Indication for “graphics complete”

Issue Type

[X] Question

Description and/or steps/code to reproduce the problem

@monsieurtanuki

Is there some way to know for sure if the graphics engine in osmdroid is completely done? If there are numerous overlays, the update may take a while. And I am not allowed to change the underlying data in between, as this could lead to an Exception.

The drawing process is triggered with mapView.invalidate() but when does it finish?

Environment

If it’s a bug, version(s) of android this affects:

All

Version of osmdroid the issue relates to:

6.1.11

[mikebravoyes]

@monsieurtanuki You were right: It had nothing to do with the display refresh. The problem was the following: There is a data set of geographical coordinates, which are translated into one or more Polylines for the map. This data set can be manipulated by two asynchronous threads, which may interfere with each other. To avoid that, I introduced a Semaphore, which is initialized at the start of the app.

public static Semaphore mutex = new Semaphore(1);

Then, in the two competing threads, they block each other with:

try {
	mutex.acquire();
	// prepare the data set with geographical coordinates
	...
	// generate Polylines from data set
	...
	mapView.invalidate();
} catch (InterruptedException e) {
	e.printStackTrace();
} finally {
	mutex.release();
}

And everything works without any problems. Thanks for your support!

[mikebravoyes]

@monsieurtanuki OK, I will make some tests accordingly and let you know…