Updating UI from Async Task, Publish Progress to UI

在android中系统不允許在非Main Thread更新UI。當我們在非主線程做了耗時操作後，需要去更新UI的時候，我們就需要使用Handler來執行更新操作。

大家都有面試的經驗，過程中曾經被問到執行序的問題，面試官問你：「確定UI真的一定不能在子執行緒更新嗎？為什麼？」，當時的回答感覺不夠深入。

There are two rules to Android's single-thread model: Don't block the UI thread. Don't access the Android UI toolkit from outside the UI thread.

Below you can see when and where to do you background task and after completion of long task you can update your UI using handler class.

There are multiple ways to update the screen periodically in an Android application. Here are five common approaches.

My question is, what is the most efficient way to update the UI thread continuously as a stop watch would need to do?

If you are doing some heavy task on Thread and you want to update some UI element (Edittext, Textview etc..) then you have to write that update UI code in ...

You can use runOnUiThread() method of activity to update UI from background thread. Or you can use a android Handler to achieve this.

Fundamentally, Handlers and Loopers is the base mechanism for communication between threads in Android OS, all other async tools that post ...

android asynchronously update UI | android update UI from thread | android asynchronous example We will learn how to asynchronously update ...