--- title: "delegate not triggering is a mystery in ios" description: "delegate not triggering is a mystery in ios" author: "Anonymous User" published: 2014-10-13 updated: 2014-10-13 canonical: https://www.mindstick.com/forum/2368/delegate-not-triggering-is-a-mystery-in-ios category: "iphone" tags: ["iphone", "mobile development"] reading_time: 4 minutes --- # delegate not triggering is a mystery in ios I have developed this [class](https://www.mindstick.com/blog/165/generic-class-in-c-sharp) that is basically a UIAlertView with an input field that runs on blocks. So, whatever the user does on the alertView ([click](https://www.mindstick.com/articles/12423/social-login-magento-2-one-click-to-register-social) [cancel](https://answers.mindstick.com/qa/94501/how-can-i-cancel-my-singapore-flight-ticket), ok, or fill the text), returns to a [block](https://www.mindstick.com/forum/157599/explain-the-process-control-block-pcb-in-the-operating-system): **[HEADER](https://www.mindstick.com/articles/336036/explain-about-html-header-body-and-footer-tags)** ``` typedef void (^onClickBlock)(NSInteger buttonIndex, NSString *textoInput);  @interface AlertViewBlocoComInput : NSObject - (void)mostrarAlertViewBlocoComTitulo:(NSString *)titulo                              mensagem:(NSString *)mensagem                     tituloBotaoCancel:(NSString *)tituloCancel                     outrosBotoesArray:(NSArray *)titulosOutrosBotoes                   inputComPlaceHolder:(NSString *)textoPlaceholder                      comBlocoExecucao:(onClickBlock)bloco; @end ``` **\** **[IMPLEMENTATION](https://www.mindstick.com/forum/33764/how-to-implementation-of-class-in-c-sharp)****\** ``` @interface AlertComBloco : UIAlertView@property (nonatomic, copy) onClickBlock runOnClickBlock;@end  @implementation AlertComBloco@end  @interface AlertViewBlocoComInput () @end  @implementation AlertViewBlocoComInput   - (void)mostrarAlertViewBlocoComTitulo:(NSString *)titulo                              mensagem:(NSString *)mensagem                     tituloBotaoCancel:(NSString *)tituloCancel                     outrosBotoesArray:(NSArray *)titulosOutrosBotoes                   inputComPlaceHolder:(NSString *)textoPlaceholder                      comBlocoExecucao:(onClickBlock)bloco {   AlertComBloco *alerta = [[AlertComBloco alloc] initWithTitle:titulo                                                       message:mensagem                                                      delegate:self                                             cancelButtonTitle:tituloCancel                                             otherButtonTitles:nil];  alerta.runOnClickBlock =bloco;   // adicionar os outros botões  for (NSString *umOutroBotao in titulosOutrosBotoes) {    [alerta addButtonWithTitle:umOutroBotao];  }    [alerta setAlertViewStyle:UIAlertViewStylePlainTextInput];  UITextField *input = [alerta textFieldAtIndex:0];  input.placeholder = textoPlaceholder;   [alerta show]; }   - (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex{   AlertComBloco *alerta = (AlertComBloco *)alertView;  onClickBlock bloco = alerta.runOnClickBlock;   UITextField *input = [alertView textFieldAtIndex:0];   if (bloco) {    bloco(buttonIndex, input.text);  } }  @end ``` **\ \ \** **run it, it [shows](https://yourviews.mindstick.com/view/81380/new-york-violent-shooting-shows-people-are-not-safe-in-night-life) the alertView with the [message](https://www.mindstick.com/forum/12802/show-confirmation-message-yes-or-no-in-asp-dot-net), [placeholder](https://www.mindstick.com/forum/1519/how-do-i-remove-a-listbox-new-item-placeholder), perfect. I click cancel or fill the text and press ok and the alertview:clickedButtonAtIndex: is [never](https://yourviews.mindstick.com/view/290/zoos-prisons-for-beings-who-have-never-committed-a-crime) triggered. I am not seeing why.** ## Replies ### Reply by Anonymous User You can directly subclass UIAlertView and add your own initializer. I have abstracted your classes to a single subclass of UIAlertView and it works fine. Please see my posts below,\ ``` typedefvoid (^onClickBlock)(NSInteger buttonIndex, NSString *textoInput);         @interface AlertComBloco : UIAlertView        @property (nonatomic, copy) onClickBlock runOnClickBlock;        @end          @implementation AlertComBloco          - (id)initWithTitulo:(NSString *)titulo mensagem:(NSString*)mensagem tituloBotaoCancel:(NSString*)tituloCancel outrosBotoesArray:(NSArray *)titulosOutrosBotoes inputComPlaceHolder:(NSString *)textoPlaceholder            comBlocoExecucao:(onClickBlock)bloco{          if(self = [self initWithTitle:titulo message:mensagem delegate:self cancelButtonTitle:tituloCancel otherButtonTitles:nil, nil]){            _runOnClickBlock = bloco;            for (NSString *umOutroBotao in titulosOutrosBotoes) {              [self addButtonWithTitle:umOutroBotao];            }            [self setAlertViewStyle:UIAlertViewStylePlainTextInput];            UITextField *input = [self textFieldAtIndex:0];            input.placeholder = textoPlaceholder;           }          return self;        }           - (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex        {           UITextField *input = [alertView textFieldAtIndex:0];           if (self.runOnClickBlock) {            self.runOnClickBlock(buttonIndex, input.text);          }         }         @end ``` Then, you could call it with the block in your view controller just like this,\ ```   - (void)showAlert:(id)sender{  AlertComBloco *alertCombo = [[AlertComBloco alloc] initWithTitulo:@"Hi" mensagem:@"Custom Alert" tituloBotaoCancel:@"Cancel" outrosBotoesArray:@[@"Other"] inputComPlaceHolder:@"Placeholder" comBlocoExecucao:^(NSInteger buttonIndex, NSString *textoInput) {    NSLog(@"Button at index %ld, with text %@", (long)buttonIndex, textoInput);  }];  [alertCombo show];} ``` ### Reply by Anonymous User You haven't shown us how you're calling this but most likely your AlertViewBlocoComInput is a local variable that has fallen out of scope and is therefore deallocated before the user completes their input. You can demonstrate this by temporarily adding a dealloc method that will tell you when the object is deallocated. - (void)dealloc { NSLog(@"%s", __PRETTY_FUNCTION__); } In terms of fixing this, you could make your AlertViewBlocoComInput instance a class property, so it won't be released until you manually nil it. Or you can make AlertViewBlocoComInput maintain a strong reference to itself until clickedButtonAtIndex is called. Or, easiest, leverage the fact that UIAlertView already retains itself, so you can retire AlertComBloco altogether, folding it into AlertViewBlocoComInput: typedef void (^onClickBlock)(NSInteger buttonIndex, NSString *textoInput); @interface AlertViewBlocoComInput : UIAlertView - (instancetype)initComTitulo:(NSString *)titulo mensagem:(NSString *)mensagem tituloBotaoCancel:(NSString *)tituloCancel outrosBotoesArray:(NSArray *)titulosOutrosBotoes inputComPlaceHolder:(NSString *)textoPlaceholder comBlocoExecucao:(onClickBlock)bloco; @property (nonatomic, copy) onClickBlock runOnClickBlock; @end @implementation AlertViewBlocoComInput - (instancetype)initComTitulo:(NSString *)titulo mensagem:(NSString *)mensagem tituloBotaoCancel:(NSString *)tituloCancel outrosBotoesArray:(NSArray *)titulosOutrosBotoes inputComPlaceHolder:(NSString *)textoPlaceholder comBlocoExecucao:(onClickBlock)bloco { self = [super initWithTitle:titulo message:mensagem delegate:self cancelButtonTitle:tituloCancel otherButtonTitles:nil]; if (self) { self.runOnClickBlock =bloco; // adicionar os outros botões for (NSString *umOutroBotao in titulosOutrosBotoes) { [self addButtonWithTitle:umOutroBotao]; } [self setAlertViewStyle:UIAlertViewStylePlainTextInput]; UITextField *input = [self textFieldAtIndex:0]; input.placeholder = textoPlaceholder; } return self; } - (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex { if (self.runOnClickBlock) { UITextField *input = [alertView textFieldAtIndex:0]; self.runOnClickBlock(buttonIndex, input.text); } } @end And you'd call it like so:\ AlertViewBlocoComInput *obj = [[AlertViewBlocoComInput alloc] initComTitulo:@"title" mensagem:@"message" tituloBotaoCancel:@"OK" outrosBotoesArray:nil inputComPlaceHolder:@"Placeholder" comBlocoExecucao:^(NSInteger buttonIndex, NSString *textoInput) { // do whatever you want with `buttonIndex` and `textoInput` here // // NSLog(@"%ld %@", (long)buttonIndex, textoInput); }]; [obj show]; --- Original Source: https://www.mindstick.com/forum/2368/delegate-not-triggering-is-a-mystery-in-ios Copyright © MindStick Software Pvt. Ltd. This Markdown version is provided for developers, AI systems, and offline reading.