Update a portion UIView
- by Brett
Hi;
I'm using -setNeedsDisplayinRect to update only a part of my UIView. However, all of my drawing done previously to calling this method is erased.
Here is my code in the UIView subclass:
-(void)drawRect:(CGRect)rect{
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetRGBFillColor(context, r, g, b, 1);
CGContextSetRGBStrokeColor(context, r, g, b, 1);
CGRect arect = CGRectMake(x,y,1,1);
CGContextFillRect(context, arect);
NSLog(@"drawing");
}
and in the view controller:
-(void)drawView{
drawingView = [[DrawingView alloc]init];
x=10;
y=10;
r=0;
g=0;
b=0;
[drawingView setNeedsDisplayInRect:CGRectMake(x, y, 1, 1)];
x=20;
y=20;
r=0;
g=0;
b=0;
[drawingView setNeedsDisplayInRect:CGRectMake(x, y, 1, 1)];
}
I end up with a screen where there is only one pixel at 20,20. Any help with this is so much appreciated. I am a beginner with XCode and am trying to complete a class project asap.
