使用自动布局读取UI正确的框架

Question

I have a UIViewController with UIScrollView inside. The scroll view automatically adjust its frame according with device screen. My problem is that in the code I can't read the correct frame of scroll view. self.scrollView.frame always return {{0, 0}, {600, 600}} that's the default size of view controller in Interface Builder xib.

I have tried in viewDidLoad and in loadView methods but the frame is still {{0, 0}, {600, 600}} .

- (void)viewDidLoad {

    [super viewDidLoad];

    self.scrollView.pagingEnabled = YES;
    self.scrollView.delegate = self;

    NSLog(@"%@",NSStringFromCGRect(self.scrollView.frame));
}

Ideas ?

Answer 1

您可以在viewController的-(void)viewDidLayoutSubviews方法中获得正确的帧

Answer 2

when ever you need correct frame after apply layout constraints
write below two lines

[self.view setNeedsLayout];
[self.view layoutIfNeeded];