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Re: While loop, sleep [message #60264 is a reply to message #60262]

Fri, 27 October 2023 21:50

Klugier
Messages: 1077
Registered: September 2012
Location: Poland, Kraków

Senior Contributor

Hello,

I agree with zsolt. SetTimeCallback is the way to go in your case. Currently, I am working on expanding our GUI tutorial about exemplary usage of that feature.

Here is the code:

#include <CtrlLib/CtrlLib.h>

using namespace Upp;

struct MyAppWindow : TopWindow {
	Rect  rect;
	Color color;
	
	MyAppWindow() {
		Zoomable().SetRect(0, 0, 200, 200);
		
		RandomizeRect();
		SetTimeCallback(-2000, [=] { OnTimer(); });
	}
	
	~MyAppWindow() {
		KillTimeCallback();
	}
	
	void Paint(Draw& w) override {
		Size sz = GetSize();
		
		w.DrawRect(sz, White());
		w.DrawRect(rect, color);
	}
	
	void OnTimer() {
		RandomizeRect();
		Refresh();
	}
	
	void RandomizeRect() {
		Size sz = GetSize();
		
		int length = 50;
		int x = Random() % (sz.cx - length);
		int y = Random() % (sz.cy - length);
		
		rect = Rect(x, y, x + length, y + length);
		color = Color(Random() % 255, Random() % 255, Random() % 255);
	}
};

GUI_APP_MAIN
{
	MyAppWindow().Run();
}

The first parameter in this case mean interval in milliseconds. If it is less than zero it means that it will be repeated infinite number of times. If the number is positive it will be executed only once.

SetTimeCallback(-2000, [=] { OnTimer(); });

In above example, the method OnTimer() in Ctrl will be executed once per 2 seconds until cancellation. Cancellation can be done by calling KillTimeCallback().

Moreover with SetTimeCallback you shouldn't observe any UI freezes or something like that.

Regards,
Klugier

U++ - one framework to rule them all.

[Updated on: Fri, 27 October 2023 21:58]

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