How to Delay Hits on Android Code

Have you ever received the requirement that you want this view to display this page for 2 seconds and then go to the new page or display items apart at a given time? How to do this? It takes a delay or delay. Yes, horse.

So how many ways is there to delay on Android?

Compare 3 easy-to-understand hit methods with code samples

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1️⃣ Handler. PostDelayed.

The first method we've used since Java is super classic. 😆

Handler is a class of Android to help manage sending and processing messages on Thread queues. It works with Looper to receive and manage messages coming in loop.

Usually we create a Handler on Main Thread first and use postDelayed () to do some work after a certain period of time. This is to call doSomething () after a delay of 1000 milliseconds or 1 second.

Private val handler = Handler (Looper.getMainLooper ())

Handler.postDelayed ({doSomething ()}, 1000L)

The advantage is that it's easy to use and doesn't require any other libraries. It fits the task of running on Main Thread, but this one needs to be careful with memory leaks, because Handler still refers to the Activity or Fragment that we use to call Handler even after it's closed.

So don't forget to call the handler. removeCallbacksAndMessages (null) after use. I'll find that I'm not warning and the app is stale.

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2️⃣ View. PostDelayed.

It is a delay using the View that we want to suit the delay associated with the View directly.

The principle works and looks like Handler.postDelayed (), but we don't have to build Handler ourselves, because Android has already done it for us.

For example, we have a view called myView. The requirement says that we do not show this view after two seconds.

MyView. PostDelayed ({

MyView. Visibility (View. GONE)

}, 2000L)

The precaution is that although it is convenient, if the View is removed from the screen, our code may not work, so we will use this method to ensure that the View is still present before the delay ends.

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3️⃣ Coroutine and delay.

We're already Kotlin Android Developer, right? 😂

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So it takes Coroutine. It can use lifecycleScope.launch with delay (), which makes our code look very organized and easy to read.

LifecycleScope. Launch {

delay (1000L)

Something ()

}

Advantages Of course, the code is easy to read. It has to deplay 1 second first and then do something (). And when you use the Lifecycle-bound lifecycle of Activity, it will cancel when Activity is destroyed. You don't have to create a handler and delete it again.

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What methods do friends use? Or there are other postures, comment.

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