iOS - 折叠动画 UISlider

Posted 2023-03-13

【中文标题】iOS - 折叠动画 UISlider

【英文标题】：iOS - Collapsing Animated UISlider

【发布时间】：2013-06-18 16:59:42

【问题描述】：

我想创建一个折叠动画 UISlider。基本上，滑块将调整缩略图的大小，直到它被触摸时，它会在更改时扩展为全尺寸。更改值并放开滑块后，滑块将折叠回原始大小（缩略图的大小）。

我尝试使用 touchesBegan 和 touchesEnd，但这并没有让我走得太远。

到目前为止，我已经继承了 UISlider 并覆盖了 beginTrackingWithTouch 和 endTrackingWithTouch。这段代码完成了折叠效果（当然没有动画），但拇指滑块不再改变。关于如何最好地做到这一点的任何想法？

#import "CollapsingUISlider.h"

@implementation CollapsingUISlider


/*-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event 
//self.frame = CGRectMake(self.frame.origin.x, self.frame.origin.y, self.frame.size.width       * 4.0f, self.frame.size.height);
[super touchesBegan:touches withEvent:event];

-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event 
//  self.frame = CGRectMake(self.frame.origin.x, self.frame.origin.y, self.frame.size.width * 0.25f, self.frame.size.height);
[super touchesEnded:touches withEvent:event];
*/
-(BOOL)beginTrackingWithTouch:(UITouch *)touch withEvent:(UIEvent *)event 
      self.frame = CGRectMake(self.frame.origin.x, self.frame.origin.y, 400,   self.frame.size.height);
      return YES;

-(void)endTrackingWithTouch:(UITouch*)touch withEvent:(UIEvent *)event 
     self.frame = CGRectMake(self.frame.origin.x, self.frame.origin.y, 20, self.frame.size.height);

-(BOOL) continueTrackingWithTouch:(UITouch *)touch withEvent:(UIEvent *)event 
    self.frame = CGRectMake(self.frame.origin.x, self.frame.origin.y, 400, self.frame.size.height);
    return self.tracking;

@end

【问题讨论】：

问题是当您开始触摸时，您已经开始与控件交互，这意味着它可能正在跟踪值的变化。如果您同时调整控件的大小，您会发现这不是一个好主意。也可能以奇怪的方式行事。

返回值（特别是self.tracking）可能有问题。我认为您可以通过更改子视图框架来更轻松、更安全地进行操作，否则布局将被破坏。

【参考方案1】：

我最终做了这样的事情：

 UIPanGestureRecognizer *panRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(move:)];
[panRecognizer setMinimumNumberOfTouches:1];
[panRecognizer setMaximumNumberOfTouches:1];
[platformView addGestureRecognizer:panRecognizer];

-(void)move:(id)sender 
[self.view bringSubviewToFront:[(UIPanGestureRecognizer*)sender view]];
CGPoint translatedPoint = [(UIPanGestureRecognizer*)sender translationInView:self.view];

if ([(UIPanGestureRecognizer*)sender state] == UIGestureRecognizerStateBegan) 
    firstX = [[sender view] center].x;
    firstY = [[sender view] center].y;


translatedPoint = CGPointMake(firstX, firstY+translatedPoint.y);
[[sender view] setCenter:translatedPoint];
if (platformView.center.y < platformCenter.y - offset) 
    platformView.center = CGPointMake(platformCenter.x,platformCenter.y-offset);
    ((UIPanGestureRecognizer*)sender).enabled = NO;
 else if (platformView.center.y > platformCenter.y) 
    platformView.center = CGPointMake(platformCenter.x,platformCenter.y);
    ((UIPanGestureRecognizer*)sender).enabled = NO;