iOS实现雷达扫描效果

#import <UIKit/UIKit.h>
 
@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

//
//  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;
}