iOS - WaveLoadingView

RXWaveLoadingView.h

#import <UIKit/UIKit.h>

@interface RXWaveLoadingView : UIView

@property (nonatomic, assign) NSInteger numberOfWaves;
@property (nonatomic, assign) CGSize waveSize;
@property (nonatomic, assign) CGFloat waveSpacing;
@property (nonatomic, assign) CGFloat waveDuration;
@property (nonatomic, strong) UIColor *waveColor;

- (void)startAnimating;
- (void)stopAnimating;

@end

RXWaveLoadingView.m

#import "RXWaveLoadingView.h"

@implementation RXWaveLoadingView

static NSString *kRXWaveLoadingView = @"RXWaveLoadingView";

- (instancetype)init {
    self = [super init];
    if (self) {
        _numberOfWaves = 5;
        _waveSize = CGSizeMake(10, 40);
        _waveSpacing = 3;
        _waveColor = [UIColor lightGrayColor];
        _waveDuration = 0.1;
    }
    return self;
}

- (CAAnimation*)addAnimateWithDelay:(CGFloat)delay {
    CABasicAnimation* animation = [CABasicAnimation animationWithKeyPath:@"transform.rotation.x"];
    animation.repeatCount = MAXFLOAT;
    animation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear];
    animation.fromValue = [NSNumber numberWithFloat:M_PI / _numberOfWaves];
    animation.toValue = [NSNumber numberWithFloat:M_PI + M_PI / _numberOfWaves];
    animation.duration = _numberOfWaves * _waveDuration;
    animation.beginTime = CACurrentMediaTime() + delay;
    return animation;
}

- (void)startAnimating {
    [self stopAnimating];

    for (int i = 0; i < _numberOfWaves; i++) {
        CGRect frame = CGRectMake(i * (_waveSize.width + _waveSpacing), 0, _waveSize.width, _waveSize.height);
        UIView *waveView = [[UIView alloc] initWithFrame:frame];
        [waveView setBackgroundColor:_waveColor];
        [waveView.layer addAnimation:[self addAnimateWithDelay:i * _waveDuration] forKey:kRXWaveLoadingView];
        [self addSubview:waveView];
    }
    self.hidden = NO;
}

- (void)stopAnimating {
    if (self.subviews.count) {
        [self.subviews makeObjectsPerformSelector:@selector(removeFromSuperview)];
    }
    self.hidden = YES;
}

@end