iphone - 在 y 轴上移动 UIImageView

Question

我正在开发一个应用程序，我只想在 Y 轴上移动 UIImage，而不是在 X 轴上，这就是我到目前为止所做的

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

}

上面的代码是在两个轴上移动箭头图像，stretchPoint 是 CGPoint 的一个实例，我的应用程序处于纵向模式，谁能给我一个基本的想法如何做到这一点，因为箭头图像是 UIImageView 的一个实例。

Answer 1

这应该可以正常工作：

 - (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

子类化 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;


}

Answer 3

我不确定是否没有测试，但你可以实现这样的东西：

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

Answer 4

就像是：

- (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);

}