在Objective C iOS中显示多行文本的UITextField，Xcode10.2，iOS 13

// 在你的ViewController.h文件中
@property (nonatomic, strong) UITextView *textView;

// 在你的ViewController.m文件中
- (void)viewDidLoad {
    [super viewDidLoad];
    
    // 创建UITextView对象
    self.textView = [[UITextView alloc] initWithFrame:CGRectMake(20, 50, 200, 100)];
    
    // 设置UITextView属性
    self.textView.font = [UIFont systemFontOfSize:14];
    self.textView.textColor = [UIColor blackColor];
    
    // 添加UITextView到视图中
    [self.view addSubview:self.textView];
    
    // 设置UITextView的约束
    self.textView.translatesAutoresizingMaskIntoConstraints = NO;
    [NSLayoutConstraint activateConstraints:@[
        [self.textView.leadingAnchor constraintEqualToAnchor:self.view.leadingAnchor constant:20],
        [self.textView.trailingAnchor constraintEqualToAnchor:self.view.trailingAnchor constant:-20],
        [self.textView.topAnchor constraintEqualToAnchor:self.view.topAnchor constant:50],
        [self.textView.heightAnchor constraintEqualToConstant:100]
    ]];
}