WDProjectConfig/UIScrollView+WDNoData.m at master · wuvdan/WDProjectConfig · GitHub

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//
//  UIScrollView+WDNoData.m
//  Test
//
//  Created by wudan on 2018/12/25.
//  Copyright © 2018 wudan. All rights reserved.
//

#import "UIScrollView+WDNoData.h"
#import <objc/runtime.h>

static char *noDataViewKey = "noDataViewKey";

@implementation UIScrollView (WDNoData)

void exchangeSelector(SEL sel1, SEL sel2, Class cls) {
    Class class = [cls class];
    Method originalMethod = class_getInstanceMethod(class, sel1);
    Method swizzledMethod = class_getInstanceMethod(class, sel2);
    BOOL success = class_addMethod(class, sel1, method_getImplementation(swizzledMethod), method_getTypeEncoding(swizzledMethod));
    if (success) {
        class_replaceMethod(class, sel2, method_getImplementation(originalMethod), method_getTypeEncoding(originalMethod));
    } else {
        method_exchangeImplementations(originalMethod, swizzledMethod);
    }
}

#pragma mark =============== Setter ===============
- (void)setNoDataView:(UIView *)noDataView {
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        exchangeSelector(@selector(reloadData), @selector(wd_reloadData), [self class]);
    });

    objc_setAssociatedObject(self, noDataViewKey, noDataView, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}

#pragma mark =============== Getter ===============
- (UIView *)noDataView {
    UIView *noDataView = objc_getAssociatedObject(self, noDataViewKey);
    noDataView.frame = self.frame;
    return noDataView;
}


- (void)wd_reloadData {
    [self wd_reloadData];
    [self wd_checkData];
}

#pragma mark =============== 获取数据 ===============
- (void)wd_checkData {
    NSInteger items = 0;

    if (![self respondsToSelector:@selector(dataSource)]) {
        return;
    }

    // UITableView support
    if ([self isKindOfClass:[UITableView class]]) {

        UITableView *tableView = (UITableView *)self;
        id <UITableViewDataSource> dataSource = tableView.dataSource;

        NSInteger sections = 1;

        if (dataSource && [dataSource respondsToSelector:@selector(numberOfSectionsInTableView:)]) {
            sections = [dataSource numberOfSectionsInTableView:tableView];
        }

        if (dataSource && [dataSource respondsToSelector:@selector(tableView:numberOfRowsInSection:)]) {
            for (NSInteger section = 0; section < sections; section++) {
                items += [dataSource tableView:tableView numberOfRowsInSection:section];
            }
        }
    }
    // UICollectionView support
    else if ([self isKindOfClass:[UICollectionView class]]) {

        UICollectionView *collectionView = (UICollectionView *)self;
        id <UICollectionViewDataSource> dataSource = collectionView.dataSource;

        NSInteger sections = 1;

        if (dataSource && [dataSource respondsToSelector:@selector(numberOfSectionsInCollectionView:)]) {
            sections = [dataSource numberOfSectionsInCollectionView:collectionView];
        }

        if (dataSource && [dataSource respondsToSelector:@selector(collectionView:numberOfItemsInSection:)]) {
            for (NSInteger section = 0; section < sections; section++) {
                items += [dataSource collectionView:collectionView numberOfItemsInSection:section];
            }
        }
    }

    if ( items == 0 ) {
        [self addSubview:self.noDataView];
    } else {
        [self.noDataView removeFromSuperview];
    }
}

@end