Android Question What's the preferred way to do a wait?

Troberg said:

Occasionally, especially in some GUI cases, one wants to wait a short while before continuing. For example:

Do something
Show a message
Wait 3 seconds
Show another message
Wait 3 seconds
Clear messages

In this case, it's messages, but it's not limited to that.

What is the preferred method om implementing such a wait. Sure, I could use a timer, but that would either lead to a very awkward partitioning of the code (especially if large piles of variables are needed both before and after the wait) or to the use of a DoEvents-loop, which will drain the battery.

So, what is the proper way of doing this?

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Personally, I would use the Threading library. First, because it's what Google recommends (in their Google Play Services library, for example, all disk and network operations are done in the background). Second, because the timer solution is just horrible for me: reading a flag constantly to know its state instead of raising an event (calling another function) when this state changes is something that I would avoid at all costs in an event-driven language (except for semaphores, but the use of a semaphore means we are using background threads).

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Dim thread1 As Thread
thread1.Initialise("")
thread1.Sleep(1000)

Rick Harris said:

Here is an example of unpredictable code. If I use this routine in the Activity_Create sub to create a delay (to hold a logo on the screen for 2 seconds), everything is fine:

B4X:

    If FirstTime Then             
      WTicks1 = DateTime.Now
      Do While WTicks2 < (WTicks1+2000)
        WTicks2 = DateTime.Now
        DoEvents
      Loop
End If

But if I change this under Activity_Create by:

B4X:

WACHT1(2000)

and:

B4X:

Sub WACHT1(Duur1 As Long)           'Duur1 in msec!
    WTicks1 = DateTime.Now
    Do While WTicks2 < (WTicks1+Duur1)
      WTicks2 = DateTime.Now
      DoEvents
    Loop
End Sub

then strangely enough a ListView will not open later on in my app when I press the button that holds the Listview1.visible = True code. Unexplainable! It must have something to do with the use of DoEvents. Any thoughts?

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