How to use drawRect to draw in a existing view?

Question

I\'m doing a GPS tracking app. Every time it receives a Latitude/Longitude it converts it to (x,y) coordinates and calls drawRect to draw a line between two (x,

Answer 1

What exactly to you mean by "old contents"? If you want to draw a line from your GPS data, you have to draw all points every time in the implementation of drawRect.