在ViewController.h文件中用Objective-c语言纯代码写一个签到的日期界面

好的，下面是一个简单的签到日期界面代码：

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController

@property (nonatomic, strong) UILabel *dateLabel;
@property (nonatomic, strong) UIButton *checkInButton;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    self.view.backgroundColor = [UIColor whiteColor];
    
    self.dateLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, 100, self.view.frame.size.width, 30)];
    self.dateLabel.textAlignment = NSTextAlignmentCenter;
    [self.view addSubview:self.dateLabel];
    
    self.checkInButton = [[UIButton alloc] initWithFrame:CGRectMake(self.view.frame.size.width/2 - 50, 200, 100, 50)];
    [self.checkInButton setTitle:@"签到" forState:UIControlStateNormal];
    [self.checkInButton setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];
    self.checkInButton.backgroundColor = [UIColor blueColor];
    [self.checkInButton addTarget:self action:@selector(checkInButtonClicked) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:self.checkInButton];
}

- (void)checkInButtonClicked {
    // 在这里处理签到逻辑
}

@end

这个界面包括一个显示日期的标签和一个签到的按钮。当用户点击签到按钮时，你可以在 `checkInButtonClicked` 方法里处理签到逻辑，比如向服务器发送签到请求等。