How to invalidate() a View from another thread?

Question

I've got a couple of Views that are updated once a second by a Timer task. They can't invalidate() themselves because "only the original thread that created a view hierarchy can touch its views".

There is a function called runOnUiThread for this, but I need an Activity to run it.

How can I solve this problem?

Edit: Is this what postInvalidate() is for? How guaranteed am I that the invalidation and update will happen soon (if the UI thread isn't busy)?

Answer 1

1)

Is this what postInvalidate() is for?

Yes

According to the Docs

Use this to invalidate the View from a non-UI thread.

invalidate() is for updating Views on the UI Thread

2)

How guaranteed am I that the invalidation and update will happen soon (if the UI thread isn't busy)?

Also from that same part of the docs

Cause an invalidate to happen on a subsequent cycle through the event loop

So I guess this depends on your definition of "soon". As the docs say it should happen on the next event loop