ios - How to center a UIButton after device is rotated in iOS

Question

I have created a UIButton programmatically and horizontally centered it using the following code

    button.center = CGPointMake(self.view.center.x, 50);

When device is rotated, it's no longer in the center. How can I fix this problem? Thanks in advance.

Answer 1

Kevin 是正确的，但更好的解决方案是在视图控制器的willAnimateRotationToInterfaceOrientation:duration:方法中设置按钮的中心。

- (void)willAnimateRotationToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation duration:(NSTimeInterval)duration
{
    button.center = CGPointMake(self.view.center.x, 50);
}

他使用了这种didRotateFromInterfaceOrientation:fromInterfaceOrientation 方法，正如 Apple 文档所述，“这种方法可能用于重新启用视图交互、重新开始媒体播放或打开昂贵的绘图或实时更新。 ”

在布置子视图的情况下，willAnimateRotationToInterfaceOrientation:duration:将提供更平滑的过渡，因为它是从旋转的动画块中调用的。

Answer 2

- (void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation
{
    button.center = CGPointMake(self.view.center.x, 50);
}