Question

I have a UIImageView, above which I have multiple markers. All the markers are movable, i.e. when I touch a marker, I can move it all around the screen.
Problem: if I touch a marker, and I begin to move it to another place, if I cross another marker, the old marker is left in place of the new one, and I continue to move the new one. And I want to evade this somehow.

Thanks for the answer.

Answer 1

What are your markers? If they are UIView instances then I would suggest watching for touch events on them instead of the image view and then deal with the Z order while dragging.

I would also pay attention to touch up vs. touch moved to help with the issue of your stops and starts.

If they are not UIView instances then the issue sounds like it is with your touch down vs moved. i.e. you should keep track of what marker was touched on the down event and then ignore any events that hit another marker that are not down events until you get an up.

If these suggestions are not helpful then describing how you built your view structure would help.

Z-Order

When you receive a touch down event on a marker I would move it to the top of the z order of views within the parent. Then will allow it to visually slide over the other markers.