compat/src/main/java/androidx/core/os/HandlerCompat.java

/*
 * Copyright 2018 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.core.os;

import android.os.Handler;
import android.os.Message;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;

/**
 * Helper for accessing features in {@link Handler}.
 */
public final class HandlerCompat {
    /**
     * Causes the Runnable r to be added to the message queue, to be run
     * after the specified amount of time elapses.
     * The runnable will be run on the thread to which this handler
     * is attached.
     * <b>The time-base is {@link android.os.SystemClock#uptimeMillis}.</b>
     * Time spent in deep sleep will add an additional delay to execution.
     *
     * @param r The Runnable that will be executed.
     * @param token An instance which can be used to cancel {@code r} via
     *         {@link Handler#removeCallbacksAndMessages}.
     * @param delayMillis The delay (in milliseconds) until the Runnable
     *        will be executed.
     *
     * @return Returns true if the Runnable was successfully placed in to the
     *         message queue.  Returns false on failure, usually because the
     *         looper processing the message queue is exiting.  Note that a
     *         result of true does not mean the Runnable will be processed --
     *         if the looper is quit before the delivery time of the message
     *         occurs then the message will be dropped.
     *
     * @see Handler#postDelayed(Runnable, Object, long)
     */
    public static boolean postDelayed(@NonNull Handler handler, @NonNull Runnable r,
            @Nullable Object token, long delayMillis) {
        if (BuildCompat.isAtLeastP()) {
            return handler.postDelayed(r, token, delayMillis);
        }

        Message message = Message.obtain(handler, r);
        message.obj = token;
        return handler.sendMessageDelayed(message, delayMillis);
    }

    private HandlerCompat() {
    }
}