> {
RecyclerView.ViewHolder viewHolder =
recyclerView.findViewHolderForAdapterPosition(position);
Criteria.checkThat(
"Cannot find view holder for position " + position + ".",
viewHolder,
Matchers.notNullValue());
Criteria.checkThat(
"The view is not attached for position " + position + ".",
viewHolder.itemView.getParent(),
Matchers.notNullValue());
Criteria.checkThat(
"The view is not visible for position " + position + ".",
viewHolder.itemView.isShown(),
Matchers.is(true));
});
waitForStableRecyclerView(recyclerView);
return recyclerView.findViewHolderForAdapterPosition(position);
}
public static void waitForViewToDetach(final RecyclerView recyclerView, final View view)
throws TimeoutException {
final CallbackHelper callback = new CallbackHelper();
recyclerView.addOnChildAttachStateChangeListener(
new RecyclerView.OnChildAttachStateChangeListener() {
@Override
public void onChildViewAttachedToWindow(View view) {}
@Override
public void onChildViewDetachedFromWindow(View detachedView) {
if (detachedView == view) {
recyclerView.removeOnChildAttachStateChangeListener(this);
callback.notifyCalled();
}
}
});
callback.waitForCallback("The view did not detach.", 0);
waitForStableRecyclerView(recyclerView);
}
/**
* Tries to wait for changes and animations to {@link RecyclerView} to finish happening. This
* works especially well for animations, but not as well when just underlying model changes
* happen though the {@link RecyclerView.Adapter}.
*/
public static void waitForStableRecyclerView(final RecyclerView recyclerView) {
CriteriaHelper.pollUiThread(() -> checkForStableRecyclerView(recyclerView));
}
/**
* In addition to the checks in {@link #waitForStableRecyclerView(RecyclerView)}, also checks
* all of the PropertyModels. This will make sure all of the view binding has completed.
*/
public static void waitForStableMvcRecyclerView(RecyclerView recyclerView) {
CriteriaHelper.pollUiThread(
() -> {
SimpleRecyclerViewAdapter adapter =
(SimpleRecyclerViewAdapter) recyclerView.getAdapter();
int viewCount = recyclerView.getChildCount();
int adapterCount = adapter.getModelList().size();
Criteria.checkThat(
"Views can be lazily created, but shouldn't have extra.",
viewCount,
Matchers.lessThanOrEqualTo(adapterCount));
for (int i = 0; i < viewCount; i++) {
View child = recyclerView.getChildAt(i);
SimpleRecyclerViewAdapter.ViewHolder viewHolder =
(SimpleRecyclerViewAdapter.ViewHolder)
recyclerView.getChildViewHolder(child);
PropertyModel viewModel = viewHolder.model;
PropertyModel adapterModel = adapter.getModelList().get(i).model;
Criteria.checkThat(
"Models should be the same at index " + i,
viewModel,
Matchers.equalTo(adapterModel));
}
checkForStableRecyclerView(recyclerView);
});
}
/**
* Scrolls the {@link View} at the given adapter position into view and returns its {@link
* RecyclerView.ViewHolder}.
*
* @param recyclerView the {@link RecyclerView} to scroll.
* @param position the adapter position for which to return the {@link RecyclerView.ViewHolder}.
* @return the ViewHolder for the given {@code position}.
*/
public static RecyclerView.ViewHolder scrollToView(RecyclerView recyclerView, int position) {
ThreadUtils.runOnUiThreadBlocking(() -> recyclerView.scrollToPosition(position));
return waitForView(recyclerView, position);
}
/** Scrolls the {@link RecyclerView} to the bottom. */
public static void scrollToBottom(RecyclerView recyclerView) {
ThreadUtils.runOnUiThreadBlocking(
() -> {
// Scroll to bottom.
recyclerView.scrollToPosition(recyclerView.getAdapter().getItemCount() - 1);
});
// Wait until we can scroll no further.
// A positive parameter checks scrolling down, a negative one scrolling up.
CriteriaHelper.pollUiThread(() -> !recyclerView.canScrollVertically(1));
}
/**
* The {@link RecyclerView} will respond to changes, particularly things like
* {@link androidx.recyclerview.widget.RecyclerView.Adapter#notifyItemChanged(int)} by
* immediately creating a new {@link View}, but asynchronously removing the old Views. The
* generic {@link ViewParent} interface methods that Espresso is using to access children
* may return stale information. This often results in
* {@link androidx.test.espresso.AmbiguousViewMatcherException}. This matcher utilizes our
* knowledge that the view must be rooted somewhere within a RecycleView, to use RecyclerView
* specific methods to verify if the View is still active or not.
*/
public static Matcher<View> activeInRecyclerView() {
return new ActiveInRecyclerViewMatcher();
}
private static class ActiveInRecyclerViewMatcher extends TypeSafeMatcher<View> {
@Override
protected boolean matchesSafely(View view) {
View topChild = getTopChild(view);
if (topChild == null) {
return false;
}
RecyclerView recyclerView = (RecyclerView) topChild.getParent();
LayoutManager layoutManager = recyclerView.getLayoutManager();
ViewHolder viewHolder = recyclerView.getChildViewHolder(topChild);
// The ViewHolder's index maybe be stale for Views that have been removed. Instead
// believe what the RecyclerView/LayoutManager claims is the top child view at the give
// index.
View activeChild = layoutManager.getChildAt(viewHolder.getLayoutPosition());
return topChild == activeChild;
}
/**
* Returns the top most child under the RecyclerView. This is the View with the ViewHolder.
* Often this matcher is called on view that's much farther down.
*/
private static View getTopChild(View view) {
View previous = view;
while (true) {
if (previous == null || !(previous.getParent() instanceof View)) {
return null;
}
View current = (View) previous.getParent();
if (current instanceof RecyclerView) {
return previous;
}
previous = current;
}
}
@Override
public void describeTo(Description description) {
description.appendText("Not the active view in RecyclerView");
}
}
private static void checkForStableRecyclerView(RecyclerView recyclerView) {
Criteria.checkThat(
"The recycler view is computing layout.",
recyclerView.isComputingLayout(),
Matchers.is(false));
Criteria.checkThat(
"The recycler view layout is frozen.",
recyclerView.isLayoutFrozen(),
Matchers.is(false));
Criteria.checkThat(
"The recycler view is animating.", recyclerView.isAnimating(), Matchers.is(false));
Criteria.checkThat(
"The recycler view is dirty.", recyclerView.isDirty(), Matchers.is(false));
Criteria.checkThat(
"The recycler view has layout requested.",
recyclerView.isLayoutRequested(),
Matchers.is(false));
}
}
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