IOS等待时动画效果的实现

查询时间或长或短，为了提升用户体验，目前用的比较多的手段之一就是查询等待时添加一个动态等待效果。当我们在请求网络时加载页面时有个动作效果，效果图如下：

源代码可以网上找开源项目Coding.net，上面的效果原理为两张图片组合，外面那个则为动画转动，里面的图标则是透明度的变化；主要代码如下：

1：把它封装在EaseLoadingView里面

@interface EaseLoadingView : UIView
@property (strong, nonatomic) UIImageView *loopView, *monkeyView;
@property (assign, nonatomic, readonly) BOOL isLoading;
- (void)startAnimating;
- (void)stopAnimating;
@end
@interface EaseLoadingView ()
@property (nonatomic, assign) CGFloat loopAngle, monkeyAlpha, angleStep, alphaStep;
@end

@implementation EaseLoadingView
- (instancetype)initWithFrame:(CGRect)frame{
 self = [super initWithFrame:frame];
 if (self) {
  self.backgroundColor = [UIColor clearColor];
  _loopView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"loading_loop"]];
  _monkeyView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"loading_monkey"]];
  [_loopView setCenter:self.center];
  [_monkeyView setCenter:self.center];
  [self addSubview:_loopView];
  [self addSubview:_monkeyView];
  [_loopView mas_makeConstraints:^(MASConstraintMaker *make) {
   make.center.equalTo(self);
  }];
  [_monkeyView mas_makeConstraints:^(MASConstraintMaker *make) {
   make.center.equalTo(self);
  }];
  _loopAngle = 0.0;
  _monkeyAlpha = 1.0;
  _angleStep = 360/3;
  _alphaStep = 1.0/3.0;
 }
 return self;
}
- (void)startAnimating{
 self.hidden = NO;
 if (_isLoading) {
  return;
 }
 _isLoading = YES;
 [self loadingAnimation];
}
- (void)stopAnimating{
 self.hidden = YES;
 _isLoading = NO;
}
- (void)loadingAnimation{
 static CGFloat duration = 0.25f;
 _loopAngle += _angleStep;
 if (_monkeyAlpha >= 1.0 || _monkeyAlpha <= 0.0) {
  _alphaStep = -_alphaStep;
 }
 _monkeyAlpha += _alphaStep;
 [UIView animateWithDuration:duration delay:0.0 options:UIViewAnimationOptionCurveLinear animations:^{
  CGAffineTransform loopAngleTransform = CGAffineTransformMakeRotation(_loopAngle * (M_PI / 180.0f));
  _loopView.transform = loopAngleTransform;
  _monkeyView.alpha = _monkeyAlpha;
 } completion:^(BOOL finished) {
  if (_isLoading && [self superview] != nil) {
   [self loadingAnimation];
  }else{
   [self removeFromSuperview];
   _loopAngle = 0.0;
   _monkeyAlpha = 1,0;
   _alphaStep = ABS(_alphaStep);
   CGAffineTransform loopAngleTransform = CGAffineTransformMakeRotation(_loopAngle * (M_PI / 180.0f));
   _loopView.transform = loopAngleTransform;
   _monkeyView.alpha = _monkeyAlpha;
  }
 }];
}
@end

注意loadingAnimation这里面有动作的处理及透明度的处理，当停止加载后把它自个从当前的视图去除；

2：UIView (Common)在UIView扩展类里

#pragma mark LoadingView
@property (strong, nonatomic) EaseLoadingView *loadingView;
- (void)beginLoading;
- (void)endLoading;
@end
- (void)setLoadingView:(EaseLoadingView *)loadingView{
 [self willChangeValueForKey:@"LoadingViewKey"];
 objc_setAssociatedObject(self, &LoadingViewKey,
        loadingView,
        OBJC_ASSOCIATION_RETAIN_NONATOMIC);
 [self didChangeValueForKey:@"LoadingViewKey"];
}
- (EaseLoadingView *)loadingView{
 return objc_getAssociatedObject(self, &LoadingViewKey);
}
- (void)beginLoading{
 for (UIView *aView in [self.blankPageContainer subviews]) {
  if ([aView isKindOfClass:[EaseBlankPageView class]] && !aView.hidden) {
   return;
  }
 }
 if (!self.loadingView) { //初始化LoadingView
  self.loadingView = [[EaseLoadingView alloc] initWithFrame:self.bounds];
 }
 [self addSubview:self.loadingView];
 [self.loadingView mas_makeConstraints:^(MASConstraintMaker *make) {
  make.self.edges.equalTo(self);
 }];
 [self.loadingView startAnimating];
}
- (void)endLoading{
 if (self.loadingView) {
  [self.loadingView stopAnimating];
 }
}

注意：cocoa的KVO模型中，有两种通知观察者的方式，自动通知和手动通知。顾名思义，自动通知由cocoa在属性值变化时自动通知观察者，而手动通知需要在值变化时调用 willChangeValueForKey:和didChangeValueForKey: 方法通知调用者。

3：使用页面调用

- (void)sendRequest{
 [self.view beginLoading];
 __weak typeof(self) weakSelf = self;
 [[Coding_NetAPIManager sharedManager] request_CodeFile:_myCodeFile withPro:_myProject andBlock:^(id data, NSError *error) {
  [weakSelf.view endLoading];
  if (data) {
   weakSelf.myCodeFile = data;
   [weakSelf refreshCodeViewData];
  }
  [weakSelf.view configBlankPage:EaseBlankPageTypeView hasData:(data != nil) hasError:(error != nil) reloadButtonBlock:^(id sender) {
   [weakSelf sendRequest];
  }];
 }];
}

其中[self.view beginLoading]跟[weakSelf.view endLoading]就可以调用动画效果；

补充：另一种是有很多不同的图片组成的动画效果，可以用每一张图片然后FOR遍历组成出动作效果；

//设置普通状态的动画图片
 NSMutableArray *idleImages = [NSMutableArray array];
 for (NSUInteger i = 1; i<=60; ++i) {
    UIImage *image = [UIImage imageNamed:[NSString stringWithFormat:@"dropdown_anim__000%zd",i]];
    [idleImages addObject:image];
  [idleImages addObject:image];
 }

以上内容是本文通过IOS等待时动画效果的实现，希望对大家有所帮助。