android - Activity.runOnUiThread(runnable action) 和 Handler.post() 有什么区别？

Question

在 android 中使用 Activity.runOnUiThread 或 Handler.post(runnable action) 有什么区别/优点/缺点？

Answer 1

Activity.runOnUiThread，顾名思义，将在当前负责 UI 的线程中执行 Runnable。因此，如果您有一个 CPU 密集型任务，它可能会使 UI 在短时间内无响应。相反，Handler 为您提供了一种创建线程、运行一些代码并在完成后通知 UI 的方法(即 Handler.sendMessage)。

Handler 的文档比我能更好地说明这一点:

When a process is created for your application, its main thread is dedicated to running a message queue that takes care of managing the top-level application objects (activities, broadcast receivers, etc) and any windows they create. You can create your own threads, and communicate back with the main application thread through a Handler. This is done by calling the same post or sendMessage methods as before, but from your new thread. The given Runnable or Message will than be scheduled in the Handler's message queue and processed when appropriate.