content: /*
   * 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 androidx.test.espresso.Root;
  import java.util.List;
  
  /** Provides access to all root views in an application. */
  public interface ActiveRootLister {
  
    /**
     * Lists the active roots in an application at this moment.
     *
     * @return a list of all the active roots in the application.
     * @throws IllegalStateException if invoked from a thread besides the main thread.
     */
    public List<Root> listActiveRoots();
  }
  