iOS开发MJRefresh结合Lottie使用

现在很多的app下拉刷新有好多好看动画效果，我们可以使用MJRefresh和Lottie来实现这个效果。
1、添加第三方库：

pod 'MJRefresh'
pod 'lottie-ios', '=2.5.3'

2、创建MJRefreshGifHeader的子类RefreshGifHeaderLottie
RefreshGifHeaderLottie.h

#import <Foundation/Foundation.h>
#import "MJRefreshGifHeader.h"
NS_ASSUME_NONNULL_BEGIN

@interface RefreshGifHeaderLottie : MJRefreshGifHeader
- (void)setJsonName:(NSString *)jsonName;
@end

NS_ASSUME_NONNULL_END

RefreshGifHaderLottie.m

#import "RefreshGifHeaderLottie.h"
#import <AudioToolbox/AudioToolbox.h>
#import <Lottie/Lottie.h>
@interface RefreshGifHeaderLottie ()
@property(nonatomic, strong) LOTAnimationView *loadingView;
@property(nonatomic, strong) NSString *jsonString;
@end
@implementation RefreshGifHeaderLottie

- (instancetype)init
{
    if (self = [super init])
    {
        self.lastUpdatedTimeLabel.hidden = YES;
        self.stateLabel.hidden = YES;
    }
    return self;
}

- (LOTAnimationView *)loadingView
{
    if (!_loadingView)
    {
        _loadingView = [LOTAnimationView animationNamed:self.jsonString];
        _loadingView.frame = CGRectMake(kScreenWidth/2 - 25, 0, 50, 50);
        _loadingView.loopAnimation = YES;
        _loadingView.contentMode = UIViewContentModeScaleAspectFill;
        _loadingView.animationSpeed = 1.0;
    }
    return _loadingView;
}

- (void)setJsonName:(NSString *)jsonName
{
    self.jsonString = jsonName;
    [self addSubview:self.loadingView];
}

#pragma mark - innerMethod
- (void)beginRefreshing
{
    if (@available(iOS 10.0, *))
    {
        UIImpactFeedbackGenerator *impactLight = [[UIImpactFeedbackGenerator alloc] initWithStyle:UIImpactFeedbackStyleMedium];
        [impactLight impactOccurred];
    }
    else
    {
        AudioServicesPlaySystemSound(1502);
    }
    [super beginRefreshing];
}

#pragma mark - 监听控件的刷新状态
- (void)setState:(MJRefreshState)state
{
    MJRefreshCheckState;
    if (self.jsonString.length > 0)
    {
        switch (state)
        {
            case MJRefreshStateIdle: /// 普通闲置状态
            {
                [self.loadingView stop];
                break;
            }
            case MJRefreshStatePulling:
            {
                break;
            }
            case MJRefreshStateRefreshing:
            {
                self.loadingView.animationProgress = 0;
                [self.loadingView play];
                break;
            }
            default:
                break;
        }
    }
}

#pragma mark - 实时监听控件 scrollViewContentOffset
- (void)scrollViewContentOffsetDidChange:(NSDictionary *)change
{
    [super scrollViewContentOffsetDidChange:change];
    if (self.jsonString.length > 0)
    {
        CGPoint point;
        id newVelue = [change valueForKey:NSKeyValueChangeNewKey];
        [(NSValue *)newVelue getValue:&point];
        
        self.loadingView.hidden = !(self.pullingPercent);
        CGFloat progress = point.y / (kScreenHeight/3.0);
        if (self.state != MJRefreshStateRefreshing)
        {
            self.loadingView.animationProgress = -progress;
        }
    }
}
@end

3、控制器中的使用
懒加载RefreshGifHeaderLottie

- (RefreshGifHeaderLottie *)refreshGifHeaderLottie
{
    if (!_refreshGifHeaderLottie)
    {
        _refreshGifHeaderLottie = [RefreshGifHeaderLottie new];
    }
    return _refreshGifHeaderLottie;
}

tableView中使用

[self.refreshGifHeaderLottie setJsonName:@"headerRefresh.json"];
self.homeView.tableView.mj_header = self.refreshGifHeaderLottie;
[self.refreshGifHeaderLottie setRefreshingBlock:^{
        
}];