利用runtime的关联对象，封装了一个简单易用的Loading控件
统一管理项目中随处可见的Loading控件，提供一组基础的loading控件样式，包括旋转图片的设置和logo的设置，提供便捷的调用方法。
- 提供一个配置类用于配置loading的尺寸、图片等信息
- 封装loading控件，支持loading动画的开启与停止
- 利用runtime的关联对象特性，添加一个
UIView的分类，并管理loadingView，从而达到调用[view beginLoading]和[view endLoading]能方便的在view的中心显示和隐藏loading控件
loading控件配置类，单例模式，持有loadingType、animateImageName、loopImage、logoImage、loadingMessage、loopImageSize、logoImageSize、duration、angleStep、alphaStep等配置信息
#define ZYLoadingConfigInstance [ZYLoadingConfig sharedInstance]
typedef NS_ENUM(NSInteger, ZYLoadingType) {
ZYLoadingAnimateImages, // 传入一组图片组合成动画
ZYLoadingLoopImage // 设置一个图片，旋转图片
};
@interface ZYLoadingConfig : NSObject
+ (instancetype)sharedInstance;
@property (nonatomic, assign) ZYLoadingType loadingType;
@property (nonatomic, strong) NSString *animateImageName;
@property (nonatomic, strong) UIImage *loopImage;
@property (nonatomic, strong) UIImage *logoImage;
@property (nonatomic, strong) NSString *loadingMessage;
@property (nonatomic, assign) CGSize loopImageSize;
@property (nonatomic, assign) CGSize logoImageSize;
@property (nonatomic, assign) CGFloat duration;
@property (nonatomic, assign) CGFloat angleStep;
@property (nonatomic, assign) CGFloat alphaStep;
自定义loading控件，管理loading控件元素的布局，利用[UIView animateWithDuration:delay:options:animations:completion:执行旋转动画
通过CGAffineTransformMakeRotation()旋转loopImageView，动画过程中循环调用达到loading动画的效果。
- (void)loopAnimation {
_loopAngle += _angleStep;
_logoAlpha += _alphaStep;
if (_logoAlpha >= 1.0 || _logoAlpha <= 0.0) {
_alphaStep = - _alphaStep;
}
/*
时间函数曲线
UIViewAnimationOptionCurveEaseInOut 由慢到快 默认
UIViewAnimationOptionCurveEaseIn 由慢到特快
UIViewAnimationOptionCurveEaseOut 由快到慢
UIViewAnimationOptionCurveLinear 匀速 保证旋转动画匀速过渡
*/
[UIView animateWithDuration:ZYLoadingConfigInstance.duration delay:0.0 options:UIViewAnimationOptionCurveLinear animations:^{
CGAffineTransform loopAngleTransform = CGAffineTransformMakeRotation(_loopAngle * (M_PI / 180.f));
_loopImageView.transform = loopAngleTransform;
_logoImageView.alpha = _logoAlpha;
} completion:^(BOOL finished) {
if (_isLoading && [self superview] != nil) {
[self loopAnimation];
} else {
[self removeFromSuperview];
_loopAngle = 0.0;
_logoAlpha = 0.0;
_alphaStep = ABS(_alphaStep);
CGAffineTransform loopAngleTransform = CGAffineTransformMakeRotation(_loopAngle * (M_PI / 180.f));
_loopImageView.transform = loopAngleTransform;
_logoImageView.alpha = _logoAlpha;
}
}];
}
给UIView添加一个分类，利用关联对象的特性给分类添加一个成员变量loadingView，并提供beginLoading和endLoading这两个方法方便的创建loadingView和隐藏loadingView。
- (void)setLoadingView:(ZYLoadingView *)loadingView {
[self willChangeValueForKey:@"LoadingViewKey"];
objc_setAssociatedObject(self, &LoadingViewKey, loadingView, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
[self didChangeValueForKey:@"LoadingViewKey"];
}
- (ZYLoadingView *)loadingView {
return objc_getAssociatedObject(self, &LoadingViewKey);
}
- (void)beginLoading {
if (!self.loadingView) {
self.loadingView = [[ZYLoadingView alloc] initWithFrame:self.bounds];
}
[self addSubview:self.loadingView];
[self.loadingView startAnimation];
}
- (void)endLoading {
if (self.loadingView) {
[self.loadingView stopAnimation];
}
}