CAGradientLayer 颜色渐变实现进度条

#import <UIKit/UIKit.h>



@interface TJGradientProgressView : UIView

/**

 *  进度值

 */

@property(nonatomic,assign) CGFloat progressValue;

/**

 *  开始动画

 */

- (void)startAnimating;

/**

 *  停止动画

 */

- (void)stopAnimating;



@end

//

//  TJGradientProgressView.m

//  TJGradientProgressViewDemo

//

//  Created by SNWF on 15/6/17.

//  Copyright (c) 2015年 SNWFMJ. All rights reserved.

//



#import "TJGradientProgressView.h"

@interface TJGradientProgressView ()

{

    CALayer *progressMaskLayer; //进度条蒙版layer图层

    

}

/**

 *  是否开始动画

 */

@property(nonatomic,assign) BOOL ISAnimating;

@end

@implementation TJGradientProgressView

@synthesize ISAnimating = _ISAnimating;

@synthesize progressValue = _progressValue;



- (instancetype)initWithFrame:(CGRect)frame

{

    if (self = [super initWithFrame:frame])

    {

        /**设置颜色值*/

        CAGradientLayer *gradientLayer = (id)[self layer];

        gradientLayer.startPoint = CGPointMake(0.0, 0.5);

        gradientLayer.endPoint = CGPointMake(1.0, 0.5);

        

        NSMutableArray *colorArray = [NSMutableArray array];

        for (NSInteger Hue = 0; Hue <= 360; Hue += 5) {

            UIColor *color = [UIColor colorWithHue:1.0*Hue/360.f

                                        saturation:1.0

                                        brightness:1.0

                                             alpha:1.0];

            [colorArray addObject:(id)color.CGColor];

        }

        gradientLayer.colors = [NSArray arrayWithArray:colorArray];

        

        progressMaskLayer = [CALayer layer];

        progressMaskLayer.frame = CGRectMake(0, 0, 0, frame.size.height);

        progressMaskLayer.backgroundColor = [UIColor blackColor].CGColor;

        gradientLayer.mask = progressMaskLayer;

        

    }

    return self;

}



- (void)setProgressValue:(CGFloat)progressValue

{

    _progressValue = MIN(1.0, fabs(progressValue));

    [self setNeedsLayout];

}



- (void)layoutSubviews

{

    CGRect maskRect = progressMaskLayer.frame;

    maskRect.size.width = CGRectGetWidth(self.bounds)*_progressValue;

    progressMaskLayer.frame = maskRect;

   



}

+ (Class)layerClass

{

    return [CAGradientLayer class];

}

- (NSArray *)shiftColors:(NSArray *)colors {

    

    NSMutableArray *mutable = [colors mutableCopy];

    id last = [mutable lastObject];

    [mutable removeLastObject];

    [mutable insertObject:last atIndex:0];

    return [NSArray arrayWithArray:mutable];

}



- (void)performAnimation

{

    CAGradientLayer *layer = (id)[self layer];

    NSArray *fromColors = [layer colors];

    NSArray *toColors = [self shiftColors:fromColors];

    [layer setColors:toColors];

    

    CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"colors"];

    [animation setFromValue:fromColors];

    [animation setToValue:toColors];

    [animation setDuration:0.08];

    [animation setRemovedOnCompletion:YES];

    [animation setFillMode:kCAFillModeForwards];

    [animation setTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear]];

    [animation setDelegate:self];

    [layer addAnimation:animation forKey:@"animationGradient"];

}

- (void)animationDidStop:(CAAnimation *)animation finished:(BOOL)flag {

    

    if (self.ISAnimating) {

        

        [self performAnimation];

    }

}



- (void)startAnimating {

    

    if (!self.ISAnimating)

    {

        

        _ISAnimating = YES;

        

        [self performAnimation];

    }

}



- (void)stopAnimating {

    

    if (self.ISAnimating) {

        

        _ISAnimating = NO;

    }

    

}











@end

//

//  ViewController.m

//  TJGradientProgressViewDemo

//

//  Created by SNWF on 15/6/17.

//  Copyright (c) 2015年 SNWFMJ. All rights reserved.

//



#import "ViewController.h"

#import "TJGradientProgressView.h"

@interface ViewController ()

{

    TJGradientProgressView *progressView;

}

@end



@implementation ViewController



- (void)viewDidLoad {

    [super viewDidLoad];

    CGRect frame = CGRectMake(0, 22.0f, CGRectGetWidth(self.view.bounds), 1.0f);

    progressView = [[TJGradientProgressView alloc] initWithFrame:frame];

    

    [self.view addSubview:progressView];

    [progressView startAnimating];

    [self simulateProgress];

    //[NSTimer scheduledTimerWithTimeInterval:1.f target:self selector:@selector(testAnimation) userInfo:nil repeats:YES];

    

  

}





- (void)testAnimation

{

    progressView.progressValue +=0.1;

    if (progressView.progressValue >=1.0f) {

        [progressView setProgressValue:0.1];

    }



}

- (void)simulateProgress {

    

    double delayInSeconds = 2.0;

    dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(delayInSeconds * NSEC_PER_SEC));

    dispatch_after(popTime, dispatch_get_main_queue(), ^(void){

        

        CGFloat increment = (arc4random() % 5) / 10.0f + 0.1;

        CGFloat progress  = progressView.progressValue + increment;

        [progressView setProgressValue:progress];

        if (progress < 1.0) {

            

            [self simulateProgress];

        }

    });

}



@end