iOS实现雷达扫描效果的方法步骤

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#import  @interface LTIndicatiorView : UIView@property(nonatomic,strong)UIColor *color;@property(nonatomic,assign)float repeatCount;@property(nonatomic,strong)UIColor *borderColor;@property(nonatomic,assign)float borderWidth;@end @interface LTRadarView : UIView@property(nonatomic,strong)UIColor *color;@property(nonatomic,strong)UIColor *borderColor;@property(nonatomic,assign)float borderWidth;@property(nonatomic,assign)int pulsingCount;@property(nonatomic,assign)float duration;@property(nonatomic,assign)float repeatCount;@property(nonatomic,strong)CALayer *pulsingLayer;  @end

.m文件

////  LTRadarView.m//  raderScan////  Created by mac on 17/2/5.//  Copyright © 2017年 mac. All rights reserved.// #import "LTRadarView.h" #define Angel 15 @interface LTRadarButton : UIButton @end @implementation LTRadarButton - (void)removeFromSuperview{    [UIView beginAnimations:@"" context:nil];    [UIView setAnimationDuration:0.5];    self.transform = CGAffineTransformMakeScale(0.2, 0.2);    self.alpha = 0;    [UIView setAnimationDidStopSelector:@selector(callSuperRemoveFromSuperview)];    [UIView commitAnimations]; } - (void)callSuperRemoveFromSuperview{    [super removeFromSuperview];} - (id)initWithFrame:(CGRect)frame{    self = [super initWithFrame:frame];    self.alpha = 0;    return self;} - (void)didMoveToWindow{    [super didMoveToWindow];     self.transform = CGAffineTransformMakeScale(0.2, 0.2);    if (self.window) {        [UIView animateWithDuration:0.5 animations:^{            self.transform = CGAffineTransformIdentity;            self.alpha = 1;        }];    }    }   @end  @implementation LTIndicatiorView - (id)initWithFrame:(CGRect)frame{    if (self = [super initWithFrame:frame]) {        _color = [UIColor greenColor];        _repeatCount = HUGE_VALF;        _borderColor = [UIColor redColor];        _borderWidth = 1.0f;    }    return self;}   // Only override drawRect: if you perform custom drawing. // An empty implementation adversely affects performance during animation. - (void)drawRect:(CGRect)rect { // Drawing code          self.backgroundColor = [UIColor whiteColor];     [super drawRect:rect];     self.layer.cornerRadius = self.frame.size.height/2.0f;     self.clipsToBounds = YES;     self.layer.borderColor = [UIColor clearColor].CGColor;     self.layer.borderWidth = 50;     self.layer.masksToBounds = YES;               CGContextRef context = UIGraphicsGetCurrentContext();     for (int i = 0; i < Angel; i++) {         CGFloat alpha = (float)i /(float)600;         CGColorRef shadowColor = [[UIColor greenColor] colorWithAlphaComponent:alpha].CGColor;//计算扇形填充颜色         CGContextSetFillColorWithColor(context, shadowColor);         CGContextMoveToPoint(context, self.center.x, self.center.y);//指定员心         CGFloat startAngle =  (-Angel+i+1.15)/Angel*(float)M_PI;         CGFloat endAngle = (-Angel+i-1.15)/Angel*(float)M_PI;//         NSLog(@"startAngle = %f endAngle = %f ,alpha = %f",startAngle,endAngle,alpha);         CGContextAddArc(context, self.center.x, self.center.y, self.frame.size.height/2.0f,0, 25, 1);//画一个扇形         CGContextClosePath(context);                  CGContextDrawPath(context, kCGPathFill);//绘制扇形      }          CGContextSetLineWidth(context, 1);//扫描线宽度     CGContextSetStrokeColorWithColor(context, [_color colorWithAlphaComponent:1].CGColor);//扫描线颜色     CGContextMoveToPoint(context, self.center.x, self.center.y);     CGContextAddLineToPoint(context, self.frame.size.height, self.center.y);     CGContextStrokePath(context);          CGContextSetRGBStrokeColor(context,255/255.0, 255/255.0, 255/255.0, 0.1);//最外面圆颜色     CGContextSetLineWidth(context, 10);//线宽度     CGContextAddArc(context, self.center.x, self.center.y, self.frame.size.height/2.0, 0, 2*M_PI, 1);//添加一个圆     CGContextDrawPath(context, kCGPathStroke);//绘制路径          CGContextStrokePath(context);//显示绘制               //扫描动画     CABasicAnimation *rotateAnimation = [CABasicAnimation animation];     rotateAnimation.keyPath = @"transform.rotation.z";     rotateAnimation.toValue = @(2*M_PI);     rotateAnimation.duration = 3;     rotateAnimation.removedOnCompletion = NO;     rotateAnimation.repeatCount = _repeatCount;         [self.layer addAnimation:rotateAnimation forKey:@"rotate_layer"]; }  @end  @implementation LTRadarView{    NSMutableArray *items;}  - (id)initWithFrame:(CGRect)frame{    if (self = [super initWithFrame:frame]) {                items = [NSMutableArray array];        _color = [UIColor redColor];              _borderColor = [UIColor greenColor];        _pulsingCount = 3;        _duration = 3;        _repeatCount = HUGE_VALF;        _borderWidth = 3.0f;    }    return self;} // Only override drawRect: if you perform custom drawing.// An empty implementation adversely affects performance during animation.- (void)drawRect:(CGRect)rect {    // Drawing code    [super drawRect:rect];        self.layer.cornerRadius = self.frame.size.height/2;    self.clipsToBounds = YES;    self.layer.borderColor = [UIColor clearColor].CGColor;    self.layer.borderColor = [UIColor clearColor].CGColor;    self.layer.borderWidth = 50;    self.layer.masksToBounds = YES;        CGContextRef ctx = UIGraphicsGetCurrentContext();    CGContextSetRGBFillColor(ctx, 0/255.0, 0/255.0, 0/255.0, 1);//圆颜色    CGContextSetLineWidth(ctx, 1);//宽度    CGContextAddArc(ctx, self.center.x, self.center.y, self.frame.size.height/2, 0, 2*M_PI, 1);//添加一个圆    CGContextDrawPath(ctx, kCGPathStroke);//绘制    CGContextStrokePath(ctx);//显示        CALayer *animationLayer = [CALayer layer];    animationLayer.frame = self.layer.frame;    for (int i = 0; i < _pulsingCount; i++) {                CALayer *pulsingLayer = [CALayer layer];        pulsingLayer.frame = CGRectMake(0, 0, rect.size.width, rect.size.height);        pulsingLayer.borderColor = [UIColor clearColor].CGColor;        pulsingLayer.borderWidth = 1;        pulsingLayer.cornerRadius = rect.size.height/2;        pulsingLayer.backgroundColor = [UIColor redColor].CGColor;                CAAnimationGroup *animationGroup = [CAAnimationGroup animation];        animationGroup.fillMode = kCAFillModeBoth;        animationGroup.beginTime = CACurrentMediaTime() + (float) i * _duration / _pulsingCount;        animationGroup.duration = _duration;        animationGroup.repeatCount = HUGE_VALF;        animationGroup.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear];        animationGroup.autoreverses = NO;        animationGroup.delegate = self;        animationGroup.removedOnCompletion = NO;                CABasicAnimation *scaleAnimation = [CABasicAnimation animation];        scaleAnimation.keyPath = @"transform.scale";        scaleAnimation.removedOnCompletion = NO;        scaleAnimation.fromValue = @(0.0f);        scaleAnimation.toValue = @1.0f;        scaleAnimation.autoreverses = NO;                        CAKeyframeAnimation *opacityAnimation = [CAKeyframeAnimation animation];        opacityAnimation.keyPath = @"opacity";        opacityAnimation.values = @[@1.0,@0.75,@0.5,@0.25,@0.0];        opacityAnimation.keyTimes = @[@0.0,@0.25,@0.5,@0.75,@1];        opacityAnimation.autoreverses = NO;        opacityAnimation.removedOnCompletion = NO;                animationGroup.animations = @[scaleAnimation,opacityAnimation];        [pulsingLayer addAnimation:animationGroup forKey:@"pulsing"];                [animationLayer addSublayer:pulsingLayer];    }        [self.layer addSublayer:animationLayer];        [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(addOrReplaceItem) userInfo:nil repeats:YES];}  - (void)animation:(CALayer *)layer{    CAAnimationGroup *animationGroup = [CAAnimationGroup animation];    animationGroup.fillMode = kCAFillModeBoth;    animationGroup.beginTime = CACurrentMediaTime() + 1 * _duration / _pulsingCount;    animationGroup.duration = _duration;    animationGroup.repeatCount = HUGE_VALF;    animationGroup.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear];    animationGroup.autoreverses = NO;    animationGroup.delegate = self;    animationGroup.removedOnCompletion = NO;        CABasicAnimation *scaleAnimation = [CABasicAnimation animation];    scaleAnimation.keyPath = @"transform.scale";    scaleAnimation.removedOnCompletion = NO;    scaleAnimation.fromValue = @(0.0f);    scaleAnimation.toValue = @1.0f;    scaleAnimation.autoreverses = NO;            CAKeyframeAnimation *opacityAnimation = [CAKeyframeAnimation animation];    opacityAnimation.keyPath = @"opacity";    opacityAnimation.values = @[@1.0,@0.75,@0.5,@0.25,@0.0];    opacityAnimation.keyTimes = @[@0.0,@0.25,@0.5,@0.75,@1];    opacityAnimation.autoreverses = NO;    opacityAnimation.removedOnCompletion = NO;        animationGroup.animations = @[scaleAnimation,opacityAnimation];    [layer addAnimation:animationGroup forKey:@"pulsing"];        } #define RandomColor [UIColor colorWithRed:arc4random_uniform(256)/255.0 green:arc4random_uniform(256)/255.0 blue:arc4random_uniform(256)/255.0 alpha:1.0]/* 生成一个在圆里面的坐标 生成的坐标要围绕中心的绿点（圆心），让我们重新翻开数学课本，看看高中数学对三角函数的定义： 在一个平面直角坐标系中，以原点为圆心，1 为半径画一个圆，这个圆交 x 轴于 A 点。以 O 为旋转中心，将 A 点逆时针旋转一定的角度α至 B 点，设此时 B 点的坐标是(x,y)，那么此时 y 的值就叫做α的正弦，记作 sinα；此时 x 的值就叫做α的余弦，记作 cosα；y 与 x 的比值 y/x 就叫做α的正切，记作 tanα。  任意角三角函数 正弦sinθ=y/r, 余弦cosθ=x/r,正切tanθ=y/x,余切cotθ=x/y,正割secθ=r/x,余割cscθ=r/y 锐角三角函数 正弦sinA=a/c, 余弦cosA=b/c,正切tanA=a/b,余切cotA=b/a,正割secA=c/b,余割cscA=c/a  还有一个很重要的公式：圆的参数方程：以点O（a，b）为圆心，以r为半径的圆的参数方程是 x=a+r*cosθ, y=b+r*sinθ, （其中θ为参数） 到这里为止，思路就清晰了，以下是generateCenterPointInRadar的方法实现： */ - (CGPoint)generateCenterPointInRadar{    float  angle = arc4random() % 360;//随机一个角度    float radius = arc4random() % (int)((self.bounds.size.width - 44)/2);//随机一个半径， 这里减去44是因为要把这个view显示在圆里面，如果不减44，则有可能会显示在圓外面    double x = cos(angle) * radius;//计算随机出现的一个角度的x坐标 x=a+r*cosθ r = radius, θ = angle ,a ＝ 圆心的x坐标    double y = sin(angle) * radius;//计算随机出现的一个角度的y坐标 y=b+r*sinθ r = radius, θ = angle ,b ＝ 圆心的y坐标    return CGPointMake(x + self.bounds.size.width / 2, y + self.bounds.size.height / 2);//x y 分别加个圆心的坐标即self.center.x.y} - (void)addOrReplaceItem{    int maxCount = 10;        LTRadarButton *radarButton = [LTRadarButton buttonWithType:UIButtonTypeCustom];    radarButton.frame = CGRectMake(0, 0, 44, 44);    radarButton.backgroundColor = RandomColor;    radarButton.layer.cornerRadius = 44/2;         do {        CGPoint center = [self generateCenterPointInRadar];        radarButton.center = CGPointMake(center.x, center.y);    } while ([self itemFrameIntersectsInOtherItem:radarButton.frame]);             [self addSubview:radarButton];    [items addObject:radarButton];        if (items.count > maxCount)    {        UIView * view = [items firstObject];        [view removeFromSuperview];        [items removeObject:view];    }}  /* 我们现在在生成每个item的center的时候，没有和已有的item进行比较，这是一个比较耗性能的操作，如果你的itemSize过大，maxCount过多，这甚至能导致死循环，如果是那样的话，你可能在对itemSize以及maxCount做出限制的同时，也对循环的数量也进行控制，如果在生成一个item的center的时候，进行了过多的循环，就可以视为进入死循环了，在这种情况下，你只能重新计算已有的centers。这里不考虑这种极端情况，因为目前的itemSize和maxCount的配合，不会出现死循环。 我们添加一个itemFrameIntersectsInOtherItem私有方法来判断是否和之前生成的center有了重叠： */- (BOOL)itemFrameIntersectsInOtherItem:(CGRect)frame{    for (UIView *item in items)    {        if (CGRectIntersectsRect(item.frame, frame))        {            return YES;        }    }    return NO;}

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