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POHow To Draw line on touch event?
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  1. POHow To Draw line on touch event?
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    copied!<p>Hey i m beginner of objective C Please Help me </p> <p>i make following code but not work.....</p> <pre><code>-(void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event { UITouch *touch = [touches anyObject]; if ([touch view] == self.view) { CGPoint location = [touch locationInView:self.view]; loc1 = location; CGContextMoveToPoint(context, location.x, location.y); NSLog(@"x:%d y:%d At Touch Begain", loc1.x, loc1.y); } } - (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event { UITouch *touch = [touches anyObject]; if ([touch view] == self.view) { CGPoint location = [touch locationInView:self.view]; CGContextMoveToPoint(context, loc1.x, loc1.y); NSLog(@"x:%d y:%d At Touch Move", loc1.x, loc1.y); CGContextAddLineToPoint(context, location.x, location.y); NSLog(@"x:%d y:%d", location.x, location.y); } } </code></pre> <p>i declare contex in viewdidload method and also try to declare in touch event but not work...</p> <p>My app Log file look like...</p> <blockquote> <p>x:0 y:1079934976 At Touch Move Thu Jan 13 11:20:05 .local DragDrop[536] : </p> <p>CGContextAddLineToPoint: invalid context 0x0 2011-01-13 11:20:05.149 DragDrop[536:207] x:0 y:1079902208 Thu Jan 13 11:20:05 .local DragDrop[536] :</p> <p>CGContextSetRGBStrokeColor: invalid context 0x0 Thu Jan 13 11:20:05 .local DragDrop[536] :</p> <p>CGContextDrawPath: invalid context 0x0 Thu Jan 13 11:20:05 .local DragDrop[536] : </p> <p>CGContextMoveToPoint: invalid context 0x0 2011-01-13 11:20:05.199 DragDrop[536:207] x:0 y:1079934976 At Touch Move Thu Jan 13 11:20:05 .local DragDrop[536] : </p> <p>CGContextAddLineToPoint: invalid context 0x0 2011-01-13 11:20:05.200 DragDrop[536:207] x:0 y:1079885824</p> </blockquote>
 

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