使用 Objective-C 以编程方式创建 UIView，以纵向和横向工作-解网

问：

我必须在目标 c 中创建一个包含两个标签的视图，label1 具有单行，label2 是基于内容的多行。

根据标签中的内容，我想调整视图高度，我该怎么做？

视图的宽度应该是 20 左右到屏幕宽度，使用以下代码我可以纵向显示，但在横向中它没有正确出现，它在右侧裁剪。我怎样才能为风景显示正确的 20？

肖像

景观

    UIView *emptyTreeView = [[UIView alloc] initWithFrame:CGRectMake(20,20,self.view.frame.size.width - 40,400)];
    UILabel *label1 =  [[UILabel alloc] initWithFrame:CGRectMake(30.0, 30.0, self.view.frame.size.width - 100, 30.0)];
    UILabel *label2 = [[UILabel alloc] initWithFrame:CGRectMake(30.0, 90.0, self.view.frame.size.width - 100, 100.0)];
    emptyTreeView.backgroundColor=[UIColor blueColor];
    label1.backgroundColor = [UIColor redColor];
    label1.textAlignment = NSTextAlignmentCenter;
    label1.textColor = [UIColor blackColor];
    label1.font = [UIFont boldSystemFontOfSize:18];
    label1.numberOfLines = 0;
    label1.text = @"The Page Cannot be displayed.";
    label2.backgroundColor = [UIColor whiteColor];
    label2.textAlignment = NSTextAlignmentCenter;
    label2.textColor = [UIColor grayColor];
    label2.font = [UIFont systemFontOfSize:15];
    label2.numberOfLines = 0;
    label2.text = @"Please use this feature or contact your internal contact person directly.";
    [emptyTreeView addSubview:label1];
    [emptyTreeView addSubview:label2];
    [self.view addSubview:emptyTreeView];

我做错了什么吗？

IOS Objective-C UIView

不要在中添加子视图。这仅用于调整值。viewDidLayoutSubviewsframe
如果引用，请引用其，而不是其。前者用于内的子视图的坐标。后者位于其上视图的坐标系中（目前可能不会引入任何差异，但只是错误的坐标系。self.viewboundsframeself.view

如果您希望视图在旋转时调整大小，请将其设置为，例如autoresizingMask

emptyTreeView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleBottomMargin;

或

emptyTreeView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleBottomMargin;

如今，设置帧值和自动调整蒙版大小有点不合时宜。我们通常会使用约束，例如

- (void)viewDidLoad {
    [super viewDidLoad];

    UIView *emptyTreeView = [[UIView alloc] init];
    UILabel *label1 =  [[UILabel alloc] init];
    UILabel *label2 = [[UILabel alloc] init];
    emptyTreeView.backgroundColor = [UIColor blueColor];
    label1.backgroundColor = [UIColor redColor];
    label1.textAlignment = NSTextAlignmentCenter;
    label1.textColor = [UIColor blackColor];
    label1.font = [UIFont boldSystemFontOfSize:18];
    label1.numberOfLines = 0;
    label1.text = @"The Page Cannot be displayed.";
    label2.backgroundColor = [UIColor whiteColor];
    label2.textAlignment = NSTextAlignmentCenter;
    label2.textColor = [UIColor grayColor];
    label2.font = [UIFont systemFontOfSize:15];
    label2.numberOfLines = 0;
    label2.text = @"Please use this feature or contact your internal contact person directly.";
    [emptyTreeView addSubview:label1];
    [emptyTreeView addSubview:label2];
    [self.view addSubview:emptyTreeView];

    emptyTreeView.translatesAutoresizingMaskIntoConstraints = false;
    label1.translatesAutoresizingMaskIntoConstraints = false;
    label2.translatesAutoresizingMaskIntoConstraints = false;

    [NSLayoutConstraint activateConstraints:@[
        [emptyTreeView.leftAnchor constraintEqualToAnchor:self.view.safeAreaLayoutGuide.leftAnchor constant:20],
        [emptyTreeView.rightAnchor constraintEqualToAnchor:self.view.safeAreaLayoutGuide.rightAnchor constant:-10],
        [emptyTreeView.topAnchor constraintEqualToAnchor:self.view.safeAreaLayoutGuide.topAnchor constant:20],

        [label1.leftAnchor constraintEqualToAnchor:emptyTreeView.leftAnchor constant:20],
        [label1.rightAnchor constraintEqualToAnchor:emptyTreeView.rightAnchor constant:-20],
        [label1.topAnchor constraintEqualToAnchor:emptyTreeView.topAnchor constant:20],

        [label2.leftAnchor constraintEqualToAnchor:emptyTreeView.leftAnchor constant:20],
        [label2.rightAnchor constraintEqualToAnchor:emptyTreeView.rightAnchor constant:-20],
        [label2.topAnchor constraintEqualToAnchor:label1.bottomAnchor constant:20],

        [emptyTreeView.bottomAnchor constraintEqualToAnchor:label2.bottomAnchor constant:20]
    ]];
}

请注意 is 和约束。translatesAutoresizingMaskIntoConstraintsfalse

使用 Objective-C 以编程方式创建 UIView，以纵向和横向工作

Create UIView programmatically with Objective-C to work in both portrait and landscape

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