ios - "Unrecognized selector sent to instance"使用自定义表格单元格时

Question

我已经实现了自定义表格单元格，当表格进入 cellForRowAtIndexPath 时收到运行时错误(“无法识别的选择器发送到实例”)。尝试实例化自定义单元格时发生错误。我之前已经成功地做到了这一点，但现在错误不会消失。我有一个 prtotype 单元格，它的自定义类属性设置为自定义单元格 UITableViewCell 子类。这是自定义单元格:

#import "FavoriteCell.h"

@implementation FavoriteCell
@synthesize lblGaugeID, lblMainTitle, bgImage;

- (id)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier
{
    bgImage = [UIImage imageNamed:@"tableCellBG.png"];
    self = [super initWithStyle:style reuseIdentifier:reuseIdentifier];
    if (self) {
        UIColor *transparentBG = [UIColor colorWithRed:0.0 green:0.0 blue:0.0 alpha:0.0];
        UIColor *foregroundColor = [UIColor colorWithRed:1.0 green:1.0 blue:1.0 alpha:1.0];
        //UIColor *shadowColot = [UIColor colorWithWhite:0.75 alpha:1.0];

        CGSize size = self.contentView.frame.size;
        self.backgroundView = [[UIImageView alloc] initWithImage:bgImage];
        self.lblMainTitle = [[UILabel alloc] initWithFrame:CGRectMake(8.0, 0.5, size.width-16, size.height-40)];
        [self.lblMainTitle setFont:[UIFont systemFontOfSize:12.0]];
        [self.lblMainTitle setTextAlignment:NSTextAlignmentLeft];
        [self.lblMainTitle setAutoresizingMask:(UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight)];
        [self.lblMainTitle setBackgroundColor:transparentBG];

        self.lblGaugeID = [[UILabel alloc] initWithFrame:CGRectMake(20.0, 31.0, size.width-16, size.height-40)];
        [self.lblGaugeID setFont:[UIFont boldSystemFontOfSize:15.0]];
        [self.lblGaugeID setTextAlignment:NSTextAlignmentLeft];
        [self.lblGaugeID setTextColor:foregroundColor];
        [self.lblGaugeID setShadowOffset:CGSizeMake(0.2 , 0.2)];
        [self.lblGaugeID setAutoresizingMask:(UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight)];
        [self.lblGaugeID setBackgroundColor:transparentBG];

        [self.contentView addSubview:lblGaugeID];
        [self.contentView addSubview:lblMainTitle];
    }
    return self;
}

@end

这是实例化的地方(摘 self 的 View Controller 类):

-(FavoriteCell*)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    NSString *cellIdentifier = @"favoriteCell";
    FavoriteCell *cell = (FavoriteCell*)[tableView dequeueReusableCellWithIdentifier:cellIdentifier]; //error
    if(cell == nil){
        cell = [[FavoriteCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier];
    }
    NSString *siteName = [faveKeys objectAtIndex:indexPath.row];

    [cell.lblMainTitle setText:siteName];
    [cell.lblGaugeID setText:[allFavorites objectForKey:siteName]];
    return cell;
}

这是完整的错误信息:

* Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFConstantString instantiateWithOwner:options:]: unrecognized selector sent to instance 0x24bb0'

任何人都可以就检查的内容提供一些建议吗？谢谢!薇薇安

Answer 1

使用 - (void)registerNib:(UINib *)nib forCellReuseIdentifier:(NSString *)identifier 是一个如果您在单独的 NIB 文件中定义自定义单元格的好主意 .问题是您传递了 NSString 而不是 UINib 对象。

改为这样做:

[self.tblFavorites registerNib:[UINib nibWithNibName:@"favoriteCellView"bundle:nil] forCellReuseIdentifier:@"favoriteCell"];

但是因为您使用的是原型(prototype)单元而不是单独的 NIB，所以根本没有必要这样做。相反，您只需要确保正确设置原型(prototype)单元格的重用标识符(在本例中为“favoriteCell”)。