ios - 自定义 Collection View 单元格的重写方法不调用

Question

我有一个自定义 Collection View 单元格:BaseCollectionViewCell，我扩展了该类并产生了PastMonth CurrentMonth FutureMonth子类。但是，当我运行该应用程序时，他们假定的覆盖方法 -setView- 不起作用。

这是委托(delegate)方法:

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{
    if (indexPath.row == self.currentIndex && self.currentIndex != 0) {
    AnotherExampleCollectionViewCell* cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"AnotherExampleCollectionViewCell" forIndexPath:indexPath];
    return cell;
    }
    int typeOfMonth = [self findTypeOfMonth:(int)indexPath.row birthDate:self.birthDate];
    switch (typeOfMonth) {
        case 0: {
        PastMonth* cell = (PastMonth*)[collectionView dequeueReusableCellWithReuseIdentifier:@"BaseCollectionViewCell" forIndexPath:indexPath];
        [cell setView];
        return cell;
    }
        case 1:{
        CurrentMonth* cell = (CurrentMonth*)[collectionView dequeueReusableCellWithReuseIdentifier:@"BaseCollectionViewCell" forIndexPath:indexPath];
        [cell setView];
        return cell;
    }
        default:{
        FutureMonth* cell = (FutureMonth*)[collectionView dequeueReusableCellWithReuseIdentifier:@"BaseCollectionViewCell" forIndexPath:indexPath];
        [cell setView];
        return cell;
    }
}

这是 BaseCollectionViewCell.h 和 .m:

#import <UIKit/UIKit.h>
@interface BaseCollectionViewCell : UICollectionViewCell

@property (strong, nonatomic) IBOutlet UIView *coverView;

-(void) setView;
@end



#import "BaseCollectionViewCell.h"

@implementation BaseCollectionViewCell

- (void)awakeFromNib {
// Initialization code
}

-(void) setView{
   NSLog(@"asdasd");
}
@end

这是 CurrentMonth.m:(我没有放其他文件，因为它们几乎相同):

#import "BaseCollectionViewCell.h"
@interface CurrentMonth : BaseCollectionViewCell
-(void) setView;
@end

#import "CurrentMonth.h"

@implementation CurrentMonth

/*
// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during            animation.
- (void)drawRect:(CGRect)rect {
// Drawing code
}
*/
-(void) setView{
    self.coverView.hidden = YES;
    [self.contentView setBackgroundColor:[UIColor yellowColor]];
}
@end

例如，为什么不调用 CurrentMonth 的 setView 而调用 BaseCollectionViewCell 的 setView 方法？

谢谢 :)

Answer 1

您必须使用 registerClass 为每个单元格标识符注册正确的类

[self.collectionView registerClass:[CurrentMonth class] forCellWithReuseIdentifier:@"CurrentMonthCollectionViewCell"];

与其他类(class)类似，您需要这样做。

来自 Apple 文档:

You typically do not create instances of this class yourself. Instead, you register your specific cell subclass (or a nib file containing a configured instance of your class) with the collection view object. When you want a new instance of your cell class, call the dequeueReusableCellWithReuseIdentifier:forIndexPath: method of the collection view object to retrieve one.

你确定你正在这样做吗？

或者，如果您的单元格位于 xib 中，则必须为 xib 中的单元格设置适当的自定义类