ios - 我需要图像的中心在屏幕中心

Question

无论位置如何，如何将图像固定在屏幕中央我需要在任何屏幕中间固定指南针

这是我的代码

_backgroundImageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"background.jpg"]];

    [self.view addSubview:_backgroundImageView];

    CGPoint centerImageView = _backgroundImageView.center;
    centerImageView.x = self.view.center.x;
    _backgroundImageView.center = centerImageView;

但是图像固定在左侧，我不需要根据屏幕居中放置的位置

现在只有正确的位置会变化

现在只有正确的位置会变化

我需要图像的中心在屏幕中心

Answer 1

这是一种方法:

在viewDidLoad上:

_backgroundImageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"background.jpg"]];
[self.view addSubview:_backgroundImageView];

CGRect bgImageFrame = _backgroundImageView.frame;
bgImageFrame.origin.x = (self.view.frame.size.width / 2.0) - (bgImageFrame.size.width / 2.0);
bgImageFrame.origin.y = (self.view.frame.size.height / 2.0) - (bgImageFrame.size.height / 2.0);
_backgroundImageView.frame = bgImageFrame;

那么每次屏幕旋转时都会调用此方法:

- (void)viewWillTransitionToSize:(CGSize)size withTransitionCoordinator:(id<UIViewControllerTransitionCoordinator>)coordinator {
    [coordinator animateAlongsideTransition:^(id  _Nonnull context) {

        CGRect bgImageFrame = _backgroundImageView.frame;
        bgImageFrame.origin.x = (self.view.frame.size.width / 2.0) - (bgImageFrame.size.width / 2.0);
        bgImageFrame.origin.y = (self.view.frame.size.height / 2.0) - (bgImageFrame.size.height / 2.0);
        _backgroundImageView.frame = bgImageFrame;

    } completion:nil];
}