how to flash a point

You should remove the Do While loop and use a timer instead.

it works OK with a timer. Thank you

thedesolatesoul said:

You should remove the Do While loop and use a timer instead.

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It works fine with the timer. I do not very well why the "Do while" didnt work but many thanks for your fast answer.

it runs too fast

Ben said:

It works fine with the timer. I do not very well why the "Do while" didnt work but many thanks for your fast answer.

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Maybe it would have worked by adding a DoEvents inside the Do...While loop. But I dont like keeping the thread busy all the time, so I prefer Timers.

Ben said:

I do not very well why the "Do while" didnt work but many thanks for your fast answer.

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Because, like Windows and just about every other GUI, the Android GUI is single threaded and event driven and drawing the UI is done by putting messages in a message queue and processing them in a message loop. Android runs your message loop when your code has returned from any event Sub. If you sit in a loop in your Sub no messages can be processed so the GUI never gets updated.

If you call DoEvents in a loop the DoEvents method runs a message loop to process any GUI messages and in this case the GUI will be updated.

You should avoid writing code that waits for any time at all. If you do and if you wait for too long Android detects it and force closes your application.