UIAlertController 背景颜色 iOS10

Question

我为 iOS9 编写的代码运行得非常好：

UIAlertController* alert = [UIAlertController alertControllerWithTitle:@"Select source"
                                                                   message:nil
                                                            preferredStyle:UIAlertControllerStyleActionSheet];
    alert.view.backgroundColor = DARK_BLUE;
    alert.view.tintColor = NEON_GREEN;
    UIView *subview = alert.view.subviews.firstObject;
    UIView *alertContentView = subview.subviews.firstObject;
    alertContentView.backgroundColor = DARK_BLUE;
    alertContentView.layer.cornerRadius = 10;

我的观点是UIAlertController是继承自UIViewController，而UIViewController有属性UIView可以改变。这是有效的。现在，从 UIViewController 继承的那个视图有它自己的子视图，即显示为警报的 contentView。我可以在子视图数组中将其作为 firstObject 访问。现在，为什么发送背景颜色的消息不再起作用了？有人知道一些新的解决方案吗？

Answer 1

我用这个：

    UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"Alert!"
                                                                       message:@"Message of alert"
                                                                 preferredStyle:UIAlertControllerStyleAlert];

        UIAlertAction* defaultAction = [UIAlertAction actionWithTitle:@"Ok" 
                                                                style:UIAlertActionStyleDefault
                                                              handler:^(UIAlertAction * action) {

                                                                  //Your code
                                                              }];
        [alert addAction:defaultAction];

        UIView * topview = alert.view.subviews.firstObject;
        UIView * colorView = topview.subviews.firstObject;
        colorView.backgroundColor = [UIColor yellowColor];
        colorView.layer.cornerRadius = 10;
        [self presentViewController:alert animated:YES completion:nil];

Answer 2

对于遇到同样问题的每个人，我找到了解决方案：

UIAlertController.view 包含一个子视图，即只有 container.

该子视图包含子视图，其中包含两个它自己的子视图，一个是容器，另一个是模糊它的层。

因此，它需要在循环中遍历这两个子视图并更改两者的背景颜色。

完整代码：

UIAlertController* alert = [UIAlertController alertControllerWithTitle:@"Select source"
                                                                   message:nil
                                                            preferredStyle:UIAlertControllerStyleActionSheet];
    alert.view.tintColor = NEON_GREEN;

    UIView *firstSubview = alert.view.subviews.firstObject;

    UIView *alertContentView = firstSubview.subviews.firstObject;
    for (UIView *subSubView in alertContentView.subviews) { //This is main catch
        subSubView.backgroundColor = DARK_BLUE; //Here you change background
    }

Answer 3

在Swift3.0

let FirstSubview = alertController.view.subviews.first
    let AlertContentView = FirstSubview?.subviews.first
    for subview in (AlertContentView?.subviews)! {
        subview.backgroundColor = UIColor.black
        subview.layer.cornerRadius = 10
        subview.alpha = 1
        subview.layer.borderWidth = 1
        subview.layer.borderColor = UIColor.yellow.cgColor
    }

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