How to use UIAlertController to replace UIActionSheet? - ios

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?

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.

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];
}]];

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)

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)

Answer 5

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

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
}
}];
}