线程执行工具类

在Android中经常会用到多线程开发，最简单的做法是new一个Thread去执行，这种写法如果多的话，线程的创建和管理开销也是非常大的，在代码中lint也会有警告提示。现在介绍一个简洁的线程管理工具类。
代码如下：

import android.os.Handler;
import android.os.Looper;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class TaskService {

    private static volatile TaskService sTaskService;
    private final ExecutorService mExecutorService;
    private final Handler mHandler;


    private TaskService(){
        mExecutorService = Executors.newCachedThreadPool();
        mHandler = new Handler(Looper.getMainLooper());
    }

    public static TaskService getInstance(){
        if(sTaskService==null){
            synchronized (TaskService.class){
                if(sTaskService==null){
                    sTaskService = new TaskService();
                }
            }
        }
        return sTaskService;
    }

    public void doBackTask(Runnable runnable){
        if(runnable!=null){
            mExecutorService.submit(runnable);
        }
    }

    public void doBackTaskDelay(final Runnable runnable, long delay){
        if(runnable!=null){
            if(delay<0){
                delay = 0;
            }
            mHandler.postDelayed(new Runnable() {
                @Override
                public void run() {
                    mExecutorService.submit(runnable);
                }
            },delay);
        }
    }

    public void postTaskInMain(Runnable runnable){
        if(runnable!=null){
            mHandler.post(runnable);
        }
    }

    public Handler getHandler(){
        return mHandler;
    }
}

该工具类采用单例的实现方式，线程执行是用Executors.newCachedThreadPool()方式实现线程复用。
使用方式：

1. 开线程执行任务：

 TaskService.getInstance().doBackTask(new Runnable())

2. 切换到主线程执行任务：

TaskService.getInstance().postTaskInMain(new Runnable());

3. 延时执行多线程任务：

TaskService.getInstance().doBackTaskDelay(new Runnable(),3000);