OC：封装 MJRefresh

背景： 为了避免写大量重复代码，故封装了该分类。本次只是封装了 MJRefresh 的常用场景，包括 Header 封装了 MJRefreshNormalHeader 的样式，Footer 封装了 MJRefreshBackNormalFooter 和 MJRefreshAutoNormalFooter 的样式。如果不能满足需求，可以在此基础上修改。

封装的代码

UIScrollView+MZRefresh.h

#import <UIKit/UIKit.h>

@interface UIScrollView (MZRefresh)

/** 当前页码 */
@property (nonatomic, assign) NSInteger currentPage;
/** 每页的数据，默认为20条 */
@property (nonatomic, assign) NSInteger pageSize;
/** 是否展示`最后更新时间`，默认为`YES`；如果设为`NO`，则stateLabel就居中显示 */
@property (nonatomic, assign) BOOL showLastUpdatedTimeLabel;

- (void)addHeaderWithDataBlock:(void(^)(void))block;
- (void)addAutoFooter:(BOOL)isTrue withDataBlock:(void(^)(void))block;

/** 提示没有更多数据 */
- (void)endFooterWithNoMoreData;
/** 停止header和footer刷新 */
- (void)endRefreshing;

@end

UIScrollView+MZRefresh.m

#import "UIScrollView+MZRefresh.h"

#import <objc/runtime.h>
#import <MJRefresh/MJRefresh.h>

@implementation UIScrollView (MZRefresh)

- (void)addHeaderWithDataBlock:(void(^)(void))block {
    
    __weak typeof(self) weakself = self;
    MJRefreshNormalHeader *header = [MJRefreshNormalHeader headerWithRefreshingBlock:^{
        
        weakself.currentPage = 0;
        weakself.pageSize = weakself.pageSize;
        [weakself.mj_footer resetNoMoreData];
        
        block();
    }];
    
    if (!self.showLastUpdatedTimeLabel) {
        header.lastUpdatedTimeLabel.hidden = YES;
        header.stateLabel.textAlignment = NSTextAlignmentCenter;
    }
    
    self.mj_header = header;
}

- (void)addAutoFooter:(BOOL)isTrue withDataBlock:(void(^)(void))block {
    
    MJRefreshFooter *footer;
    __weak typeof(self) weakself = self;
    
    if (isTrue) {
        footer = [MJRefreshAutoNormalFooter footerWithRefreshingBlock:^{
            weakself.currentPage++;
            block();
        }];
    } else {
        footer = [MJRefreshBackNormalFooter footerWithRefreshingBlock:^{
            weakself.currentPage++;
            block();
        }];
    }
    self.mj_footer = footer;
}

- (void)endRefreshing {
    [self.mj_header endRefreshing];
    [self.mj_footer endRefreshing];
}

- (void)endFooterWithNoMoreData {
    [self.mj_footer endRefreshingWithNoMoreData];
}


#pragma mark - Getters / Setters

- (NSInteger)currentPage {
    return [objc_getAssociatedObject(self, _cmd) integerValue];
}

- (void)setCurrentPage:(NSInteger)currentPage {
    objc_setAssociatedObject(self, @selector(currentPage), @(currentPage), OBJC_ASSOCIATION_RETAIN);
}

- (NSInteger)pageSize {
    NSNumber *count = objc_getAssociatedObject(self, _cmd);
    if (count) {
        return count.integerValue;
    }
    self.pageSize = 20;
    return 20;
}

- (void)setPageSize:(NSInteger)pageSize {
    objc_setAssociatedObject(self, @selector(pageSize), @(pageSize), OBJC_ASSOCIATION_RETAIN);
}

- (BOOL)showLastUpdatedTimeLabel {
    NSNumber *show = objc_getAssociatedObject(self, _cmd);
    if (show) {
        return show.boolValue;
    }
    self.showLastUpdatedTimeLabel = YES;
    return YES;
}

- (void)setShowLastUpdatedTimeLabel:(BOOL)showLastUpdatedTimeLabel {
    objc_setAssociatedObject(self, @selector(showLastUpdatedTimeLabel), @(showLastUpdatedTimeLabel), OBJC_ASSOCIATION_RETAIN);
}

@end

使用示例：

#import "ViewController.h"

#import "UIScrollView+MZRefresh.h"
#import <MJRefresh/MJRefresh.h>

@interface ViewController ()<UITableViewDelegate, UITableViewDataSource>

@property (weak, nonatomic) IBOutlet UITableView *mTableView;
@property (nonatomic, strong) NSMutableArray *dataList;
@property (nonatomic, assign) NSInteger pageSize;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    [self.mTableView registerClass:[UITableViewCell class] forCellReuseIdentifier:NSStringFromClass([UITableViewCell class])];
    
    self.mTableView.pageSize = self.pageSize = 10;
    [self addDatas];
    [self addRefresh];
}

// 添加 MJRefresh
- (void)addRefresh {
    __weak typeof(self) weakself = self;
    
    // 不展示最近刷新时间
    self.mTableView.showLastUpdatedTimeLabel = NO;
    
    // 添加 Header
    [self.mTableView addHeaderWithDataBlock:^{
        [weakself pullToRefresh];
    }];
    
    // 添加 Footer
    [self.mTableView addAutoFooter:YES withDataBlock:^{
        [weakself addDatas];
    }];
}

// 模拟网络请求
- (void)addDatas {
    
    NSUInteger count = self.dataList.count;
    
    if (count >= 3 * self.pageSize - 1) {
        // 模拟加载完全部数据
        [self.mTableView endFooterWithNoMoreData];
        return;
    }
    
    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(1.5 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
        for (NSInteger i = 0; i < self.pageSize; i++) {
            [self.dataList addObject:[NSString stringWithFormat:@"%ld", count + i]];
        }
        // 停止刷新
        [self.mTableView endRefreshing];
        [self.mTableView reloadData];
    });
}

- (void)pullToRefresh {
    [self.dataList removeAllObjects];
    [self addDatas];
}


#pragma mark - tableViewDataSource && tableViewDelegate

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    return self.dataList.count;
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:NSStringFromClass([UITableViewCell class])];
    cell.selectionStyle = UITableViewCellSelectionStyleNone;
    cell.textLabel.text = self.dataList[indexPath.row];
    return cell;
}

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    
}

- (void)dealloc {
    NSLog(@"ViewController 释放了");
}

- (NSMutableArray *)dataList {
    if (!_dataList) {
        _dataList = [NSMutableArray array];
    }
    return _dataList;
}

@end