ios - 将 UIImage 视图作为子视图添加到 UIView 的实例

Question

我正在练习初学者代码，因为我是新手，在这里我遇到了很多困惑......这就是我到目前为止所拥有的

UIView *catView = [[UIView alloc] init];
UIImage *image = [UIImage imageNamed:@"lolcat.png"];
UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
[catView.view addSubview:imageView];

我不明白这里出了什么问题以及为什么有问题，有人可以帮忙吗？

Answer 1

//You need to specify the frame of the view   
UIView *catView = [[UIView alloc] initWithFrame:CGRectMake(0,0,320,400)];

UIImage *image = [UIImage imageNamed:@"lolcat.png"];
UIImageView *imageView = [[UIImageView alloc] initWithImage:image];

//specify the frame of the imageView in the superview , here it will fill the superview
imageView.frame = catView.bounds;

// add the imageview to the superview
[catView addSubview:imageView];

//add the view to the main view

[self.view addSubview:catView];

Answer 2

有趣而微妙的音符。如果视图已添加到 .xib 文件中，则视图是“弱”的，您需要使用临时变量进行交换。还有一些简单的数学运算可以让坐标与您在视图中设置的坐标相匹配：

@property (weak, nonatomic) IBOutlet UIImageView *imageView1;
@property (weak, nonatomic) IBOutlet UIImageView *imageView2;
CGRect tempFrame; 

tempFrame = self.imageView1.frame;

CGRect tempFrame;   // use bounds instead

tempFrame = self.imageView2.frame;

__strong UIImageView * tempView = self.imageView2;
[self.imageView2 willMoveToSuperview: nil];
[self.imageView2 removeFromSuperview];
[self.imageView2 willMoveToSuperview: self.imageView1];
[self.imageViewSkate addSubview: self.imageViewBall];
self.imageView2.frame = CGRectMake(tempFrame.origin.x - self.imageView1.frame.origin.x,
                                      tempFrame.origin.y - self.imageView1.frame.origin.y,
                                      tempFrame.size.width, tempFrame.size.height);
tempView = nil;