在y轴上移动UIImageView

Question

我正在开发应用程序，我只想在Y轴上移动UIImage，而不要在Xaxis上移动，这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 = stretchPoint;

}

上面的代码在两个轴上都移动了arrowImage，stretchPoint是CGPoint的一个实例，我的应用程序处于纵向模式，任何人都可以给我一个基本的想法，因为arrowImage是UIImageView的一个实例。

Answer 1

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 2

这应该工作正常：

 - (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 3

我不确定还没有测试过，但是您可以执行以下操作：

- (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);

}