动态调整Top Space

Adjust Top Space.m

/*
在nib文件中设置autolayout,设置 parentView 和 childView 之间的 top space,然后根据横竖屏来调整 top space大小
*/

-(void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation  duration:(NSTimeInterval)duration
{
    if(UIInterfaceOrientationIsLandscape(toInterfaceOrientation)){
        [self adjustTopSpace:100.0f];
    }else{
        [self adjustTopSpace:300.0f];
    }
}

- (void)adjustTopSpace:(CGFloat)contant
{
    NSArray *constraints = [parentView.constraints copy];
    for (NSLayoutConstraint *constraint in constraints) {
        
        id firstItem = constraint.firstItem;
        NSLayoutAttribute fa = constraint.firstAttribute;
        id secondItem = constraint.secondItem;
        NSLayoutAttribute sa = constraint.secondAttribute;
        NSLayoutRelation rl = constraint.relation;
        CGFloat mp = constraint.multiplier;
        CGFloat c = constraint.constant;
        
        Logger(@"======begin======= ");
        
        Logger(@"first item: %@",firstItem);
        Logger(@"second item: %@",secondItem);
        Logger(@"first attri: %ld",fa);
        Logger(@"second attri: %ld",sa);
        Logger(@"multiplier : %f",mp);
        Logger(@"constant: %f",c);
        Logger(@"relation: %ld",rl);
        
        Logger(@"=======end======= ");
        
        if (childView == firstItem && fa == NSLayoutAttributeTop && parentView == secondItem && sa == NSLayoutAttributeTop) {
            NSLayoutConstraint *fixedConstraint = [NSLayoutConstraint constraintWithItem:firstItem attribute:constraint.firstAttribute relatedBy:constraint.relation toItem:secondItem attribute:constraint.secondAttribute multiplier:constraint.multiplier constant:contant];

            [parentView removeConstraint:constraint];
            [parentView addConstraint:fixedConstraint];
        }
    }
}