仿qq黏性demo

////  AceCuteView.m//  LayerDemo1////  Created by jackren on 16/3/9.//  Copyright © 2016年 jackren. All rights reserved.//#import "AceCuteView.h"@interface AceCuteView (){        CGFloat r1; // backView    CGFloat r2; // frontView    CGFloat x1;    CGFloat y1;    CGFloat x2;    CGFloat y2;    CGFloat centerDistance;    CGFloat cosDigree;    CGFloat sinDigree;        CGPoint pointA; //A    CGPoint pointB; //B    CGPoint pointD; //D    CGPoint pointC; //C    CGPoint pointO; //O    CGPoint pointP; //P}@property UIView *backView;@property UIView *frontView;@property UILabel *label;@property CAShapeLayer *BezierLayer;@end@implementation AceCuteView-(instancetype)initWithFrame:(CGRect)frame{    self = [super initWithFrame:frame];        if (self) {                [self setUp];        [self addGesture];                _BezierLayer = [CAShapeLayer layer];        _BezierLayer.lineWidth = 1;        _BezierLayer.fillColor = _bgColor.CGColor;        [self.layer insertSublayer:_BezierLayer atIndex:0];            }        return self;}-(void)setUp{    _bgColor = [UIColor redColor];    CGFloat DefaultSize = CGRectGetHeight(self.frame);        _backView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, DefaultSize, DefaultSize)];    _backView.backgroundColor = self.bgColor;    _backView.layer.cornerRadius = CGRectGetHeight(_backView.frame)/2;    _backView.center = CGPointMake(self.frame.size.width/2, self.frame.size.height/2);    [self addSubview:_backView];            _frontView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, CGRectGetWidth(self.frame), DefaultSize)];    _frontView.backgroundColor = self.bgColor;    _frontView.layer.cornerRadius = DefaultSize/2;    [self addSubview:_frontView];            _label = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, CGRectGetWidth(self.frame), DefaultSize)];    _label.backgroundColor = [UIColor clearColor];    _label.textColor = [UIColor whiteColor];    _label.textAlignment = NSTextAlignmentCenter;    _label.layer.cornerRadius = DefaultSize/2;        _label.text = @"13";    if (_bubbleText.length>0) {        _label.text = _bubbleText;    }    [self.frontView addSubview:_label];}-(void)addGesture{    UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(doHandlePanAction:)];    [_frontView addGestureRecognizer:pan];}- (void)doHandlePanAction:(UIPanGestureRecognizer *)paramSender{    CGPoint point = [paramSender translationInView:self];    paramSender.view.center = CGPointMake(paramSender.view.center.x + point.x, paramSender.view.center.y + point.y);    [paramSender setTranslation:CGPointMake(0, 0) inView:self];        //粘度设置    if (_viscosity == 0) {        _viscosity = 50;    }    if (_viscosity < 30) {        _viscosity = 30;    }    if (_viscosity > 90) {        _viscosity = 90;    }            [self addBezierPathLayer:_BezierLayer];            if (paramSender.state == UIGestureRecognizerStateBegan) {        _backView.hidden = NO;    }            if (paramSender.state == UIGestureRecognizerStateChanged) {        if (centerDistance>_viscosity) {            _BezierLayer.path = nil;            _backView.hidden = YES;        } else {            _backView.hidden = NO;        }    }            if (paramSender.state == UIGestureRecognizerStateEnded || paramSender.state ==UIGestureRecognizerStateCancelled || paramSender.state == UIGestureRecognizerStateFailed) {                //距离50以内没问题        if (centerDistance < _viscosity) {            _BezierLayer.path = nil;            _backView.hidden = YES;            [UIView animateWithDuration:0.3 delay:0.0f usingSpringWithDamping:0.2f initialSpringVelocity:0.6f options:UIViewAnimationOptionCurveEaseInOut animations:^{                paramSender.view.center = _backView.center;            } completion:nil];        } else {            //距离50外            [self removeFromSuperview];        }            }    }-(void)addBezierPathLayer:(CAShapeLayer *)layer{    x1 = _backView.center.x;    y1 = _backView.center.y;    x2 = _frontView.center.x;    y2 = _frontView.center.y;        centerDistance = sqrtf((x2-x1)*(x2-x1)+(y2-y1)*(y2-y1));                CGFloat size = self.frame.size.height-centerDistance*0.2;    _backView.frame = CGRectMake(0, 0, size, size);    _backView.center = CGPointMake(x1, y1);    _backView.layer.cornerRadius = CGRectGetWidth(_backView.frame)/2;        #if 1        r1 = _backView.frame.size.height/2;    r2 = _frontView.frame.size.height/2;        if (centerDistance == 0) {        cosDigree = 1;        sinDigree = 0;    }else{        cosDigree = (y2-y1)/centerDistance;        sinDigree = (x2-x1)/centerDistance;    }        float m = 2;    pointA = CGPointMake(x1-r1*cosDigree, y1+r1*sinDigree);  // A    pointB = CGPointMake(x1+r1*cosDigree, y1-r1*sinDigree); // B    pointD = CGPointMake(x2-r2*cosDigree, y2+r2*sinDigree); // D    pointC = CGPointMake(x2+r2*cosDigree, y2-r2*sinDigree);// C    pointO = CGPointMake(pointA.x + (centerDistance / m)*sinDigree, pointA.y + (centerDistance / m)*cosDigree);    pointP = CGPointMake(pointB.x + (centerDistance / m)*sinDigree, pointB.y + (centerDistance / m)*cosDigree);            UIBezierPath *path = [UIBezierPath bezierPath];            //B→C  D→A  需要贝赛尔曲线    [path moveToPoint:pointA];    [path addQuadCurveToPoint:pointD controlPoint:pointO];    [path addLineToPoint:pointC];    [path addQuadCurveToPoint:pointB controlPoint:pointP];    [path moveToPoint:pointA];        layer.path = path.CGPath;    #endif}@end

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