使用Objective-C以編程方式創建UIView以在縱向和橫向作業

我必須在目標 c 中創建一個視圖，上面有兩個標簽，label1 有單行，label2 是基于內容的多行。

根據標簽中的內容，我想調整視圖高度，我該怎么做？

視圖的寬度應該是 20 左右到螢屏寬度，下面的代碼我可以縱向顯示，但在橫向顯示它不正確，它在右側裁剪。我怎樣才能顯示正確的 20 風景？

肖像

風景

    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];

我做錯了什么嗎？

uj5u.com熱心網友回復：

一些觀察：

1. 不要在viewDidLayoutSubviews. 這僅用于調整frame值。

2. 如果你參考self.view，參考它bounds，而不是它的frame。前者用于self.view. 后者在其父視圖的坐標系中（現在可能不會引入任何差異，但只是錯誤的坐標系。

3. 如果您希望視圖在旋轉時調整大小，請設定它的autoresizingMask，例如

   emptyTreeView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleBottomMargin;
   

   或者

   emptyTreeView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleBottomMargin;
   

4. 如今，設定幀值和自動調整蒙版大小有點過時了。我們通常會使用約束，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]
       ]];
   }
   

   注意translatesAutoresizingMaskIntoConstraints是false和約束。

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