AutoLayout NSLayoutConstraint

- (void)viewDidLoad

{

    [superviewDidLoad];

   UILabel *label = [[UILabelalloc]init];

    label.text =@"AutoLayout";

    label.backgroundColor = [UIColorlightGrayColor];

    

    self.view.translatesAutoresizingMaskIntoConstraints = NO;

    label.translatesAutoresizingMaskIntoConstraints =NO;

    

    [self.viewaddSubview:label];

    

    

    //AutoLayout, 创建约束对象

    //view1.attr1 = view2.attr2 * multiplier + constant;

    NSLayoutConstraint *constraint1 = [NSLayoutConstraintconstraintWithItem:label attribute:NSLayoutAttributeBottomrelatedBy:NSLayoutRelationEqualtoItem:self.viewattribute:NSLayoutAttributeBottommultiplier:1constant:-10];

    NSLayoutConstraint *constraint2 = [NSLayoutConstraintconstraintWithItem:label attribute:NSLayoutAttributeRightrelatedBy:NSLayoutRelationEqualtoItem:self.viewattribute:NSLayoutAttributeRightmultiplier:1constant:-10];

    

    //给控件(子视图)加约束

    [self.viewaddConstraints:@[constraint1, constraint2]];

    

    

}