UI定制 - 跑马灯（文本） - 低头捡石頭

UI定制 - 跑马灯（文本）

跑马灯

1 - 代码封装

// - JTSlideShadowAnimation.h

 1 #import <UIKit/UIKit.h>
 2 @interface JTSlideShadowAnimation : NSObject <CAAnimationDelegate>
 3 
 4 @property (strong, nonatomic) UIView *animatedView;
 5 @property (strong, nonatomic) UIColor *shadowBackgroundColor;
 6 @property (strong, nonatomic) UIColor *shadowForegroundColor;
 7 @property (assign, nonatomic) CGFloat shadowWidth;
 8 @property (assign, nonatomic) CGFloat repeatCount;
 9 @property (assign, nonatomic) NSTimeInterval duration;
10 
11 - (void)start;// 开启
12 - (void)stop; // 停止
13 
14 @end

// - JTSlideShadowAnimation.m

 1 #import "JTSlideShadowAnimation.h"
 2 
 3 @interface JTSlideShadowAnimation(){
 4     CABasicAnimation *currentAnimation;
 5 }
 6 
 7 @end
 8 
 9 @implementation JTSlideShadowAnimation
10 
11 - (id)init{
12     self = [super init];
13     if(!self){
14         return nil;
15     }
16     
17     [self commonInit];
18     return self;
19 }
20 
21 - (void)commonInit{
22     
23     self.shadowBackgroundColor = [UIColor colorWithWhite:1 alpha:.6];
24     self.shadowForegroundColor = [UIColor whiteColor];
25     self.shadowWidth = 30;
26     self.repeatCount = HUGE_VALF;
27     self.duration = 2.0;
28 }
29 
30 - (void)start{
31     if(!self.animatedView){
32         NSLog(@"JTSlideShadowAnimation no view to animate");
33         return;
34     }
35     [self stop];
36     
37     CAGradientLayer *gradientMask = [CAGradientLayer layer];
38     gradientMask.frame = self.animatedView.bounds;
39     CGFloat gradientSize = self.shadowWidth / self.animatedView.frame.size.width;
40     
41     NSArray *startLocations = @[@0,[NSNumber numberWithFloat:(gradientSize / 2.)],[NSNumber numberWithFloat:gradientSize]];
42     NSArray *endLocations = @[[NSNumber numberWithFloat:(1. - gradientSize)],[NSNumber numberWithFloat:(1. - (gradientSize / 2.))],@1];
43     
44     gradientMask.colors = @[(id)self.shadowBackgroundColor.CGColor,(id)self.shadowForegroundColor.CGColor,(id)self.shadowBackgroundColor.CGColor];
45 
46     gradientMask.locations = startLocations;
47     gradientMask.startPoint = CGPointMake(0 - (gradientSize * 2), .5);
48     gradientMask.endPoint = CGPointMake(1 + gradientSize, .5);
49     
50     self.animatedView.layer.mask = gradientMask;
51     currentAnimation = [CABasicAnimation animationWithKeyPath:@"locations"];
52     currentAnimation.fromValue = startLocations;
53     currentAnimation.toValue = endLocations;
54     currentAnimation.repeatCount = self.repeatCount;
55     currentAnimation.duration  = self.duration;
56     currentAnimation.delegate = self;
57     
58     [gradientMask addAnimation:currentAnimation forKey:@"JTSlideShadowAnimation"];
59 }
60 
61 - (void)stop{
62 
63     if(self.animatedView && self.animatedView.layer.mask){
64         [self.animatedView.layer.mask removeAnimationForKey:@"JTSlideShadowAnimation"];
65         self.animatedView.layer.mask = nil;
66         currentAnimation = nil;
67     }
68 }
69 
70 - (void)animationDidStop:(CAAnimation *)anim finished:(BOOL)finished{
71     if(anim == currentAnimation){
72         [self stop];
73     }
74 }
75 
76 @end

2 - 代码示例：如何使用

// - ViewController.m

 1 #import "ViewController.h"
 2 #import "JTSlideShadowAnimation.h"
 3 @interface ViewController ()
 4 
 5 @end
 6 
 7 @implementation ViewController
 8 
 9 - (void)viewDidLoad {
10     [super viewDidLoad];
11     self.view.backgroundColor = [UIColor whiteColor];
12     
13     UILabel *testLabel = [[UILabel alloc] initWithFrame:CGRectMake(20, 230, 280, 50)];
14     testLabel.text = @"hello，look at me !";
15     [self.view addSubview:testLabel];
16     
17     JTSlideShadowAnimation *testJT = [[JTSlideShadowAnimation alloc] init];
18     testJT.animatedView = testLabel;
19     testJT.shadowBackgroundColor = [UIColor colorWithWhite:1 alpha:.5];
20     testJT.shadowForegroundColor = [UIColor redColor];
21     testJT.duration = 1.0f;// 时间
22     [testJT start];// 开启动画
23 }
24 
25 
26 @end