src/com/android/settings/utils/ThreadUtils.java

/*
 * Copyright (C) 2016 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 com.android.settings.utils;

import android.os.Looper;

public class ThreadUtils {
    private static volatile Thread sMainThread;

    /**
     * Returns true if the current thread is the UI thread.
     */
    public static boolean isMainThread() {
        if (sMainThread == null) {
            sMainThread = Looper.getMainLooper().getThread();
        }
        return Thread.currentThread() == sMainThread;
    }

    /**
     * Checks that the current thread is the UI thread. Otherwise throws an exception.
     */
    public static void ensureMainThread() {
        if (!isMainThread()) {
            throw new RuntimeException("Must be called on the UI thread");
        }
    }

}