Question

我创建了一个绘图应用程序。由于我在大图像上使用绘图，我也需要滚动，但是当我实现滚动时，绘图不再起作用。

我认为绘图和滚动之间的触摸事件存在冲突。

我想用两根手指滚动并用一根手指画画，但我找不到如何实现它。如果有人能帮助我解决这个问题，我感激不尽。

-(void)viewDidLayoutSubviews
{
    scroller.scrollEnabled=YES;
    scroller.contentSize=temp.frame.size;
    toggledrawandscroll=false;


}
- (IBAction)changescrollstatues:(id)sender {
   if(toggledrawandscroll){
    //if draw is enable,disable it
    toggledrawandscroll =false;
    scroller.scrollEnabled=YES;
    scroller.canCancelContentTouches=YES;
    scroller.contentSize=temp.frame.size;
}
else{

    toggledrawandscroll =true;
    scroller.scrollEnabled=NO;
    scroller.canCancelContentTouches=NO;

}
}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
        mouseSwiped = NO;
        UITouch *touch = [touches anyObject];
        lastPoint = [touch locationInView:self.view];
        }

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
        //initial setting for touch point
        mouseSwiped = YES;
        UITouch *touch = [touches anyObject];
        CGPoint currentPoint = [touch locationInView:self.view];

        //set the concext
        UIGraphicsBeginImageContext(self.view.frame.size);
        [temp.image drawInRect:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)];
        CGContextMoveToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);


        CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), currentPoint.x, currentPoint.y);
        //drawing setting
        CGContextSetLineCap(UIGraphicsGetCurrentContext(), kCGLineCapRound);
        CGContextSetLineWidth(UIGraphicsGetCurrentContext(), 1);
        CGContextSetRGBStrokeColor(UIGraphicsGetCurrentContext(),red, green, blue, 1);
        CGContextSetLineWidth(UIGraphicsGetCurrentContext(), 1);
        CGContextSetBlendMode(UIGraphicsGetCurrentContext(),kCGBlendModeNormal);
        CGContextStrokePath(UIGraphicsGetCurrentContext());
        temp.image = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();
        lastPoint = currentPoint;

}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
           if(!mouseSwiped) {

            //initial seting
            UIGraphicsBeginImageContext(self.view.frame.size);
            [temp.image drawInRect:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)];
            CGContextSetLineCap(UIGraphicsGetCurrentContext(), kCGLineCapRound);
            CGContextSetLineWidth(UIGraphicsGetCurrentContext(), brush);
            CGContextSetRGBStrokeColor(UIGraphicsGetCurrentContext(), red, green, blue, opacity);
            CGContextMoveToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);
            CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);
            CGContextStrokePath(UIGraphicsGetCurrentContext());
            CGContextFlush(UIGraphicsGetCurrentContext());
            temp.image = UIGraphicsGetImageFromCurrentImageContext();
            UIGraphicsEndImageContext();
        }

}

Answer 1

所以看起来你有一个切换来启用滚动？如果是这种情况，您的 changesscrollstatues 方法永远不会启用滚动，并且永远不会将您的布尔值设置为 YES 。您的滚动条始终处于启用状态，因此触摸事件不会被捕获。

同时滚动和绘图

1 个答案: