Android Question B4A Version of VB flush keyboard buffer?

almontgreen · Oct 30, 2013

During a sub execution I'd like to ignore any keys that are pressed or mouse clicks, etc. At the end of the sub if I could clear all pending keyboard activity or mouse activity, that would be great!

I'm not sure the best way to do it. Any help would be awesome. I'm hoping there is a simple way.

Erel · Oct 30, 2013

There is no such buffer in Android.

Which mouse clicks? Do you mean touches?
What are you doing in this sub?

almontgreen · Oct 30, 2013

Erel said:
There is no such buffer in Android.

Which mouse clicks? Do you mean touches?
What are you doing in this sub?

I am using Android Mini PC and use key presses to activate video and image manipulation. A child or impatient user will press many keys in an attempt to manipulate an image presentation (panning, rotation, zooming, etc.) or simply "play" with the system. These key presses build up, as keys can be pressed faster than the images can be loaded and displayed until the app exits, probably due to some memory issue.

I was looking for an "easy" fix. Short of that, I was thinking I could re-direct the key press activity to somewhere else while images are being loaded. A different view?

Erel · Oct 30, 2013

Call ProgressDialogShow and hide it when the sub completes. You will also need to call DoEvents inside the loop to make it spin.

almontgreen · Oct 30, 2013

Erel said:
Call ProgressDialogShow and hide it when the sub completes. You will also need to call DoEvents inside the loop to make it spin.

It would appear that calling ProgressDialogShow does sort of eat the keyboard presses - unfortunately, I don't want the screen dimmed or to show a spinning icon. I'll probably look into a different view to send the activities while the sub is working...

I've not had the greatest experience using DoEvents. Since I'm trying to use as much cache memory as possible to hold as many images in memory as I can, I don't have a lot left over to use for different tasks. Somehow DoEvents impacts memory and leads to an untimely application exit in some cases.

Informatix · Oct 30, 2013

Why don't you simply ignore the keys when a flag is raised? I mean: when you start your task, you set a flag to true. While this flag is set, you ignore all key strokes (you only return true in the event handler). When the task ends, you set the flag to false to reenable the key handling.

almontgreen · Oct 30, 2013

Informatix said:
Why don't you simply ignore the keys when a flag is raised? I mean: when you start your task, you set a flag to true. While this flag is set, you ignore all key strokes (you only return true in the event handler). When the task ends, you set the flag to false to reenable the key handling.

That's the way I thought it would work (I do return true in the event handler). But, evidently the keys that are pressed during the sub stay in the cue and try to get processed after the sub completes, causing the sub to get triggered over and over until something happens with memory and the app exits.

Informatix · Oct 30, 2013

Do you mean that your task is blocking the app while it runs (thus, no event can be processed in the meanwhile)? In this case, you should really use DoEvents to handle the waiting messages. I can't see why DoEvents would eat memory. You should trace what subs you enter to be sure that you run only what's needed. The memory loss comes from somewhere in your code.

almontgreen · Oct 30, 2013

Informatix said:
Do you mean that your task is blocking the app while it runs (thus, no event can be processed in the meanwhile)? In this case, you should really use DoEvents to handle the waiting messages. I can't see why DoEvents would eat memory. You should trace what subs you enter to be sure that you run only what's needed. The memory loss comes from somewhere in your code.

Yes, I don't want anything else to happen during the sub processing and DoEvents seems like a way to eat the keyboard presses - I'll do some testing, this makes sense. Thanks!

almontgreen · Nov 1, 2013

RESOLVED!

I used a Timer Sub to increment a Global variable (i+1) each time the timer sub fires and I set a starting timer value (timerval=i+1000) at the beginning of the Sub Activity_Keypress. At the end of the Sub Activity_Keypress I set the timerval to 1 and within a timer sub I checked to see if the timerval was less than i. If that condition was true then I set a variable to process Keypresses again. Works great.

By the way, I did learn that if you send too many DoEvents to quickly that the program exits.

Android Question B4A Version of VB flush keyboard buffer?

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