Correct approach to update UI in Android

I'm new to Android stuff. Currently I have someone else code in my hand and I'm trying to understand the functionality. Whoever wrote the code, used Handler and messages in it. For example, if a button is clicked, onClick listener is called which then posts a message to handler. Inside the handler there is a switch case statement which calls different methods based on a data passed in Message what attribute.

My question is, is this a correct approach or we should just call our method directly in the onClick handler.

As i understand, handler should be used to post a message to the main UI thread, from some other thread (worker 开发者_如何学Cthread which pulls data from server).

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You are correct. OnClick should already be running in the UI thread and thus there is no need to use a handler. The only times I have used a Handler is for posting callbacks from an OpenGL or timer/worker thread OR when I need a message to be handled in the future.

[update] I will add that if the handler is somehow posting to some non-GUI thread then that might make sense under very particular circumstances but the most common case is for code called from onClick to execute in the GUI thread.

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if your method inside button onclick(),is a long running process ,say for a example getting data from server,so it is better to use that method in separate thread.

when the method process is completed ,using handler post message and the proceed further.