How to use UIAlertController to replace UIActionSheet?

Question

I am maintaining an old iOS project which based on SDK 6.0.

A method on this project called

-(void) showComboBox:(UIView*)view:withOptions:(NSDictionary*)options

is used to show a combo box. To achieve the goal, it used UIActionSheet, which is deprecated on iOS8.

My solution is like this:

        if (floor(NSFoundationVersionNumber) > NSFoundationVersionNumber10_8) {
        UIAlertController* alertController = [UIAlertController 
           alertControllerWithTitle:@"title" 
           message:@"message" 
           preferredStyle:UIAlertControllerStyleActionSheet];

        UIAlertAction* item = [UIAlertAction actionWithTitle:@"item" 
           style:UIAlertActionStyleDefault 
           handler:^(UIAlertAction *action) {
            //do something here 
            //inform the selection to the WebView 
            ...
            [alertController dismissViewControllerAnimated:YES completion:nil];
        }];

        UIAlertAction* cancelAction = [UIAlertAction actionWithTitle:@"Cancel" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) {
            [alertController dismissViewControllerAnimated:YES completion:nil];
        }];

        [alertController addAction:item];
        [alertController addAction:cancelAction];
        //I am not sure whether it's the right way
        if ([view.nextResponder isKindOfClass:UIViewController.class]) {
            UIViewController* vc = (UIViewController*)view.nextResponder;
            [vc presentViewController:alertController animated:YES completion:nil];
        }

Is that a proper solution?

This is what I mostly concern about: UIAlertController needs to be added to a UIViewController but I can only get the pointer of the UIView, so I used view.nextResponder to get what I want, but it's that a good way?

Ibiza

Answer 1

I have used following code to show action sheet using UIAlertViewController and it works perfect.

Swift

let alert = UIAlertController(title: "Action Title", message: "Action Message", preferredStyle: .actionSheet)
let action = UIAlertAction(title: "Item", style: .default) {
    UIAlertAction in
    // Write your code here
}
alert.addAction(action)

let cancelAction = UIAlertAction(title: "Cancel", style: .cancel) {
    UIAlertAction in
    // It will dismiss action sheet
}
alert.addAction(cancelAction)
self.present(alert, animated: true, completion: nil)

Objective C

- (IBAction)buttonClicked:(id)sender {

    UIAlertController *actionSheet = [UIAlertController alertControllerWithTitle:@"Action Sheet" message:@"Using the alert controller" preferredStyle:UIAlertControllerStyleActionSheet];

    [actionSheet addAction:[UIAlertAction actionWithTitle:@"Cancel" style:UIAlertActionStyleCancel handler:^(UIAlertAction *action) {

        // Cancel button tappped.
        [self dismissViewControllerAnimated:YES completion:^{
        }];
    }]];

    [actionSheet addAction:[UIAlertAction actionWithTitle:@"Delete" style:UIAlertActionStyleDestructive handler:^(UIAlertAction *action) {

        // Distructive button tapped.
        [self dismissViewControllerAnimated:YES completion:^{
        }];
    }]];

    [actionSheet addAction:[UIAlertAction actionWithTitle:@"OK" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) {

        // OK button tapped.

        [self dismissViewControllerAnimated:YES completion:^{
        }];
    }]];

    // Present action sheet.
    [self presentViewController:actionSheet animated:YES completion:nil];
}

Edit:

You need to get UIViewController object here. You can set global variable or call a delegate method, or you can use notification to get view controller object in this code.

and last line in above code will be like.

[self.viewController presentViewController:actionSheet animated:YES completion:nil];

self.viewController is a global variable which will be set before you actually get this view.

Because the approach you are following now using view.nextResponder. I'm afraid that it may not work.

Transfuse

Almost the same, except for a little difference: I can't get the pointer of UIViewController directly so I have to user UIView.nextResponder instead, and I want to know if it's right. – Ibiza

What is view in your code? Is it a subview of any view controller? – Transfuse

Actually it's used by WebView to popup a combo box, like phonegap. – Ibiza

But both setting a global variable or calling a delegate method mean a lot of changes, and the project would look weird. Why using view.nextResponder would be a bad idea? I've had a few tests and it seems work fine. – Ibiza

It's all about application architecture. If you successfully get view controller object than it's fine. But how ever make sure the next responder is always a view controller. – Transfuse

It works fine on iOS8, but I did some tests on iOS7 and it didn't work :( – Ibiza

Dude! UIAlertController is available for iOS 8.0 - And Explain how it fails? What is the point? – Transfuse

Er...I just didn't remember that UIAlertController is not for iOS7, my bad. – Ibiza

@Kampai Thanks for your answer. It is very simple and easy to understand. It save my time. – Linger

Answer 2

I have used action sheet for changing profile picture. I followed Kampai approach, just removed dismissviewController call since it was kicking me out of a view when pressing Cancel or photo selection view

UIAlertController *actionSheet = [UIAlertController alertControllerWithTitle:nil message:nil preferredStyle:UIAlertControllerStyleActionSheet];

[actionSheet addAction:[UIAlertAction actionWithTitle:@"Cancel" style:UIAlertActionStyleCancel handler:^(UIAlertAction *action) {

    // Cancel button tappped do nothing.

}]];

[actionSheet addAction:[UIAlertAction actionWithTitle:@"Take photo" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) {

    // take photo button tapped.
    [self takePhoto];

}]];

[actionSheet addAction:[UIAlertAction actionWithTitle:@"Choose photo" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) {

    // choose photo button tapped.
    [self choosePhoto];

}]];

[actionSheet addAction:[UIAlertAction actionWithTitle:@"Delete Photo" style:UIAlertActionStyleDestructive handler:^(UIAlertAction *action) {

    // Distructive button tapped.
    [self deletePhoto];

}]];

Bountiful

Answer 3

Swift update -

    let actionSheet = UIAlertController.init(title: "Please choose a source type", message: nil, preferredStyle: .actionSheet)
    actionSheet.addAction(UIAlertAction.init(title: "Take Photo", style: UIAlertActionStyle.default, handler: { (action) in
        self.openCamera()
    }))
    actionSheet.addAction(UIAlertAction.init(title: "Choose Photo", style: UIAlertActionStyle.default, handler: { (action) in
        self.showPhotoLibrary()
    }))
    actionSheet.addAction(UIAlertAction.init(title: "Cancel", style: UIAlertActionStyle.cancel, handler: { (action) in
        // self.dismissViewControllerAnimated(true, completion: nil) is not needed, this is handled automatically,
         //Plus whatever method you define here, gets called,
        //If you tap outside the UIAlertController action buttons area, then also this handler gets called.
    }))
    //Present the controller
    self.present(actionSheet, animated: true, completion: nil)

Overload

Answer 4

Swift 4

        let alert = UIAlertController(title: "Select One", message: nil, preferredStyle: UIAlertControllerStyle.actionSheet)
        alert.addAction(UIAlertAction(title: "Cancel", style: UIAlertActionStyle.cancel, handler: nil))
        alert.addAction(UIAlertAction(title: "Export", style: UIAlertActionStyle.default, handler: { (action) in

            // TODO: Export wordlist

        }))
        alert.addAction(UIAlertAction(title: "Import", style: UIAlertActionStyle.default, handler: { (action) in

            // TODO: Import wordlist
        }))

        self.present(alert, animated: true, completion: nil)

Leilaleilah

Answer 5

You can use view.window.rootViewController instead. If you don't care about presenter it is fine.

Cameral

Answer 6

While it may look very simple, there is a nasty issue with using UIAlertController. It is memory leaks prone. In order to test if you have the issue, just put a breakpoint at your view controller's dealloc method and see if it's deallocated properly.

I was looking for a solution for quite some time and here is how I use an alert controller in my app.

+ (void)alertWithPresenting:(UIViewController *)presenting title:(NSString *)title
                       text:(NSString *)text buttons:(NSArray *)buttons
                    handler:(void (^)(UIAlertAction *action, NSUInteger index))handler
{
        UIAlertController *alert = [UIAlertController
                                    alertControllerWithTitle:title message:text
                                    preferredStyle:UIAlertControllerStyleAlert];
        __weak __typeof(alert) weakAlert = alert;
        for (NSString *title in buttons) {
                UIAlertActionStyle style = UIAlertActionStyleDefault;
                if ([title isEqualToString:[L10n cancelButton]])
                        style = UIAlertActionStyleCancel;
                else if ([title isEqualToString:[L10n deleteButton]])
                        style = UIAlertActionStyleDestructive;
                else if ([title isEqualToString:[L10n archiveButton]])
                        style = UIAlertActionStyleDestructive;

                UIAlertAction *action = [UIAlertAction actionWithTitle:title style:style handler:^(UIAlertAction *action) {
                        if (handler != nil)
                                handler(action, [buttons indexOfObject:action.title]);
                        [weakAlert dismissViewControllerAnimated:YES completion:nil];
                }];
                [alert addAction:action];
        }
        [presenting presentViewController:alert animated:YES completion:nil];
}

This is not all. Here is an example of how you use it in your view controller. In my case its tableview with search, so presenting controller may be different.

- (void) deleteCases:(NSArray *)selectedRows
{
        NSString *text = NSLocalizedStringWithDefaultValue(@"cases.delete.alert.text",
                                                           @"Localizable",  [NSBundle mainBundle],
                                                           @"Deleted cases cannot be restored. Continue with delete?",
                                                           @"Delete alert text");
        NSString *title = NSLocalizedStringWithDefaultValue(@"cases.delete.alert.title",
                                                            @"Localizable",  [NSBundle mainBundle],
                                                            @"Delete cases", @"Detete alert title");
        UIViewController *presenting = self.searchController.active ? self.searchController : self;
        __weak __typeof(presenting) weakPresenting = presenting;
        __weak __typeof(self) weakSelf = self;
        [YourClassName alertWithPresenting:weakPresenting title:title text:text
                                   buttons:@[[L10n deleteButton], [L10n cancelButton]]
                                   handler:^(UIAlertAction *action, NSUInteger index)
        {
                if (action.style == UIAlertActionStyleDestructive) {
                        __typeof(weakSelf) strongSelf = weakSelf;
                        // Perform your actions using @strongSelf
                }
         }];
}

Yapok