iOS拖拽功能
XXJcanbethebest 人气:0在APP界面中，把资讯等功能设置为悬浮的Button并且能够让用户自己拖拽调整位置很常用。这里实现一下上述的功能，我们先看一下效果图
这里给UIButton的拖拽的范围进行了设定，超过了这个区域则强行结束拖拽。
我们知道UIButton是自带手势事件的，但我们不选择使其自带的手势事件来响应拖拽，其原因为自带的手势不好得到和控制拖拽的状态。我们创建一个 UIPanGestureRecognizer 添加给UIButton
- (void)viewDidLoad {
[super viewDidLoad];
Width=[UIScreen mainScreen].bounds.size.width;
Height=[UIScreen mainScreen].bounds.size.height;
UIButton *btn=[[UIButton alloc]initWithFrame:CGRectMake(10, 200, 60, 60)];
btn.backgroundColor=[UIColor blueColor];
[btn setTitle:@"B" forState:UIControlStateNormal];
//UIPanGestureRecognizer手势
UIPanGestureRecognizer *pan=[[UIPanGestureRecognizer alloc]initWithTarget:self action:@selector(movingBtn:)];
[btn addGestureRecognizer:pan];
[self.view addSubview:btn];
}然后我们实现 movingBtn
-(void)movingBtn:(UIPanGestureRecognizer *)recognizer{
//得到拖拽的UIButton
UIButton *button = (UIButton *)recognizer.view;
//得到拖拽的偏移量
CGPoint translation = [recognizer translationInView:button];
//对拖拽事件的状态进行判断 也就是选择自定义手势的原因
if(recognizer.state == UIGestureRecognizerStateBegan){
}else if(recognizer.state == UIGestureRecognizerStateChanged){
//实时设置button的center、recognizer
button.center = CGPointMake(button.center.x + translation.x, button.center.y + translation.y);
[recognizer setTranslation:CGPointZero inView:button];
//对button的位置进行判断，超出范围则强行使拖拽事件结束
//这个范围可以自己自定义
if(button.center.x <= 40 || button.center.x>=Width-40 || button.center.y <=100 || button.center.y >=Height-100){
[recognizer setState:UIGestureRecognizerStateEnded];
}
}else if(recognizer.state == UIGestureRecognizerStateEnded){
//得到结束时button的center
//根据center 判断应该的X和Y
CGFloat newX=button.center.x;
if(button.center.x <=Width/2) newX=40;
else if(button.center.x >=Width/2) newX=Width-40;
CGFloat newY=button.center.y;
if(button.center.y <=100) newY=100;
else if(button.center.y >=Height-100) newY=Height-100;
button.center = CGPointMake(newX, newY);
[recognizer setTranslation:CGPointZero inView:button];
}
}至此 我们就实现了可拖拽的UIButton
加载全部内容