Custom UIAlertView with block callback - ios

Question

MyAlertView (subclass of UIAlertView) has this method:
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex {
if (self.clickedButtonAtIndexBlock != NULL)
self.clickedButtonAtIndexBlock(buttonIndex);
}
My question is how do I define the callback when I create the alert view? Obviously this is wrong:
alert.clickedButtonAtIndexBlock = ^{
NSLog(#"clicked: %d", buttonIndex);
}

Answer 1

I have written a blog post about how to (and why) add block callbacks to alert views, action sheets and animations:
http://blog.innovattic.com/uikitblocks/
If you just want a working implementation of this you can download the sources files from GitHub:
https://github.com/Innovattic/UIKit-Blocks
Usage:
UIAlertView* alert = [[UIAlertView alloc] initWithTitle:#"My easy alert"
message:#"Would you like to perform some kind of action?"
cancelButtonTitle:#"No"
otherButtonTitles:#"Yes", nil];
[alert setHandler:^(UIAlertView* alert, NSInteger buttonIndex) {
NSLog(#"Perform some kind of action");
} forButtonAtIndex:[alert firstOtherButtonIndex]];
[alert show];

Answer 2

Try doing something like this (I haven't tested it):
.h
typedef void (^MyClickedIndexBlock)(NSInteger index);
#interface YouInterface : YourSuperclass
#property (nonatomic, strong) MyClickedIndexBlock clickedIndexBlock;
#end
.m
//where you have to call the block
if (self.clickedIndexBlock != nil)
self.clickedIndexBlock(buttonIndex);
// where you want to receive the callback
alert.clickedIndexBlock = ^(NSInteger index){
NSLog(#"%d", index);
};

Answer 3

Check this OpinionzAlertView I have used it in few projects, works good for me. Here is sample:
OpinionzAlertView *alert = [[OpinionzAlertView alloc] initWithTitle:#"title"
message:#"message"
cancelButtonTitle:#"No, thanks"
otherButtonTitles:#[#"Done"]
usingBlockWhenTapButton:^(OpinionzAlertView *alertView, NSInteger buttonIndex) {
NSLog(#"buttonIndex: %li", (long)buttonIndex);
NSLog(#"buttonTitle: %#", [alertView buttonTitleAtIndex:buttonIndex]);
}];
[alert show];
I hope it will be helpful to you.

Answer 4

I have written a simple class LMSVBlocks to easily display alerts and get block callbacks in 1 line. Hopefully you will find it useful for this purpose
https://github.com/sourabhverma/LMSVBlocks
Concept: To make UIAlertView block compatible you need another class (Say LMSVBlockAlert) to handle the delegate method and when UIAlertView delegate will give a callback, LMSVBlockAlert class can send a call back in the block.
Code:
(LMSVBlockAlert.m)
Maintain all the instances of LMSVBlockAlert in an array so that they have a strong reference
static NSMutableArray *_LMSVblockHandlersArray = nil;
Keep the block handler in LMSVBlockAlert
#interface LMSVBlockAlert() <UIAlertViewDelegate>
#property (nonatomic, copy) void (^cancelCompletionBlock)();
#property (nonatomic, copy) void (^confirmCompletionBlock)();
#end
When a new alert is fired create new instance of LMSVBlockAlert which has a UIAlertView and delegate callbacks
+(LMSVBlockAlert*)newInstance{
LMSVBlockAlert *newIns = [[LMSVBlockAlert alloc] init];
[LMSVBlockAlert updateHandlerArrayWith:newIns];
return newIns;
}
When alert delegate is fired in LMSVBlockAlert send callback to block and clear this from memory
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex{
switch (buttonIndex) {
case 0://Cancel
{
if(_cancelCompletionBlock){
_cancelCompletionBlock();
}
}
break;
case 1://OK
{
if(_confirmCompletionBlock){
_confirmCompletionBlock(alertView);
}
}
break;
default:
break;
}
[_LMSVblockHandlersArray removeObject:self];
}
Now you can have two simple method which can give you UIAlertView callbacks
+(UIAlertView*)promptAlertTwoBtn:(NSString*)msg title:(NSString*)title onCancel:(void (^)())onCancel onConfirm:(void (^)())onConfirm{
return [[LMSVBlockAlert newInstance] showAlertMainWithTitle:title msg:msg onCancel:^{
onCancel();
} onConfirm:^(UIAlertView *alertView) {
onConfirm();
}];
}
-(UIAlertView*)showAlertMainWithTitle:(NSString*)title msg:(NSString*)msg onCancel:(void (^)())onCancel onConfirm:(void (^)(UIAlertView*))onConfirm{
UIAlertView *newAlert = nil;
newAlert = [[UIAlertView alloc]
initWithTitle:title
message:msg
delegate:self
#"Cancel"
otherButtonTitles:#"Confirm", nil];
[newAlert show];
self.cancelCompletionBlock = onCancel;
self.confirmCompletionBlock = onConfirm;
return newAlert;
}
Finally
Hope you found it useful..

Answer 5

You Can simple use these category classes from github.
Alert_ActionSheetWithBlocks
This provide Dismiss blocks for both AlertView and action sheets.
For Eg.
UIAlertView* alert = [[UIAlertView alloc] initWithTitle:#"AlertView+Block" message:#"WithBlocks" delegate:self cancelButtonTitle:#"Cancel" otherButtonTitles:#"newAlertViewWithTextFields",#"newAlertViewWithSingleTextField", nil];
[alert showWithFinishBlock:^(UIAlertView *alertView, NSInteger buttonIndex)
{ if (buttonIndex == 0) { } else if (buttonIndex == 1) { } }];
Apart from this it is also providing methods for text fields..
-(void) showWithFinishBlock:(FinishBlock_)block_; //-- AlertView with TextField [simple or secure]
-(void) showWithTextFieldBlock:(TextFieldBlock_)block_ secure:(BOOL)isSecure; //-- AlertView with two textfields username & password
You can take a look at example bundled with it.
I hope it will be helpfull to you.

Answer 6

Try out this
Say you created a class called MyCustomAlert, and you declare it as this variable.
MyCustomAlert *myCustomAlert = [[MyCustomAlent alloc] init];
You would put this in your header file.
- (void)setCompletion:(void (^)(int selectedButtonIndex))completion;
And you would put this in your implementation file
typedef void (^IntBlock)(int intBlock);
IntBlock _completion;
- (void)setCompletion:(void (^)(int selectedButtonIndex))completion{
_completion = completion;
}
now in the project where you declared "myCustomAlert". If you type in
[myCustomAlert setCompletion: // And select the autocomplete item
you will end up with this
[myCustomAlert setCompletion:<#^(int intBlock)completion#>]
the value <#^(int intBlock)completion#> will show up as a bubble like this.
when you press enter on the value, it will fill in the Block for you to use.
[myCustomAlert setCompletion:^(int selectedButtonIndex) {
}
when you want to trigger the _completion block in your custom class, you would call it somewhere in your code as follows.
- (void) callCompletionWithButtonIndex:(int) index{
if (_completion != nil) _completion(index);
}
hope that clears up the complication.

Answer 7

I have written a simple extension in Swift, hope it helpful
import UIKit
extension UIAlertView {
func show(completion: (alertView: UIAlertView, buttonIndex: Int) -> Void){
self.delegate = AlertViewDelegate(completion: completion)
self.show()
}
class func showInput(title: String?, message: String?, cancellable: Bool, completion: (text: String?) -> Void){
var strOK = NSLocalizedString("OK",comment: "OK")
var strCancel = NSLocalizedString("Cancel",comment: "Cancel")
var alert = UIAlertView(title: title, message: message, delegate: nil, cancelButtonTitle: cancellable ? strCancel : strOK)
alert.alertViewStyle = UIAlertViewStyle.PlainTextInput
if(cancellable) {
alert.addButtonWithTitle(strOK)
}
alert.show { (alertView, buttonIndex) -> Void in
if(cancellable && alertView.cancelButtonIndex == buttonIndex) {
completion(text: nil)
return
}
completion(text: alertView.textFieldAtIndex(0)?.text)
}
}
private class AlertViewDelegate : NSObject, UIAlertViewDelegate {
var completion : (alertView: UIAlertView, buttonIndex: Int) -> Void
var retainedSelf : NSObject?
init(completion: (UIAlertView, Int) -> Void ) {
self.completion = completion
super.init()
self.retainedSelf = self
}
func alertView(alertView: UIAlertView, didDismissWithButtonIndex buttonIndex: Int) {
var retain = self
retain.retainedSelf = nil
retain.completion(alertView: alertView, buttonIndex: buttonIndex)
}
}
}