MainThreadAsyncHandler.java
/*
* Copyright 2019 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.camera.core.impl.utils;
import android.os.Handler;
import android.os.Looper;
import androidx.core.os.HandlerCompat;
/**
* Singleton instance of an async main thread {@link Handler}.
* @see HandlerCompat#createAsync(Looper)
*/
public final class MainThreadAsyncHandler {
private static volatile Handler sHandler;
/**
* Returns a main thread handler which marks all messages/runnables posted as async.
* @see HandlerCompat#createAsync(Looper)
*/
public static Handler getInstance() {
if (sHandler != null) {
return sHandler;
}
synchronized (MainThreadAsyncHandler.class) {
if (sHandler == null) {
sHandler = HandlerCompat.createAsync(Looper.getMainLooper());
}
}
return sHandler;
}
// Should not be instantiated
private MainThreadAsyncHandler() {}
}