Visual format language（1）

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原创最新推荐文章于 2026-04-08 09:35:52 发布 510 阅读 AI 写同款· GEO 优化 ›

龙芯3A5000开发板PMON升级UEFI固件实战指南固件是计算机硬件与操作系统之间的关键桥梁，负责初始化硬件并引导系统启动。其工作原理是在上电后执行自检、加载引导程序，最终将控制权移交操作系统。在国产化平台中，采用标准化的UEFI固件具有重要技术价值，它能提供图形化配置界面、统一硬件驱动模型，并支持安全启动等现代特性，从而显著提升硬件兼容性与系统管理效率。这一技术广泛应用于PC、服务器及嵌入式设备，尤其在需要运行银河麒麟等主流操作系统的龙芯开发板场景中，将传统PMON固件升级至UEFI，能实现更流畅的系统安装与更稳定的运行体验。本文基于固件升级与UEFI引导阅读详情

需求：添加一个控件，高度40，距离顶部，左边，右边 20

    // 1.创建控件
    UIView *blueView = [[UIView alloc] init];
    [self.view addSubview:blueView];
    blueView.backgroundColor = [UIColor blueColor];
    //不要将AutoresizingMask转为Autolayout的约束
    blueView.translatesAutoresizingMaskIntoConstraints = NO;
    
    // 2.添加约束
    //水平方向约束
    NSString *vfl = @"H:|-20-[blueView]-20-|";
    NSDictionary *views = @{@"blueView" : blueView};
    NSArray *constraints = [NSLayoutConstraint constraintsWithVisualFormat:vfl options:kNilOptions metrics:nil views:views];
    [self.view addConstraints:constraints];
    
    //垂直方向约束
    NSString *vfl2 = @"V:|-20-[blueView(40)]";
    NSArray *constraints2 = [NSLayoutConstraint constraintsWithVisualFormat:vfl2 options:kNilOptions metrics:nil views:views];
    [self.view addConstraints:constraints2];

优化后的代码：

    // 1.创建控件
    UIView *blueView = [[UIView alloc] init];
    [self.view addSubview:blueView];
    blueView.backgroundColor = [UIColor blueColor];
    //不要将AutoresizingMask转为Autolayout的约束
    blueView.translatesAutoresizingMaskIntoConstraints = NO;
    
    //间距
    NSNumber *margin = @20;
    
    // 2.添加约束
    //水平方向约束
    NSString *vfl = @"H:|-margin-[blueView]-margin-|";
    NSDictionary *views = NSDictionaryOfVariableBindings(blueView);
    NSDictionary *metrics = NSDictionaryOfVariableBindings(margin);
    NSArray *constraints = [NSLayoutConstraint constraintsWithVisualFormat:vfl options:kNilOptions metrics:metrics views:views];
    [self.view addConstraints:constraints];
    
    //垂直方向约束
    NSNumber *height = @40;
    NSString *vfl2 = @"V:|-margin-[blueView(height)]";
    NSDictionary *metrics2 =NSDictionaryOfVariableBindings(margin,height);
    NSArray *constraints2 = [NSLayoutConstraint constraintsWithVisualFormat:vfl2 options:kNilOptions metrics:metrics2 views:views];
    [self.view addConstraints:constraints2];

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