项目里下完单之后要悬浮红包，类似饿了吗那种。
做完了记录下：
@implementation SearchResultViewController
{
UIButton * moveRedPacket;
}
#pragma mark 红包
//创建移动红包的UI
-(void)CreatMoveRedPacketUI{
UIPanGestureRecognizer * panTouch = [[UIPanGestureRecognizer alloc]initWithTarget:self action:@selector(handlePan:)];
if (moveRedPacket==nil) {
moveRedPacket = [[UIButton alloc]initWithFrame:CGRectMake(ScreenWidth-120, ScreenHeight-120, 80, 85)];
}
[moveRedPacket setBackgroundImage:[UIImage imageNamed:@"red"] forState:UIControlStateNormal];
[moveRedPacket addTarget:self action:@selector(ClickRedPacket:) forControlEvents:UIControlEventTouchUpInside];
[moveRedPacket addGestureRecognizer:panTouch];
[self.view addSubview:moveRedPacket];
}
/**
* 处理拖动手势
*
* @param recognizer 拖动手势识别器对象实例
*/
- (void)handlePan:(UIPanGestureRecognizer *)recognizer {
//视图前置操作
[recognizer.view.superview bringSubviewToFront:recognizer.view];
CGPoint center = recognizer.view.center;
CGFloat cornerRadius = recognizer.view.frame.size.width / 2;
CGPoint translation = [recognizer translationInView:self.view];
//NSLog(@"%@", NSStringFromCGPoint(translation));
recognizer.view.center = CGPointMake(center.x translation.x, center.y translation.y);
[recognizer setTranslation:CGPointZero inView:self.view];
if (recognizer.state == UIGestureRecognizerStateEnded) {
//计算速度向量的长度，当他小于200时，滑行会很短
CGPoint velocity = [recognizer velocityInView:self.view];
CGFloat magnitude = sqrtf((velocity.x * velocity.x) (velocity.y * velocity.y));
CGFloat slideMult = magnitude / 200;
//NSLog(@"magnitude: %f, slideMult: %f", magnitude, slideMult); //e.g. 397.973175, slideMult: 1.989866
//基于速度和速度因素计算一个终点
float slideFactor = 0.1 * slideMult;
CGPoint finalPoint = CGPointMake(center.x (velocity.x * slideFactor),
center.y (velocity.y * slideFactor));
//限制最小［cornerRadius］和最大边界值［self.view.bounds.size.width - cornerRadius］，以免拖动出屏幕界限
finalPoint.x = MIN(MAX(finalPoint.x, cornerRadius),
self.view.bounds.size.width - cornerRadius);
finalPoint.y = MIN(MAX(finalPoint.y, cornerRadius),
self.view.bounds.size.height - cornerRadius);
//使用 UIView 动画使 view 滑行到终点
[UIView animateWithDuration:slideFactor*2
delay:0
options:UIViewAnimationOptionCurveEaseOut
animations:^{
recognizer.view.center = finalPoint;
}
completion:nil];
}
}
