core/java/android/app/FragmentContainer.java

/*
 * Copyright (C) 2015 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 android.app;

import android.annotation.IdRes;
import android.annotation.Nullable;
import android.view.View;

/**
 * Callbacks to a {@link Fragment}'s container.
 */
public abstract class FragmentContainer {
    /**
     * Return the view with the given resource ID. May return {@code null} if the
     * view is not a child of this container.
     */
    @Nullable
    public abstract View onFindViewById(@IdRes int id);

    /**
     * Return {@code true} if the container holds any view.
     */
    public abstract boolean onHasView();
}