为什么我的 UIPickerview 在 UIAlertcontroller 中不起作用？

Question

我需要在警报视图控制器中显示一个选择器视图，为此我遵循的是

//对于alertview控制器

let alertController = UIAlertController(title: "Hey!", message: "MESSAGE?", preferredStyle: .Alert)
let defaultAction = UIAlertAction(title: "OK", style: .Default, handler: nil)
alertController.addAction(defaultAction)

//对于pickerview

let monthlyStatement = UIStoryboard(name: "Second", bundle: nil).instantiateViewControllerWithIdentifier("MonthlyStatement")
monthlyStatement.view.frame = CGRectMake(0, 0, 280, 260)
alertController.view.addSubview(monthlyStatement.view)
presentViewController(alertController, animated: true, completion: nil) 

monthlyStatement 选择器视图将完美显示，但不会滚动，

当我尝试单击（选择器视图/选择器视图组件）时，它会立即关闭我的警报视图控制器。 那么如何解决这些问题。 提前谢谢你

Answer 1

你可以这样实现。

 func showPickerInActionSheet(sentBy: String) {
    var title = "picker"
    var message = "Picker controller";
    var alert = UIAlertController(title: title, message: message, preferredStyle: UIAlertControllerStyle.ActionSheet);
    alert.modalInPopover = true;


    //Create a frame (placeholder/wrapper) for the picker and then create the picker
    var pickerFrame: CGRect = CGRectMake(17, 52, 270, 100); // CGRectMake(left), top, width, height) - left and top are like margins
    var picker: UIPickerView = UIPickerView(frame: pickerFrame);

    /* If there will be 2 or 3 pickers on this view, I am going to use the tag as a way
    to identify them in the delegate and datasource. /* This part with the tags is not required.
    I am doing it this way, because I have a variable, witch knows where the Alert has been invoked from.*/
    if(sentBy == "profile"){
        picker.tag = 1;
    } else if (sentBy == "user"){
        picker.tag = 2;
    } else {
        picker.tag = 0;
    }

    //set the pickers datasource and delegate
    picker.delegate = self;
    picker.dataSource = self;

    //Add the picker to the alert controller
    alert.view.addSubview(picker);

    //Create the toolbar view - the view witch will hold our 2 buttons 
    var toolFrame = CGRectMake(17, 5, 270, 45);
    var toolView: UIView = UIView(frame: toolFrame);

    //add buttons to the view
    var buttonCancelFrame: CGRect = CGRectMake(0, 7, 100, 30); //size & position of the button as placed on the toolView

    //Create the cancel button & set its title
    var buttonCancel: UIButton = UIButton(frame: buttonCancelFrame);
    buttonCancel.setTitle("Cancel", forState: UIControlState.Normal);
    buttonCancel.setTitleColor(UIColor.blueColor(), forState: UIControlState.Normal);
    toolView.addSubview(buttonCancel); //add it to the toolView

    //Add the target - target, function to call, the event witch will trigger the function call
    buttonCancel.addTarget(self, action: "cancelSelection:", forControlEvents: UIControlEvents.TouchDown);


    //add buttons to the view
    var buttonOkFrame: CGRect = CGRectMake(170, 7, 100, 30); //size & position of the button as placed on the toolView

    //Create the Select button & set the title
    var buttonOk: UIButton = UIButton(frame: buttonOkFrame);
    buttonOk.setTitle("Select", forState: UIControlState.Normal);
    buttonOk.setTitleColor(UIColor.blueColor(), forState: UIControlState.Normal);
    toolView.addSubview(buttonOk); //add to the subview

    //Add the tartget. In my case I dynamicly set the target of the select button
    if(sentBy == "profile"){
        buttonOk.addTarget(self, action: "saveProfile:", forControlEvents: UIControlEvents.TouchDown);
    } else if (sentBy == "user"){
        buttonOk.addTarget(self, action: "saveUser:", forControlEvents: UIControlEvents.TouchDown);
    }

    //add the toolbar to the alert controller
    alert.view.addSubview(toolView);

    self.presentViewController(alert, animated: true, completion: nil);
}

func saveProfile(sender: UIButton){
    // Your code when select button is tapped

}

func saveUser(sender: UIButton){
    // Your code when select button is tapped
}

func cancelSelection(sender: UIButton){
    println("Cancel");
    self.dismissViewControllerAnimated(true, completion: nil);
    // We dismiss the alert. Here you can add your additional code to execute when cancel is pressed
}

// returns number of rows in each component..
func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int{
    if(pickerView.tag == 1){
        return self.profilesList.count;
    } else if(pickerView.tag == 2){
        return self.usersList.count;
    } else  {
        return 0;
    }
}

// Return the title of each row in your picker ... In my case that will be the profile name or the username string
func pickerView(pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String! {
    if(pickerView.tag == 1){

            var selectedProfile: Profiles = self.profilesList[row] as Profiles;
            return selectedProfile.profileName;

    } else if(pickerView.tag == 2){

            var selectedUser: Users = self.usersList[row] as Users;
            return selectedUser.username;

    } else  {

        return "";

    }

}

func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
    if(pickerView.tag == 1){
            var choosenProfile: Profiles = profilesList[row] as Profiles;
            self.selectedProfile = choosenProfile.profileName;
    } else if (pickerView.tag == 2){
            var choosenUser: Profiles = usersList[row] as Users;
            self.selectedUsername = choosenUser.username;
    }

}

Answer 2

alertController.view.addSubview(monthlyStatement.view)

永远永远不要那样做。您无需手动修改警报控制器的视图。它不是为此而设计的。如果您需要在警报中显示选择器，请制作您自己的类似警报的显示视图控制器。然后，您将完全控制给您带来麻烦的界面和解除行为。