将视图居中于视图控制器的中心

Question

我试图在加载 table 视图时显示动画微调器。

loadingView = [[UIView alloc] initWithFrame:CGRectMake(75, 155, 170, 170)];
loadingView.backgroundColor = [UIColor colorWithRed:0 green:0 blue:0 alpha:0.5];
loadingView.clipsToBounds = YES;
loadingView.layer.cornerRadius = 10.0;

activityView = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
activityView.frame = CGRectMake(65, 40, activityView.bounds.size.width, activityView.bounds.size.height);
[loadingView addSubview:activityView];

loadingLabel = [[UILabel alloc] initWithFrame:CGRectMake(20, 115, 130, 22)];
loadingLabel.backgroundColor = [UIColor clearColor];
loadingLabel.textColor = [UIColor whiteColor];
loadingLabel.adjustsFontSizeToFitWidth = YES;
loadingLabel.textAlignment = NSTextAlignmentCenter;
loadingLabel.text = @"Loading...";
[loadingView addSubview:loadingLabel];

[self.view addSubview:loadingView];
[activityView startAnimating];

我在 loadingView 中嵌入了 UIActivityIndicatorView。我面临的问题是：

加载视图不在视图控制器的中心。
我试图将加载视图居中到视图控制器的中心，UIActivityIndicatorView 必须位于加载视图的中心，但它并没有像我期望的那样居中。

Answer 1

当视图控制器布置子视图时，您应该将其居中。

对于视图控制器，viewDidLayoutSubviews 是一个很好的地方：

- (void)viewDidLayoutSubviews {
  [super viewDidLayoutSubviews];
  self.activityView.center = CGPointMake(CGRectGetWidth(self.loadingView.frame) / 2, CGRectGetHeight(self.loadingView.frame) / 2);
  self.loadingView.center = CGPointMake(CGRectGetWidth(self.view.frame) / 2, CGRectGetHeight(self.view.frame) / 2);
}

Answer 2

在 ViewDidLoad 中添加有效的代码：

[self.view addSubview: loadingView];
loadingView .center = CGPointMake(CGRectGetWidth(self.view.frame) / 2, CGRectGetHeight(self.view.frame) / 2);

Answer 3

设置框架：

int width = 170;
loadingView = [[UIView alloc] initWithFrame:CGRectMake(([UIScreen mainScreen].bounds.size.width/2) - (width)/2, ([UIScreen mainScreen].bounds.size.height/2) - (height)/2, width, width)];
activityView.frame = CGRectMake((loadingView.frame.size.width/2) -(activityView.bounds.size.width/2), (loadingView.frame.size.height/2) - (activityView.bounds.size.height/2) - 11, activityView.bounds.size.width, activityView.bounds.size.height);
loadingLabel = [[UILabel alloc] initWithFrame:CGRectMake((loadingView.frame.size.width/2) - 65, loadingView.frame.size.height - 25, 130, 22)];

或

loadingView.center = CGPointMake(([UIScreen mainScreen].bounds.size.width/2), ([UIScreen mainScreen].bounds.size.height/2) );

将视图居中于视图控制器的中心

Centring a view at the centre of view controller

ios

objective-c

uiactivityindicatorview