1.上下左右

[tipsLabel setTranslatesAutoresizingMaskIntoConstraints:NO];{        id view1 = tipsLabel;        id view2 = self;        //子view的上边缘离父view的上边缘                NSLayoutConstraint *contraint1 = [NSLayoutConstraint constraintWithItem:view1 attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:view2 attribute:NSLayoutAttributeTop multiplier:1.0 constant:0.0];                //子view的左边缘离父view的左边缘                NSLayoutConstraint *contraint2 = [NSLayoutConstraint constraintWithItem:view1 attribute:NSLayoutAttributeLeft relatedBy:NSLayoutRelationEqual toItem:view2 attribute:NSLayoutAttributeLeft multiplier:1.0 constant:0.0];                //子view的下边缘离父view的下边缘                NSLayoutConstraint *contraint3 = [NSLayoutConstraint constraintWithItem:view1 attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual toItem:view2 attribute:NSLayoutAttributeBottom multiplier:1.0 constant:-btnHeight];                //子view的右边缘离父view的右边缘                NSLayoutConstraint *contraint4 = [NSLayoutConstraint constraintWithItem:view1 attribute:NSLayoutAttributeRight relatedBy:NSLayoutRelationEqual toItem:view2 attribute:NSLayoutAttributeRight multiplier:1.0 constant:0.0];                //把约束添加到父视图上                NSArray *array = [NSArray arrayWithObjects:contraint1, contraint2, contraint3, contraint4, nil,nil];                [self addConstraints:array];    }

宽高

[imgv setTranslatesAutoresizingMaskIntoConstraints:NO];        {        id view1 = imgv;        id view2 = self.view;        id viewNil = nil;        //                NSLayoutConstraint *contraint1 = [NSLayoutConstraint constraintWithItem:view1 attribute:NSLayoutAttributeWidth relatedBy:NSLayoutRelationEqual toItem:viewNil attribute:NSLayoutAttributeWidth multiplier:1.0 constant:size.width];        [imgv addConstraint:contraint1];        //                NSLayoutConstraint *contraint2 = [NSLayoutConstraint constraintWithItem:view1 attribute:NSLayoutAttributeHeight relatedBy:NSLayoutRelationEqual toItem:viewNil attribute:NSLayoutAttributeHeight multiplier:1.0 constant:size.height];         [imgv addConstraint:contraint2];        //子view的下边缘离父view的下边缘                NSLayoutConstraint *contraint3 = [NSLayoutConstraint constraintWithItem:view1 attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual toItem:view2 attribute:NSLayoutAttributeBottom multiplier:1.0 constant:0.0];                //子view的右边缘离父view的右边缘                NSLayoutConstraint *contraint4 = [NSLayoutConstraint constraintWithItem:view1 attribute:NSLayoutAttributeRight relatedBy:NSLayoutRelationEqual toItem:view2 attribute:NSLayoutAttributeRight multiplier:1.0 constant:0.0];                //把约束添加到父视图上                NSArray *array = [NSArray arrayWithObjects:contraint3, contraint4, nil,nil];                [self.view addConstraints:array];                    }