ViewFinderImpl.java
/*
* Copyright (C) 2014 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package androidx.test.espresso.base;
import static androidx.test.espresso.util.TreeIterables.breadthFirstViewTraversal;
import static androidx.test.internal.util.Checks.checkMainThread;
import static androidx.test.internal.util.Checks.checkNotNull;
import android.view.View;
import android.widget.AdapterView;
import androidx.test.espresso.AmbiguousViewMatcherException;
import androidx.test.espresso.NoMatchingViewException;
import androidx.test.espresso.ViewFinder;
import androidx.test.espresso.matcher.ViewMatchers;
import androidx.test.espresso.util.IterablesKt;
import androidx.test.espresso.util.Iterators;
import androidx.test.espresso.util.StringJoinerKt;
import java.util.Iterator;
import java.util.List;
import java.util.Locale;
import javax.inject.Inject;
import javax.inject.Provider;
import org.hamcrest.Matcher;
/** Implementation of {@link ViewFinder}. */
// TODO: in the future we may want to collect stats here about the size of the view
// hierarchy, average matcher execution time, warn when matchers take too long to execute, etc.
public final class ViewFinderImpl implements ViewFinder {
private final Matcher<View> viewMatcher;
private final Provider<View> rootViewProvider;
@Inject
ViewFinderImpl(Matcher<View> viewMatcher, Provider<View> rootViewProvider) {
this.viewMatcher = viewMatcher;
this.rootViewProvider = rootViewProvider;
}
@Override
public View getView() throws AmbiguousViewMatcherException, NoMatchingViewException {
checkMainThread();
checkNotNull(viewMatcher);
View root = rootViewProvider.get();
Iterator<View> matchedViewIterator =
IterablesKt.filter(breadthFirstViewTraversal(root), viewMatcher).iterator();
View matchedView = null;
while (matchedViewIterator.hasNext()) {
if (matchedView != null) {
// Ambiguous!
throw new AmbiguousViewMatcherException.Builder()
.withViewMatcher(viewMatcher)
.withRootView(root)
.withView1(matchedView)
.withView2(matchedViewIterator.next())
.withOtherAmbiguousViews(Iterators.toArray(matchedViewIterator, View.class))
.build();
} else {
matchedView = matchedViewIterator.next();
}
}
if (null == matchedView) {
List<View> adapterViews =
IterablesKt.filterToList(
breadthFirstViewTraversal(root), ViewMatchers.isAssignableFrom(AdapterView.class));
if (adapterViews.isEmpty()) {
throw new NoMatchingViewException.Builder()
.withViewMatcher(viewMatcher)
.withRootView(root)
.build();
}
String warning =
String.format(
Locale.ROOT,
"\n"
+ "If the target view is not part of the view hierarchy, you may need to use"
+ " Espresso.onData to load it from one of the following AdapterViews:%s",
StringJoinerKt.joinToString(adapterViews, "\n- "));
throw new NoMatchingViewException.Builder()
.withViewMatcher(viewMatcher)
.withRootView(root)
.withAdapterViews(adapterViews)
.withAdapterViewWarning(warning)
.build();
} else {
return matchedView;
}
}
}