Xcode8 iOS9 UIAlertController textfield disapear（iOS8＆amp; 10是正常的）

Question

Xcode 8 iOS9 UIAlertController文本消失。 在从Xcode7迁移到Xcode8之前，在iOS9上运行应用程序时没有任何问题。

1. iOS9 UIAlertController With UITextfield
2. iOS10 UIAlertController With UITextfield

有没有人有这个问题？

UIAlertController * alertController = [UIAlertController alertControllerWithTitle：@“mile”message：nil preferredStyle：UIAlertControllerStyleAlert];

UIAlertAction *cancelAction = [UIAlertAction actionWithTitle:getLocalizationString(@"cancel") style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) {
      [[NSNotificationCenter defaultCenter] removeObserver:self name:UITextFieldTextDidChangeNotification object:nil];
}];
[alertController addAction:cancelAction];

@weakify(alertController);
@weakify(self);
UIAlertAction *okAction = [UIAlertAction actionWithTitle:getLocalizationString(@"ok") style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
      [[NSNotificationCenter defaultCenter] removeObserver:self name:UITextFieldTextDidChangeNotification object:nil];
    @strongify(alertController);
    @strongify(self);
    UITextField *textField = alertController.textFields.firstObject;
    self.totalMileage = textField.text;
    self.mileageLabel.text = self.totalMileage;
    if (self.start2DriveDateTime&&![self.start2DriveDateTime isEqualToString:@""]) {
        [self getRecommendMaintenanceList];
    }
}];
okAction.enabled = (self.totalMileage&&![self.totalMileage isEqualToString:@""]);
[alertController addAction:okAction];


[alertController addTextFieldWithConfigurationHandler:^(UITextField *textField){
    @strongify(self);
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(alertTextFieldDidChange:) name:UITextFieldTextDidChangeNotification object:textField];
    textField.placeholder = @"mile";
    textField.keyboardType =UIKeyboardTypeNumberPad;
    textField.text = self.totalMileage;
    textField.delegate = self;
}];
[self.navigationController presentViewController:alertController animated:YES completion:nil];