雷达扫描动画

#import "ViewController.h"
#import "RadarView.h"

@interface ViewController ()
@property (nonatomic, strong) RadarView *radarView;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];

    self.view.backgroundColor = [UIColor blackColor];
    self.radarView = [[RadarView alloc]initWithFrame:CGRectMake(0, 0, 370, 370)];
    self.radarView.center = self.view.center;
    [self.view addSubview:self.radarView];
    [self.radarView radarScan];
    // Do any additional setup after loading the view, typically from a nib.
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end

RadarView.h  文件

//
//  RadarView.h
//  ScanAnimation
//

#import <UIKit/UIKit.h>
#import "RadarIndicationView.h"
@interface RadarView : UIView

@property (nonatomic, strong)RadarIndicationView *radarIndicationView;

-(void) radarScan;

@end

RadarView.m  文件

//
//  RadarView.m
//  ScanAnimation
//

#import "RadarView.h"

@implementation RadarView

-(instancetype)initWithFrame:(CGRect)frame{
    if ([super initWithFrame:frame]) {
        [self addSubview:self.radarIndicationView];
    }
    return self;
}

-(void) drawRect:(CGRect)rect{

    [super drawRect:rect];
    CGContextRef context = UIGraphicsGetCurrentContext();
    [self drawCircle:context];

}

- (RadarIndicationView *)radarIndicationView{

    if (!_radarIndicationView) {
        _radarIndicationView = [[RadarIndicationView alloc]initWithFrame:CGRectMake(0, 0, 340, CGRectGetHeight(self.frame))];
        _radarIndicationView.center = self.center;
    }

    return _radarIndicationView;

}

- (void)drawCircle:(CGContextRef )context
{
    //将坐标轴移动到视图中心
    CGContextTranslateCTM(context, CGRectGetWidth(self.frame)/2.0, CGRectGetHeight(self.frame)/2.0);

    CGContextSetStrokeColorWithColor(context, [UIColor greenColor].CGColor);
    CGContextSetLineWidth(context, 2);

    //画圆弧
    for (int i = 0; i <4; i++) {
        CGContextMoveToPoint(context, 50+i*40, 0);
        CGContextAddArc(context, 0, 0, 50+i*40, 0,  M_PI*2, 0);
    }
    CGContextStrokePath(context);

    //画十字坐标
    CGContextMoveToPoint(context, -170, 0);
    CGContextAddLineToPoint(context, 170, 0);

    CGContextMoveToPoint(context, 0, -170);
    CGContextAddLineToPoint(context, 0, 170);

    CGContextStrokePath(context);

}

//开始扫描
-(void) radarScan{

    [self.radarIndicationView start];

}

RadarIndicationView.h  文件

//
//  RadarIndicationView.h
//  ScanAnimation
//

#import <UIKit/UIKit.h>

@interface RadarIndicationView : UIView

-(void) start;
-(void) stop;

@end

RadarIndicationView.m 文件

//
//  RadarIndicationView.m
//  ScanAnimation
//

#import "RadarIndicationView.h"

@implementation RadarIndicationView

-(instancetype)initWithFrame:(CGRect)frame{
    if ([super initWithFrame:frame]) {
        self.backgroundColor = [UIColor clearColor];
    }
    return self;

}

-(void) drawRect:(CGRect)rect{
    [super drawRect:rect];
    CGContextRef context = UIGraphicsGetCurrentContext();
    [self drawArc:context];
}

//画大扇形
-(void) drawArc:(CGContextRef) context{

    //将坐标轴移到视图中心
    CGContextTranslateCTM(context, CGRectGetWidth(self.frame)/2.0, CGRectGetHeight(self.frame)/2.0);
    //设置扇形半径

    CGFloat radius = CGRectGetWidth(self.frame)/2.0;
    CGContextSetLineWidth(context, 0.1);
    CGContextSetStrokeColorWithColor(context, [UIColor whiteColor].CGColor);

    CGFloat single = M_PI/180/2.0;//画图时每次旋转的度数
    CGFloat colorAlpha = M_PI_2/90/2.0;
    CGFloat x = 0.0;
    for (int i = 0; i < 90*2; i++) {
        //画小扇形
        CGContextMoveToPoint(context, 0, 0);
        CGContextAddArc(context, 0, 0, radius, 0, -single, 1);

        //设置填充颜色以及透明度
        x = x + colorAlpha;
        CGFloat alpha = sin(1-x);
        UIColor *color = [UIColor colorWithRed:41/255 green:253/255 blue:47/255 alpha:alpha];

        [color setFill];

        CGContextFillPath(context);
        CGContextDrawPath(context, kCGPathFillStroke);//绘制路径

        //逆时针旋转坐标
        CGContextRotateCTM(context, -single);

    }

}

- (void) start{
    [self setNeedsDisplay];

    CABasicAnimation *rotationAnimation;
    rotationAnimation = [CABasicAnimation animationWithKeyPath:@"transform.rotation.z"];
    rotationAnimation.toValue = @(2*M_PI);
    rotationAnimation.duration = 360/60;
    rotationAnimation.repeatCount = NSIntegerMax;
    [self.layer addAnimation:rotationAnimation forKey:@"rotationAnimation"];

}

-(void)stop{
    [self.layer removeAnimationForKey:@"rotationAnimation"];
}
-(void)rectangularCoordinates{

    //画x
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextSetLineWidth(context, 1);
    CGContextSetStrokeColorWithColor(context, [UIColor greenColor].CGColor);
    CGContextMoveToPoint(context, 0, 0);
    CGContextAddLineToPoint(context, 150, 0);
    CGContextStrokePath(context);

    CGContextMoveToPoint(context, 150, 0);
    CGContextSetStrokeColorWithColor(context, [UIColor redColor].CGColor);
    CGContextAddLineToPoint(context, 140, 5);
    CGContextMoveToPoint(context, 150, 0);
    CGContextAddLineToPoint(context, 140, -5);
    CGContextStrokePath(context);

    //画y
    CGContextSetStrokeColorWithColor(context, [UIColor greenColor].CGColor);
    CGContextMoveToPoint(context, 0, 0);
    CGContextAddLineToPoint(context, 0, 150);
    CGContextAddLineToPoint(context, 5, 140);
    CGContextMoveToPoint(context, -5, 150);
    CGContextAddLineToPoint(context, -5, 140);
    CGContextStrokePath(context);

}