In my application i want alertview in many views.So what i did is just wrote a single alertview in a utility class and use it everywhere.This is working fine.
I even tried by setting <UIAlertViewDelegate> but in vain.
Utility Class
#interface SSUtility: NSObject<UIAlertViewDelegate> {
}
+(void)showAllert;
#end
#implementation SSUtility
+(void)showAllert{
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:NSLocalizedString(#"gotoappAppstore",#"") message:#"" delegate:self cancelButtonTitle:NSLocalizedString(#"Ok",#"") otherButtonTitles:nil];
[alert show];
[alert release];
}
#end
Now from my view
-(void)pressButton{
[SSutility showAllert]
}
Now i want to give a button action for alert view click and call a method on that button action.
So im stuck with,in which class i want to implement this method.I tried it in utility class and viewc controller but the method is not getting triggered when "ok" button is pressed.
-(void)alertView:(UIAlertView *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex
Can anyone please help me on this?
Thanks in advance.
You wire the alert view button response method by setting your alert view object delegate usually to the owner object and implementing the – alertView:clickedButtonAtIndex: method.
You need 4 parts in your code:
instantiate your UIAlertView object
send show message to your UIAlertView object
set delegate
implement the delegate method
Example:
UIAlertView *myAlertView = [[UIAlertView alloc] initWithTitle:#"myTitle" message:#"myMessage" delegate:self cancelButtonTitle:#"Cancel" otherButtonTitle:#"Another button"];
[myAlertView setDelegate:self];
[myAlertView show];
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{
if (buttonIndex == 0) //index 0 is cancel, I believe
{
// code for handling cancel tap in your alert view
}
else if (buttonIndex == 1)
{
// code for handling button with index 1
}
}
I would recommend you get more familiar with how delegates work. This'll come back again a lot.
You set delegate:nil in your UIAlertView's init.
You should set to delegate:self, like this:
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:NSLocalizedString(#"gotoappAppstore",#"") message:#"" delegate:self cancelButtonTitle:NSLocalizedString(#"Ok",#"") otherButtonTitles:nil];
in order to use the delegate in the same class (a.k.a. self).
As a sidenote, if you use Automatic Reference Counting (ARC), you do not need [alert release] (your Xcode compiler should warn you about this)
Related
Am new to AlertViews with actions. Have set mine up as in the examples I found here including setting the delegate method in my .h, but when I debug find that it is not reaching my clickedButtonAtIndex method. Probably missing something simple :-/ Any help solving this would be appreciated, thanks.
Here's my code:
.h file
#interface LineDetailViewController : UIViewController <UIAlertViewDelegate>
. m file:
- (IBAction)removeLineButton:(UIButton *)sender {
NSString * requestSubmitText = [NSString stringWithFormat:#"Hey Bro are you sure you want to remove this line you created, it will also remove all the reviews attached and can not be undone?"];
UIAlertView *removeLineRequest = [[UIAlertView alloc] initWithTitle:#"WARNING!!"
message:requestSubmitText
delegate:nil
cancelButtonTitle:#"Remove It"
otherButtonTitles:#"Cancel",nil];
[removeLineRequest show];
- (void)alertView:(UIAlertView *)alertView
clickedButtonAtIndex:(NSInteger)buttonIndex{
//if (buttonIndex == [alertView cancelButtonIndex]){
if (buttonIndex == 0){
NSLog(#"Cancel button pressed");
}else{
NSLog(#"other button pressed");
}
}
You have to set delegate to self
UIAlertView *removeLineRequest = [[UIAlertView alloc] initWithTitle:#"WARNING!!"
message:requestSubmitText
delegate:self // <- here
cancelButtonTitle:#"Remove It"
otherButtonTitles:#"Cancel",nil];
Call removeLineRequest.delegate = self.
While creating your alert view set your delegate to self . And you have already implemented the UIAlertViewDelegate.
To solve your problem, just set the delegate to self instead of nil.
Some additional info,
UIAlertView and UIAlertViewDelegate have been deprecated. As per the documentation,
UIAlertView is deprecated. Use UIAlertController with a preferredStyle of UIAlertControllerStyleAlert instead.
Relevant tutorial here
I try to have the delegate method called but it isn't. What should I change in my code? Thank you.
I tried to add in Class1.m:
+(void)popupAlert:(NSString*)msg tag:(NSInteger)tag{
Class1 *c= [[Class1 alloc]init];
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#""
message:msg
delegate:c (I also tried c.self)
cancelButtonTitle:...
otherButtonTitles:...,nil];
alert.tag=tag;
[alert show];
}
I try to set alertview delegate to make this delegate method called.
-(void)alertView:(UIAlertView *)alertView didDismissWithButtonIndex:(NSInteger)buttonIndex
Here is what I'm doing:
Class1.h:
+(void)popupAlert:(NSString*)msg tag:(NSInteger)tag;
Class1.m:
+(void)popupAlert:(NSString*)msg tag:(NSInteger)tag{
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#""
message:msg
delegate:self
cancelButtonTitle:...
otherButtonTitles:...,nil];
alert.tag=tag;
[alert show];
}
-(void)alertView:(UIAlertView *)alertView didDismissWithButtonIndex:(NSInteger)buttonIndex{
//some coding
}
Class2.m:
-(void)func1{
[Class1 popupAlert:#"blah blah" tag:0];
}
It seems c gets dealloced right after [alert show]; because there are no strong reference pointing to this object afterwards and the delegate becomes nil;
In other example you should turn instance method
-(void)alertView:(UIAlertView *)alertView didDismissWithButtonIndex:(NSInteger)buttonIndex
to class method:
+(void)alertView:(UIAlertView *)alertView didDismissWithButtonIndex:(NSInteger)buttonIndex
Rethink your architecture.
You are creating the alert in a class method. (That is indicated by the leading + instead of -). Within that self is a reference to the class, not the object.
alertView:didDismissWithButtonIndex: is an instance method. I am not even sure that you could apply a delegate protocol to the class instead of the instances. But if you can, then your delegate method would have to be a class method too.
+(void)alertView:(UIAlertView *)alertView didDismissWithButtonIndex:(NSInteger)buttonIndex
Well, I am just thinking of that and DO NOT PROMISE that it works that way.
If I were you I'd go for a singleton pattern and use instance methods to throw the alert and to respond to the delegate protocol.
Anyway, I am wondering which warning xcode displays on delegate:self and why you are not telling us about the warning. Warnings are there for a reason.
Alertview delegate property is week reference.
So once you finished the +(void)popupAlert:(NSString*)msg tag:(NSInteger)tag method then all local variables on Stack will removed from memory.
means destroyed. So even you set the delegate there it wont work.
#property(nonatomic,assign) id /*<UIAlertViewDelegate>*/ delegate;
So you should do like this
-(void)func1{
Class1 *class1 = [[Class1 alloc] init];
[Class1 popupAlert:#"blah blah" tag:0 withDelegate:class1];
}
+(void)popupAlert:(NSString*)msg tag:(NSInteger)tag withDelegate:(id)delegateOfAlert]{
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#""
message:msg
delegate:delegateOfAlert
cancelButtonTitle:...
otherButtonTitles:...,nil];
alert.tag=tag;
[alert show];
}
I am creating a drawing application where the user can draw using their finger strokes. I am trying to make a button that asks the user if they would like to clear the canvas. This alert has two buttons "Yes" and "No". I have the alert view appearing correctly but I have spent all day trying to figure out how to hook the buttons up to actions. I have so far had no success even after reading and watching from many instructional sources. From everything that I have read I can't understand why it would not be working. I have included UIAlertViewDelegate in my .h file also.
Here is my alert view:
- (IBAction)clearButton:(id)sender {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Clear Canvas"
message:#"Are you sure?"
delegate:nil
cancelButtonTitle:#"No"
otherButtonTitles:#"Yes", nil];
[alert show];
}
Here is my clear canvas method:
- (void)clearCanvas:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex {
if (buttonIndex == 1)
drawImage.image = nil;
}
Any help or pointers would be greatly appreciated! I'm self taught and still very much a beginner!
Thanks!
- (IBAction)clearButton:(id)sender {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Clear Canvas"
message:#"Are you sure?"
delegate:self
cancelButtonTitle:#"No"
otherButtonTitles:#"Yes", nil];
[alert show];
}
Notice the difference in the delegate parameter. You must conform to the delegate you have declared in the .h
Secondly, use the delegate method -alertView:clickedButtonAtIndex
I'd like to selectively enable the 'save' button on my UIAlertView so that you can't save a file with no name. I can listen to text changed events for the attached UITextView (the style is UIAlertViewStylePlainText), but I can't see how to access the buttons so that I can do the enable/disable. I've tried iterating through [alertView subviews], but there is only the label in there (no buttons). Where do I need to look to directly access the UIButtons attached to a UIAlertView?
Simple, just implement the UIAlertViewDelegate in your class and utilize the alertViewShouldEnableFirstOtherButton: delegate method. You can use this to check the length of the text field, and enable the button accordingly...
- (BOOL)alertViewShouldEnableFirstOtherButton:(UIAlertView *)alertView
{
return [[[alertView textFieldAtIndex:0] text] length] > 0;
}
Make sure you set your view controller to conform to this delegate in your interface using < UIAlertViewDelegate > and to set this class as the alerts delegate upon instantiation.
Instantiate your alertview:
UIAlertView *av = [UIAlertView alloc] initWithTitle:#"my title" message:#"message" delegate:self cancelButtonTitle:#"Cancel" otherButtonTitles:#"Save", nil];
});
Then make sure your class implements UIAlertViewDelegate, and look for the button index of the button you want to listen to:
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex{
if (buttonIndex==1) {
//save here
}
}
0x7fffffff posted right answer, but if someone is looking for answer how to add that textfield and save button to UIAlertView, here is the answer:
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Save" message:#"" delegate:self cancelButtonTitle:#"Cancel" otherButtonTitles:#"Save", nil];
[alert setAlertViewStyle:UIAlertViewStylePlainTextInput];
This delegate method:
- (BOOL)alertViewShouldEnableFirstOtherButton:(UIAlertView *)alertView {
return [[[alertView textFieldAtIndex:0] text] length] > 0;
}
won't work if you add that save button with addButtonWithTitle: method.
And when save button is clicked, this delegate method is called and here you can read what user wrote to that text field:
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex {
if(buttonIndex == 1) {
// Save button clicked
NSLog(#"%#", [[alertView textFieldAtIndex:0] text]);
}
}
You can't access the buttons of an alert view as of iOS 7. Unfortunately they made the subviews completely hidden and there's no way to access them.
I've created a UIAlertView and now I want to check which button the user presses.
My code is:
- (IBAction)button1 {
{
UIAlertView *alert1 = [[UIAlertView alloc] init];
[alert1 setTitle:#"Hello"];
[alert1 setMessage:#"Do you like smoking?"];
[alert1 addButtonWithTitle:#"Yes"];
[alert1 addButtonWithTitle:#"No"];
[alert1 show];
}
}
How can I check it with if-else statement?
You must set the delegate of your UIAlertView to the class that will handle the callbacks from the UIAlertView itself
E.g.
[alert1 setDelegate:self];
Where self is your current UIViewController that implements the protocol <UIAlertViewDelegate>.
When the user taps a button, the UIAlertView will call back to whatever object you set as the delegate, in my example we are using the UIViewController that created the UIAlertView. Once we get the callback, we can check which button index has been tapped and act accordingly. This is a basic delegation pattern that is used throughout iOS development, especially UIKit.
Example
#interface MyViewController : UIViewController() <UIAlertViewDelegate>
#end
#implementation MyViewController
- (IBAction)button1 {
{
UIAlertView *alert1 = [[UIAlertView alloc] init];
[alert1 setTitle:#"Hello"];
[alert1 setMessage:#"Do you like smoking?"];
[alert1 addButtonWithTitle:#"Yes"];
[alert1 addButtonWithTitle:#"No"];
[alert1 setDelegate:self];
[alert1 show];
}
}
#pragma mark - UIAlertViewDelegate
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{
// Handle interaction
switch (buttonIndex)
{
case 0:
NSLog(#"Yes was pressed");
break;
case 1:
NSLog(#"No was pressed");
break;
}
}
#end
It is very important you specify in the header file, or class interface extension that your class implements the <UIAlertViewDelegate>.
I recommend you see the UIAlertViewDelegate Protocol Reference for more information, and you can follow this approach for many other UIKit components.
Implement UIAlertViewDelegate protocol in your view controller, set it as a delegate to the UIAlertView, and wait for the alertView:clickedButtonAtIndex: event, like this:
#interface MyViewController : UIViewController <UIAlertViewDelegate>
-(void)alertView:(UIAlertView *)alertView
clickedButtonAtIndex:(NSInteger)buttonIndex;
#end
#implementation MyViewController
-(void)alertView:(UIAlertView *)alertView
clickedButtonAtIndex:(NSInteger)buttonIndex {
NSLog(#"Button %d clicked...", (int)buttonIndex);
}
#end
Change the code that displays the alert view as follows:
UIAlertView *alert1 = [[UIAlertView alloc] init];
[alert1 setTitle:#"Hello"];
[alert1 setMessage:#"Do you like smoking?"];
[alert1 addButtonWithTitle:#"Yes"];
[alert1 addButtonWithTitle:#"No"];
alert1.delegate = self; // <<== Add this line
[alert1 show];
Adding on to the answer by Jeff, I think that you have to enable the other button in order to place your logic when the button is clicked.
In order to creating the button with your code:
- (IBAction)button1
{
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Hello"
message:#"Do you like smoking?"
delegate:self
cancelButtonTitle:#"Yes"
otherButtonTitles:#"No", nil];
[alert show];
}
But before knowing which button is clicked, you have to enable the first other button, by calling this delegate method:
- (BOOL)alertViewShouldEnableFirstOtherButton:(UIAlertView *)alertView
{
return YES;
}
This will enable the NO button that you have created. Then, you will be able to do some logic with the clickedButtonAtIndex method, which I suppose you will be doing.
Implement the UIAlertView delegate method:
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{
if (buttonIndex == 0) {
// i love smoking!
} else if (buttonIndex == 1) {
// i hate smoking!
}
}
Be sure to declare the UIAlertViewDelegate in your header class.
Make sure that the alertViewShouldEnableFirstOtherButton: method returns YES, if not you will not be able to put in your logic for when the button is pressed.
Hope this helps! :)
The best thing you can do is make the class that presents your alert view conform to the UIAlertViewDelegate protocol and implement the method –alertView:clickedButtonAtIndex:. That way you'll know what button was clicked.
Hope this helps!