ios - 在 awakeFromNib 中获取导出尺寸

Question

我创建了一个自定义 UICollectionViewCell，其中包含一个标 checkout 口(放置在 Storyboard 中)。我想从自定义 UICollectionViewCell 的 awakeFromNib 方法中获取此标签的高度，但标签的大小始终为 0.000000:

// .h
@interface MyCustomCell : UICollectionViewCell

@property (weak, nonatomic) IBOutlet UILabel *myLabel;

@end

// .m
@implementation MyCustomCell

-(void)awakeFromNib
{
    [super awakeFromNib];

    NSLog(@"%@", self.myLabel);
    NSLog(@"%f", self.myLabel.frame.size.width);
    NSLog(@"%f", self.myLabel.frame.size.height);
}

@end

控制台输出:

2013-02-06 11:13:59.628 Test[8880:c07] <UILabel: 0x7649a00; frame = (0 0; 0 0); text = '12h00'; clipsToBounds = YES; opaque = NO; autoresize = TM+BM; userInteractionEnabled = NO; layer = <CALayer: 0x7649ac0>>
2013-02-06 11:13:59.628 Test[8880:c07] 0.000000
2013-02-06 11:13:59.630 Test[8880:c07] 0.000000

如何获得标签的尺寸？调用 awakeFromNib 时获取此类信息是否为时过早？如果是这样，我应该通过自定义单元格的哪种方法获得尺寸？

编辑

这是在 ViewController 中观察到的同样奇怪的行为:

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
    MyCustomCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"MyCustomCell" forIndexPath:indexPath];
    NSLog(@"%@", cell);
    NSLog(@"%@", cell.myLabel);
}

输出:

2013-02-07 16:07:34.488 Test[30308:c07] <MyCustomCell: 0x7156980; baseClass = UICollectionViewCell; frame = (20 0; 290 655); clipsToBounds = YES; opaque = NO; layer = <CALayer: 0x7156a80>>
2013-02-07 16:07:34.489 Test[30308:c07] <UILabel: 0x7158100; frame = (0 0; 0 0); text = 'this is a text'; clipsToBounds = YES; opaque = NO; autoresize = TM+BM; userInteractionEnabled = NO; layer = <CALayer: 0x7158040>>

Answer 1

部分答案在 dreamzor 对 iOS AutoLayout - get frame size width 的回复中.

The trick is to place your frame-dependent code to the viewDidLayoutSubviews method

在我的特殊情况下，我发现在我的自定义单元格 awakeFromNib 方法中添加 [self layoutIfNeeded];，就在询问导出尺寸之前，效果非常好。