iphone - 在 iOS 的 UIView 上加载时如何为 UIActivityIndi​​cator 设置灰色背景

Question

我目前有一个 UIActivityIndi​​cator 出现在屏幕上一两秒钟。我想将背景设置为灰色，因为它出现在屏幕上，但我不知道该怎么做...

到目前为止，这是我初始化指标的方式。

- (void)viewDidLoad
{
//...

    activity = [[UIActivityIndicatorView alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 32.0f, 32.0f)];
    [activity setCenter:CGPointMake(160.0f, 208.0f)];
    [activity setActivityIndicatorViewStyle:UIActivityIndicatorViewStyleGray];

    [self.tableView addSubview:activity];

    [activity startAnimating];

    [activity performSelector:@selector(stopAnimating) withObject:nil afterDelay:1.0];


}

如有任何帮助，我们将不胜感激。

Answer 1

不需要单独的 View 。这是一个简单的机制:

    UIActivityIndicatorView *activity = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];

    self.activityIndicatorView = activity;
    // make the area larger
    [activity setFrame:self.view.frame;
    // set a background color
    [activity.layer setBackgroundColor:[[UIColor colorWithWhite: 0.0 alpha:0.30] CGColor]];
    CGPoint center = self.view.center;
    activity.center = center;
    [activity release];