ios - 复合 View 的 addSubview 不起作用

Question

我有一个 UIView它由两个 subview 组成-

@interface ANImageLabel : UIView

@property (strong, nonatomic) UIImageView *imageView;
@property (strong, nonatomic) UILabel *label;

- (id)initWithFrameAtOrigin:(CGPoint)origin imageViewSize:(CGSize)imageViewSize labelSize:(CGSize)labelSize;

@end

- (id)initWithFrameAtOrigin:(CGPoint)origin imageViewSize:(CGSize)imageViewSize labelSize:(CGSize)labelSize
{
    CGRect frame = CGRectZero;
    frame.origin = origin;

    // height should be the max of both heights
    CGFloat height = MAX(imageViewSize.height, labelSize.height);
    CGFloat width = imageViewSize.width + labelSize.width;
    imageViewSize.height = labelSize.height = frame.size.height = height;
    frame.size.width = width;

    self = [super initWithFrame:frame];
    if (self) {
        // Initialization code
        CGRect imageViewFrame = CGRectZero;
        imageViewFrame.origin = origin;
        imageViewFrame.size = imageViewSize;
        self.imageView = [[UIImageView alloc] initWithFrame:imageViewFrame];
        self.imageView.contentMode = UIViewContentModeCenter;
        [self addSubview:self.imageView];

        CGRect labelFrame = CGRectZero;
        labelFrame.origin.x = origin.x + imageViewSize.width;
        labelFrame.origin.y = origin.y;
        labelFrame.size = labelSize;
        self.label = [[UILabel alloc] initWithFrame:labelFrame];
        [self addSubview:self.label];
    }
    return self;
}

我 alloc-init这个 View 的一个实例( anImageLabelInstance )在另一个 View ( mySuperView )中，我想将它添加为 subview 。
但是，如果我直接将此 View 添加为 subview ，则它不起作用。

[mySuperView addSubview:anImageLabelInstance]; <--- DOESN'T WORK, WHY?

另一方面，如果我单独添加 View ，它可以工作-

    [anImageLabelInstance.subviews enumerateObjectsUsingBlock:^(UIView *view, NSUInteger idx, BOOL *stop) {
        [mySuperView addSubview:view];
    }];

addSubview的描述说

If view already has a superview and that view is not the receiver, this method removes the previous superview before making the receiver its new superview.

但是，由于 anImageLabelInstance在此操作之前最初没有作为 subview 添加到任何其他 View ，为什么我需要单独添加 View ？ View 的所有 subview 不都应该添加 addSubview吗？方法？

Answer 1

看起来您没有正确设置 2 个 subview 的框架。
您将原点传递给 init 方法，可以设置 ANImageView 框架，但不能设置 subview 。

因此，假设您通过了一个原点 (200, 200):ANImageLabel View 将放入您我的 super View 在 (200, 200)。

如果您随后将 2 个 subview 设置为相同的原点，它们将被放置在相对于 ANImageLabel 框架的坐标 (200, 200) 上，因此它们可能会落在实际 View 框架之外。更准确地说

|''''''''''''''| -> your mySuperView
|              |
|              |
|              |
|              |
|    |''''|--- |----> you ANImageView on (200, 200)
|    |    |    |
|    ''''''    |
|              |
|           ---|-------> somewhere around here (but inside the ANImageView) you have your 2 
|              |         subviews, centered in relation to the ANImageViewFrame (so (400, 400)  
''''''''''''''''         in relation to the mySuperView)

在这种情况下，这 2 个 subview 将在 ANImageView 的可见区域之外，因此被隐藏。当然如果你再单独捡起来直接放到 我的 super View ，它们的原点 (200, 200) 实际上将相对于 我的 super View 框架，并且可能在其可见区域中，因此没有隐藏。

试着把这个:

        CGRect imageViewFrame = CGRectZero;
        imageViewFrame.origin = origin;
        imageViewFrame.size = imageViewSize;
        self.imageView = [[UIImageView alloc] initWithFrame:imageViewFrame];
        self.imageView.contentMode = UIViewContentModeCenter;
        [self addSubview:self.imageView];

        CGRect labelFrame = CGRectZero;
        labelFrame.origin.x = origin.x + imageViewSize.width;
        labelFrame.origin.y = origin.y;
        labelFrame.size = labelSize;
        self.label = [[UILabel alloc] initWithFrame:labelFrame];
        [self addSubview:self.label];

进入这个:

    CGRect imageViewFrame = CGRectZero;
    imageViewFrame.origin = CGPointMake(0,0);
    imageViewFrame.size = imageViewSize;
    self.imageView = [[UIImageView alloc] initWithFrame:imageViewFrame];
    self.imageView.contentMode = UIViewContentModeCenter;
    [self addSubview:self.imageView];

    CGRect labelFrame = CGRectZero;
    labelFrame.origin.x = imageViewSize.width;
    labelFrame.origin.y = 0;
    labelFrame.size = labelSize;
    self.label = [[UILabel alloc] initWithFrame:labelFrame];
    [self addSubview:self.label];

看看它是否得到修复。