iOS: 学习笔记, 添加一个带界面约束的控制器

1. 创建一个空iOS应用程序(Empty Application).

2. 添加加控制器类. 修改控制器类的viewDidLoad

 1 - (void)viewDidLoad

 2 {

 3     [super viewDidLoad];

 4     //创建标题

 5     UILabel *header = [[UILabel alloc] init];

 6     header.text = @"欢迎来到我的世界!";

 7     header.textAlignment = NSTextAlignmentCenter;

 8     [self.view addSubview: header];

 9

10     self.statusLabel = [[UILabel alloc] init];

11     self.statusLabel.text = @"准备就绪!";

12     [self.view addSubview: self.statusLabel];

13

14

15     //添加自动布局约束

16     UILabel *statusLabel = self.statusLabel;

17     [header setTranslatesAutoresizingMaskIntoConstraints: NO];

18     [statusLabel setTranslatesAutoresizingMaskIntoConstraints: NO];

19

20     NSMutableArray *contraits = [NSMutableArray array];

21     NSMutableDictionary *metrics = [[NSMutableDictionary alloc] initWithObjectsAndKeys:@5, @"HPadding", @5, @"VPadding", @20, @"TopMargin", nil];

22     NSDictionary *views = NSDictionaryOfVariableBindings(header, statusLabel);

23     [contraits addObjectsFromArray:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-HPadding-[header]-HPadding-|" options:0 metrics:metrics views:views]];

24     [contraits addObjectsFromArray:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-HPadding-[statusLabel]-HPadding-|" options:0 metrics:metrics views:views]];

25     [contraits arrayByAddingObjectsFromArray:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-HPadding-[statusLabel]-HPadding-|" options:0 metrics:metrics views:views]];

26     [contraits addObjectsFromArray:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|-TopMargin-[header]-(>=0)-[statusLabel]-VPadding-|" options:0 metrics:metrics views:views]];

27

28     [self.view addConstraints: contraits];

29

30 }

3. 修改AppDelegate.m文件

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions

{

    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];

    // Override point for customization after application launch.

    self.window.backgroundColor = [UIColor whiteColor];

//加入控制器

    self.window.rootViewController = [[DemoViewController alloc] initWithNibName:nil bundle:nil];
[self.window makeKeyAndVisible];

    return YES;

}

4. 运行程序, 得到如下效果

iOS: 学习笔记, 添加一个带界面约束的控制器,布布扣,bubuko.com