iOS中利用CoreAnimation实现一个时间的进度条效果

2019-10-21 18:44:57

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在iOS中实现进度条通常都是通过不停的设置progress来完成的，这样的进度条适用于网络加载（上传下载文件、图片等）。但是对于录制视频这样的需求的话，如果是按照每秒来设置进度的话，显得有点麻烦，于是我就想直接用CoreAnimation来按时间做动画，只要设置最大时间，其他的就不用管了，然后在视频暂停与继续录制时，对动画进行暂停和恢复即可。录制视频的效果如下：

coreanimation,时间,进度条

你可以在这里下载demo

那么接下来就是如何用CoreAnimation实现一个进度条控件了。

首先呢，让我们创建一个继承自CAShapeLayer的WKProgressBarLayer。

WKProgressBarLayer默认自身的bounds就是整个进度条的大小。

@interface WKProgressBarLayer : CAShapeLayer@end

为了方便外部调用，首先在WKProgressBarLayer.h中定义枚举来表明动画的四个状态

typedef NS_ENUM(NSInteger, WKAnimationStatus) { WKAnimationStatusIdle,//空闲 WKAnimationStatusAnimating,//动画中 WKAnimationStatusPause,//暂停 WKAnimationStatusComplete//完成};

接下来，定义外部调用的动画接口

@interface WKProgressBarLayer : CAShapeLayer@property (nonatomic, assign, readonly) WKAnimationStatus animatingStatus;//状态/** 开始动画 @param duration 动画最大时长 */- (void)beginAnimationWithDuration:(CGFloat)duration;/** 暂停 */- (void)pauseAnimation;/** 恢复 */- (void)resumeAnimation;/** 重新开始动画 @param progress 从哪个进度开始 @param duration 动画最大时长 */- (void)restartAnimationWithProgress:(CGFloat)progress duration:(NSTimeInterval)duration;@end

然后，我们在.m实现核心的动画开始方法startAnimtionWithBeginProgress:duration:，详细解释见代码

- (void)startAnimtionWithBeginProgress:(CGFloat)beginProgress duration:(NSTimeInterval)duration{ [self reset];//重置动画 //设置path UIBezierPath *fromPath = [UIBezierPath bezierPathWithRect:CGRectMake(0, 0, beginProgress * self.bounds.size.width, self.bounds.size.height)];; UIBezierPath *toPath = [UIBezierPath bezierPathWithRect:self.bounds]; self.path = fromPath.CGPath; //创建动画 CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"path"]; animation.fromValue = (id)fromPath.CGPath; animation.toValue = (id)toPath.CGPath; animation.duration = duration; [animation setValue:@1 forKey:@"progress"];//用于判断是否是进度动画 animation.delegate = self; //用于判断动画结束 [self addAnimation:animation forKey:@"progressAnimation"]; self.path = toPath.CGPath;}

然后呢，需要在动画的delegate与暂停、恢复动画的方法中分别修改动画的状态

- (void)pauseAnimation{ CFTimeInterval pausedTime = [self convertTime:CACurrentMediaTime() fromLayer:nil]; self.speed = 0.0; self.timeOffset = pausedTime; self.animatingStatus = WKAnimationStatusPause;}- (void)resumeAnimation{ CFTimeInterval pausedTime = [self timeOffset]; self.speed = 1.0; self.timeOffset = 0.0; self.beginTime = 0.0; CFTimeInterval timeSincePause = [self convertTime:CACurrentMediaTime() fromLayer:nil] - pausedTime; self.beginTime = timeSincePause; self.animatingStatus = WKAnimationStatusAnimating;}#pragma mark - CAAnimationDelegate/* Called when the animation begins its active duration. */- (void)animationDidStart:(CAAnimation *)anim{ if (anim == [self animationForKey:@"progressAnimation"]) {//判断进度动画  self.animatingStatus = WKAnimationStatusAnimating; }}- (void)animationDidStop:(CAAnimation *)anim finished:(BOOL)flag{ if ([anim valueForKey:@"progress"] && flag == YES) {//判断进度动画  self.animatingStatus = WKAnimationStatusComplete; }}

至此，进度条layer就完成了，现在创建一个控制器来做测试

首先在storyBoard摆上两个按钮，分别是开始与重置动画(界面搭建很简单，详情见demo)

然后在ViewDidLoad中添加progressLayer

- (void)viewDidLoad { [super viewDidLoad];   WKProgressBarLayer *progressLayer = [[WKProgressBarLayer alloc] init]; progressLayer.frame = CGRectMake(100, 100, 200, 10);   [self.view.layer addSublayer:progressLayer];   self.progressLayer = progressLayer;}

接下来，就是动画开始与重置响应

- (IBAction)startOrPauseAction:(UIButton *)sender {  switch (self.progressLayer.animatingStatus) {   case WKAnimationStatusIdle:{    [self.progressLayer beginAnimationWithDuration:10];   }    break;   case WKAnimationStatusAnimating:{    [self.progressLayer pauseAnimation];   }    break;   case WKAnimationStatusPause:{    [self.progressLayer resumeAnimation];   }    break;   case WKAnimationStatusComplete:{    [self.progressLayer restartAnimationWithProgress:0 duration:10];   }    break;   default:    break; } sender.selected = !sender.selected;}- (IBAction)resetAction:(UIButton *)sender { [self.progressLayer restartAnimationWithProgress:0 duration:10]; self.startOrPauseButton.selected = YES;}

以上就是代码主体了，接下来，让我们看看效果

coreanimation,时间,进度条