如何获取 UIAlertController 的框架宽度?

How do I get the frame width of UIAlertController?

我想获取 UIAlertController 框架的宽度,以便我可以指定 UIAlertController 附带的 UIPickerView 和 UIToolbar 的宽度。

我试过使用下面的语句来获取宽度。

alertPicker.view.frame.size.width

但是,宽度和viewController的一样:

self.view.frame.size.width

知道获取 UIAlertController 的宽度吗?非常感谢。

这是我的代码。

    UIAlertController *alertPicker = [UIAlertController alertControllerWithTitle:nil message:@"\n\n\n\n\n\n\n\n\n\n\n\n" preferredStyle:UIAlertControllerStyleActionSheet];

    CGRect pickerFrame = CGRectMake(8, 0, alertPicker.view.frame.size.width, self.view.frame.size.height/2);
    UIPickerView *pickerView = [[UIPickerView alloc] initWithFrame:pickerFrame];
    pickerView.showsSelectionIndicator = YES;
    pickerView.dataSource = self;
    pickerView.delegate = self;

    UIToolbar* pickerToolbar = [[UIToolbar alloc] initWithFrame: CGRectMake(2, 0, alertPicker.view.frame.size.width, 44)];
    UIBarButtonItem *doneBtn = [[UIBarButtonItem alloc] initWithTitle:@"Done" style:UIBarButtonItemStylePlain target:self action:@selector(doneBtnisClicked:)];
    UIBarButtonItem *flexSpace = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:nil];
    pickerToolbar.items = [[NSArray alloc] initWithObjects:flexSpace,doneBtn,nil];

   [alertPicker.view addSubview:pickerToolbar];
   [alertPicker.view addSubview:pickerView];

没有直接获取 UIAlertController 宽度的方法。 How to set height and width of a UIAlertController in IOS 8