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:
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
你可以在这里下载demo
总结
以上所述是小编给大家介绍的iOS中利用CoreAnimation实现一个时间的进度条,希望对大家有所帮助,如果大家有任何疑问请给我留言,小编会及时回复大家的。在此也非常感谢大家对脚本之家网站的支持!