iOS實現雷達掃描效果

#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;//計算扇形填充顏色
         CGContextSetFillColorWithColor(context, shadowColor);
         CGContextMoveToPoint(context, self.center.x, self.center.y);//指定員心
         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);//畫一個扇形
         CGContextClosePath(context);
         
         CGContextDrawPath(context, kCGPathFill);//繪制扇形
 
     }
     
     CGContextSetLineWidth(context, 1);//掃描線寬度
     CGContextSetStrokeColorWithColor(context, [_color colorWithAlphaComponent:1].CGColor);//掃描線顏色
     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);//最外面圓顏色
     CGContextSetLineWidth(context, 10);//線寬度
     CGContextAddArc(context, self.center.x, self.center.y, self.frame.size.height/2.0, 0, 2*M_PI, 1);//添加一個圓
     CGContextDrawPath(context, kCGPathStroke);//繪制路徑
     
     CGContextStrokePath(context);//顯示繪制
     
     
     //掃描動畫
     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);//圓顏色
    CGContextSetLineWidth(ctx, 1);//寬度
    CGContextAddArc(ctx, self.center.x, self.center.y, self.frame.size.height/2, 0, 2*M_PI, 1);//添加一個圓
    CGContextDrawPath(ctx, kCGPathStroke);//繪制
    CGContextStrokePath(ctx);//顯示
    
    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]
/*
 生成一個在圓裡面的坐標
 生成的坐標要圍繞中心的綠點（圓心），讓我們重新翻開數學課本，看看高中數學對三角函數的定義：
 在一個平面直角坐標系中，以原點為圓心，1 為半徑畫一個圓，這個圓交 x 軸於 A 點。以 O 為旋轉中心，將 A 點逆時針旋轉一定的角度α至 B 點，設此時 B 點的坐標是(x,y)，那麼此時 y 的值就叫做α的正弦，記作 sinα；此時 x 的值就叫做α的餘弦，記作 cosα；y 與 x 的比值 y/x 就叫做α的正切，記作 tanα。
 
 任意角三角函數 正弦sinθ=y/r, 餘弦cosθ=x/r,正切tanθ=y/x,餘切cotθ=x/y,正割secθ=r/x,餘割cscθ=r/y
 銳角三角函數 正弦sinA=a/c, 餘弦cosA=b/c,正切tanA=a/b,餘切cotA=b/a,正割secA=c/b,餘割cscA=c/a
 
 還有一個很重要的公式：圓的參數方程：以點O（a，b）為圓心，以r為半徑的圓的參數方程是 x=a+r*cosθ, y=b+r*sinθ, （其中θ為參數）
 到這裡為止，思路就清晰瞭，以下是generateCenterPointInRadar的方法實現：
 */
 
- (CGPoint)generateCenterPointInRadar
{
    float  angle = arc4random() % 360;//隨機一個角度
    float radius = arc4random() % (int)((self.bounds.size.width - 44)/2);//隨機一個半徑， 這裡減去44是因為要把這個view顯示在圓裡面，如果不減44，則有可能會顯示在圓外面
    double x = cos(angle) * radius;//計算隨機出現的一個角度的x坐標 x=a+r*cosθ r = radius, θ = angle ,a ＝ 圓心的x坐標
    double y = sin(angle) * radius;//計算隨機出現的一個角度的y坐標 y=b+r*sinθ r = radius, θ = angle ,b ＝ 圓心的y坐標
    return CGPointMake(x + self.bounds.size.width / 2, y + self.bounds.size.height / 2);//x y 分別加個圓心的坐標即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];
    }
}
 
 
/*
 我們現在在生成每個item的center的時候，沒有和已有的item進行比較，這是一個比較耗性能的操作，如果你的itemSize過大，maxCount過多，這甚至能導致死循環，如果是那樣的話，你可能在對itemSize以及maxCount做出限制的同時，也對循環的數量也進行控制，如果在生成一個item的center的時候，進行瞭過多的循環，就可以視為進入死循環瞭，在這種情況下，你隻能重新計算已有的centers。這裡不考慮這種極端情況，因為目前的itemSize和maxCount的配合，不會出現死循環。
 我們添加一個itemFrameIntersectsInOtherItem私有方法來判斷是否和之前生成的center有瞭重疊：
 */
- (BOOL)itemFrameIntersectsInOtherItem:(CGRect)frame
{
    for (UIView *item in items)
    {
        if (CGRectIntersectsRect(item.frame, frame))
        {
            return YES;
        }
    }
    return NO;
}