第30月第18天 autolayout代码

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];

    }

https://www.jianshu.com/p/3c2f41e2ef6e