关于IOS的Autolayout代码编写使用

- (void)viewDidLoad

{
UIButton *btn1=[UIButton buttonWithType:UIButtonTypeRoundedRect];

[btn1 setTitle:@"Click Me" forState:UIControlStateNormal];

[btn1 setTranslatesAutoresizingMaskIntoConstraints:NO];//标记是否自动布局

[self.view addSubview:btn1];

UIButton *btn2=[UIButton buttonWithType:UIButtonTypeRoundedRect];

[btn2 setTitle:@"Click Me Please" forState:UIControlStateNormal];

[btn2 setTranslatesAutoresizingMaskIntoConstraints:NO];//标记是否自动布局

[self.view addSubview:btn2];

NSDictionary *views=NSDictionaryOfVariableBindings(btn1,btn2);

[self.view addConstraints:

[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-(==50)-[btn1(100)]"

options:0

metrics:nil

views:views]];

[self.view addConstraints:

[NSLayoutConstraint constraintsWithVisualFormat:@"V:|-(==50)-[btn1(30)]"

options:0

metrics:nil

views:views]];

[self.view addConstraints:

[NSLayoutConstraint constraintsWithVisualFormat:@"H:[btn2(==150)]" </span><span style="font-family: 'Comic Sans MS'; "><span style="font-size:12px;">//H=Horizontal，水平方向，同时设定控件宽度</span></span><span
style="font-size:14px;">

options:0

metrics:nil

views:views]];

[self.view addConstraints:

[NSLayoutConstraint constraintsWithVisualFormat:@"V:|-(>=200)-[btn2(==btn1)]" //V=Vertical,垂直方向，同时设定控件高度

options:0

metrics:nil

views:views] ];

//注意AddConstraints和AddConstraint之间的区别，一个添加的参数是(NSArray *)，一个是(NSLayoutConstraint *)

[self.view addConstraint:

[NSLayoutConstraint constraintWithItem:btn2

attribute:NSLayoutAttributeLeft

relatedBy:NSLayoutRelationEqual

toItem:btn1

attribute:NSLayoutAttributeRight

multiplier:1

constant:10]];

[self.view addConstraint:

[NSLayoutConstraint constraintWithItem:btn2

attribute:NSLayoutAttributeTop //要设定的属性

relatedBy:NSLayoutRelationGreaterThanOrEqual //大于还是小于相对的View的值

toItem:btn1 //相对于某个View或者控件

attribute:NSLayoutAttributeTop //指定要设定的关联View的属性

multiplier:1 //因子值

constant:0]];

[super viewDidLoad];

// Do any additional setup after loading the view, typically
from a nib.

}

转载自：http://blog.csdn.net/mobilecode/article/details/8842379