从另一个线程在主线程中运行代码 [英] Running code in main thread from another thread

问题描述

在一个 android 服务中，我创建了线程来执行一些后台任务.

In an android service I have created thread(s) for doing some background task.

我有一个线程需要在主线程的消息队列上发布某些任务的情况，例如一个 Runnable.

I have a situation where a thread needs to post certain task on main thread's message queue, for example a Runnable.

有没有办法获取主线程的 Handler 并将 Message/Runnable 从我的另一个线程发送给它?

Is there a way to get Handler of the main thread and post Message/Runnable to it from my other thread?

推荐答案

注意:这个答案受到了如此多的关注，我需要更新它.自从发布原始答案以来，@dzeikei 的评论几乎与原始答案一样受到关注.所以这里有两种可能的解决方案:

NOTE: This answer has gotten so much attention, that I need to update it. Since the original answer was posted, the comment from @dzeikei has gotten almost as much attention as the original answer. So here are 2 possible solutions:

1.如果您的后台线程引用了 Context 对象:

1. If your background thread has a reference to a Context object:

确保您的后台工作线程可以访问上下文对象(可以是应用程序上下文或服务上下文).然后在后台工作线程中执行此操作:

Make sure that your background worker threads have access to a Context object (can be the Application context or the Service context). Then just do this in the background worker thread:

// Get a handler that can be used to post to the main thread
Handler mainHandler = new Handler(context.getMainLooper());

Runnable myRunnable = new Runnable() {
    @Override 
    public void run() {....} // This is your code
};
mainHandler.post(myRunnable);

2.如果您的后台线程没有(或不需要)Context 对象

2. If your background thread does not have (or need) a Context object

(由@dzeikei 建议):

(suggested by @dzeikei):

// Get a handler that can be used to post to the main thread
Handler mainHandler = new Handler(Looper.getMainLooper());

Runnable myRunnable = new Runnable() {
    @Override 
    public void run() {....} // This is your code
};
mainHandler.post(myRunnable);

这篇关于从另一个线程在主线程中运行代码的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！