移动一个UIImageView在Y轴

Question

我工作的一个应用程序，我想在只有Y轴移动一个UIImage，而不是在X轴，这里就是我所做的到现在

 
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event 
{ 
stretchPoint = [[touches anyObject]locationInView:self.view]; 
arrowImage.center = stretchPoint; 

} 

上面的代码中移动在这两个轴的箭头图像， stretchPoint是一个CGPoint的实例，我的应用程序是肖像模式，任何人都可以给我一个基本的想法，如何做到这一点，因为arrowImage是UIImageView的一个实例。

Answer 1

这应该很好地工作：

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event { 
     UITouch *touch = [touches anyObject]; 

     CGPoint currentPoint = [touch locationInView:self.view]; 
     currentPoint.x = arrowImage.center.x; 

     arrowImage.center = currentPoint; 
    } 

Answer 2

我不知道因为没有测试过，但你可以实现这样的事情：

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event 
{ 
    UITouch *touch = [touches anyObject]; 
    CGPoint currentPoint = [touch locationInView:self.view]; 
    currentPoint.y = 20; 
} 

Answer 3

喜欢的东西：

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event 
{ 
    stretchPoint = [[touches anyObject] locationInView:self.view]; 
    arrowImage.frame = CGPointMake(arrowImage.origin.x, 
            stretchPoint.y, 
            arrowImage.size.width, 
            arrowImage.size.height); 

} 

Answer 4

继承UIImage并实现以下代码

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event 
{ 
    UITouch *touch = [touches anyObject]; 
    CGPoint currentPoint = [touch locationInView:[self superview]]; 


    CGPoint newCenter = CGPointMake(self.center.x, currentPoint.y); 
    self.center = newCenter; 


}