tracking the position of dragview

Question

Hello everyone

I put a dragview on an UIView, I hope when I drag the dragview, its superview (UIView) tracks the position of the dragview and moves itself to the position where to keep dragview at the original position on the UIView.

The codes show below:

#import <UIKit/UIKit.h>


@interface DragView : UIImageView {
    CGPoint startLocation;

}

@end

#import "DragView.h"


@implementation DragView


- (id)initWithFrame:(CGRect)frame {
    if (self = [super initWithFrame:frame]) {
        // Initialization code
    }
    return self;
}


- (void)drawRect:(CGRect)rect {
    // Drawing code
}

-(void) touchesBegan:(NSSet *)touches withEvent:(UIEvent*)event
{
    CGPoint pt=[[touches anyObject] locationInView:self];
    startLocation=pt;
    [[self superview] bringSubviewToFront:self];
}
-(void) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
    CGPoint pt=[[touches anyObject] locationInView:self];
    CGRect frame=[self frame];
    frame.origin.x+=pt.x-startLocation.x;
    frame.origin.y+=pt.y-startLocation.y;

    CGRect frame1=[[self superview] frame];//superview of the dragview
    frame1.origin.x+=frame.origin.x;    //tracks the postion of dragview
    frame1.origin.y+=frame.origin.y;
    [[self superview] setFrame: frame1 ]; //move to new position


    [self setFrame:frame];

}

my problem is that the UIView moved but lagged to the movement of the drageview(RED BLOCK).

Welcome any comment

Thanks

interdev