方法交换

交换tableview reloadData 方法实现空数据提示

static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        Method oldMethod = class_getInstanceMethod(self, @selector(reloadData));
        Method newMethod = class_getInstanceMethod(self, @selector(lz_reloadData));
        method_exchangeImplementations(oldMethod, newMethod);
    });
- (void)lj_reloadData {
    [self lj_reloadData];
    [self filColor];
}
- (void)filColor {
    id<UITableViewDataSource> dataSource = self.dataSource;
    NSInteger section = [dataSource respondsToSelector:@selector(numberOfSectionsInTableView:)] ? [dataSource respondsToSelector:@selector(numberOfSectionsInTableView:)] : 1;
    NSInteger row = 0;
    for (NSInteger i = 0; i < section; i++) {
        row += [dataSource tableView:self numberOfRowsInSection:i];
    }
    if (row > 0) {
        self.backgroundColor = [UIColor redColor];
    }else {
        self.backgroundColor = [UIColor whiteColor];
    }
}