I am a beginner in iOS development, and yesterday I learned about the UIAlertViewDelegate protocol from the Apple developer website.
I used -(void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex for managing the buttonindex and the performing the specific task.
However, when I use 2 UIAlertViews on the same outlet, they both use the same UIAlertViewDelegate protocol. How can I use different delegates for the other UIAlertView in my application?
Also, how can I change the default design of the UIAlertView in my Application?
Your UIAlertView has a property called tag. After you instantiate your alert view, set its tag:
myAlertView.tag = 1;
Use a different tag value for each of your alert views.
In your call back method, check the tag first to determine which alert view was dismissed and handle accordingly:
if (alertView.tag == 1) {
//alert view 1 was dimissed, handle that
} else if (alertView.tag == 2) {
//alert view 2 was dismissed
}
Related
In an iOS application that I am coding I am displaying a UIAlertView to ask the user for a password and I am trying to allow them to hit enter in the text field to submit the password.
I have handled the enter from the text field in a textFieldShouldReturn function. The problem is in the examples I have found online which say to use the dismissWithClickedButton method to handle the button click.
When I try this it simply dismisses the UIAlertView without checking the password. I really need the "OK" button I have setup to fire so I check the password.
Any ideas on how to do this?
You can use delegate method of UIAlertViewDelegate
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
Buttons in UIAlertView is stored in an array. So you can find the position of OK button
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{
if(buttonIndex == 1) //Your OK button
{
//Do Stuff
}
}
I have a few ViewController subclasses inside a UINavigation controller. I have successfully used UIAlertViews elsewhere in the application, and I know how to set the delegate and include the correct delegate methods, etc.
In a ViewController with a UITableView, I have implemented a 'pull to refresh' with a UIRefreshControl. I have a separate class to manage the downloading and parsing of some XML data, and in the event of a connection error, I post a notification. The view controller containing the table view observes this notification and runs a method where I build and display an alert:
UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:#"Connection Error" message:[[notification userInfo] objectForKey:#"error"] delegate:self cancelButtonTitle:#"Close" otherButtonTitles:nil];
alertView.alertViewStyle = UIAlertViewStyleDefault;
[alertView show];
The alert displays correctly, but the cancelButton is unresponsive - there is no way to dismiss the alert! Putting similar code (identical, but without the notification's userinfo) in the VC's viewDidLoad method creates an alert that behaves normally.
Is the refresh gesture hogging first responder or something? I have tried [alertView becomeFirstResponder]. I would be grateful for any advice…
Update: screenshot included… is this the right info? (can't embed this image for lack of reputation) http://i.stack.imgur.com/4CGqS.png
Edit
It seems like you have a deadlock or your thread is stuck waiting. You should look at your code and see what causes this.
Original answer which lead to update in OP
Make sure the alert is shown on the main thread:
dispatch_async(dispatch_get_main_queue(), ^{
//Open alert here
});
This isn't a solution per se, but I might try two quick things as you troubleshoot:
1) Hardcode some text in the UIAlert, rather than passing in the notification object. See if there is any change in behavior.
2) Try adding another button to the alert and an accompanying method to catch it. So you'll see if the delegate is getting ny buttons messages at all.
Try adding a tag to the alertView
alertView.tag = 0;
Then create the method alertView:clickedButtonAtIndex: in the view controller.
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{
if (alertView.tag == 0) {
[alertView dismissWithClickedButtonIndex:0 animated:YES];
}
}
I am using a UIAlertView to prompt users for a password. If the password is correct, I'd like the alert view to go away normally; if the password is incorrect, I'd like the alert view to remain (with the text changed to something like "Please try again."). How do I alter the default behaviour so that the view doesn't go away when a button is pressed?
I've tried the subclassing method suggested at Is it possible to NOT dismiss a UIAlertView, but the dismissWithClickedButtonIndex wasn't being called in my subclass. After reading the documentation I see that subclassing UIAlertView isn't supported, so I'd like to try another approach.
If this isn't possible with UIAlertView, is the best option to simply make a password view from scratch? Thanks for reading.
As this is very old question,but I got one solution and though of posting if any other developer need in near future.
Implement protocol methods in .h file
In order to respond to button taps in our UIAlertView, we will use the – alertView:clickedButtonAtIndex: protocol method as
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{
}
//Now below code will check if uitextfield value.
- (BOOL)alertViewShouldEnableFirstOtherButton:(UIAlertView *)alertView
{
NSString *inputText = [[alertView textFieldAtIndex:0] text];
if( [inputText length] > 0)
{
//text field value is greater than zero ,then Done button will appear as blue,or else it will be blurred
return YES;
}
else
{
return NO;
}
}
You could design a UIView similar to the alertview and can cal the functions inside this. Removing a UIView is controlled by you.
It's not possible to leave the alert there when a button has been clicked.
You can either disable the "OK" button by delegate method alertViewShouldEnableFirstOtherButton:, if you are checking the password locally, or just show another alert later. The second alert can contain a different information, e.g. "Password incorrect" instead of "Enter password".
I've got an issue where an object that's creating a UIAlertView is sending a message back to its delegate, but the delegate object is crashing.
I've got it working OK in a couple of other instances, but what I'm trying to do in this case (and what's different from other similar questions) is that the object that instantiates the alert, and which acts as its delegate is not itself a view, but rather an object that is instantiated within a view. To wit, in the parent view:
#implementation
*MyCustomObject customObject;
-(void)viewDidLoad {
customObject = [[MyCustomObject alloc] init];
}
#end
And in the custom object:
-(void)DoCoolThings {
UIAlertView *message = [[UIAlertView alloc] initWithTitle:#"Do You Want To Do Cool Things"
message:#"...description of cool things..."
delegate:self
cancelButtonTitle:#"No Thanks"
otherButtonTitles:#"HELLS YES", nil];
[message show];
}
and
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{
if (buttonIndex == 1) {
[self DoCoolThings];
} else {
[self GoAndCry];
}
}
When I do the alert view within a viewcontroller object, everything is fine. Doing it within this sub-object which itself has no view allows me to create the alert, but that object--which shouldn't be getting de-allocated based on the scoping--doesn't seem to want to continue to act as a delegate.
The error I'm getting is indeed a de-allocation message, but I feel strongly that this is not the problem because if I remove the alert, all the other stuff--specifically, it's a wrapper for a storekit purchase process--works fine, and all those delegate methods work happily.
I've got a solution which will allow me to move the Alert into the parent view's methods, but I was hoping not to have to. Is this limitation real, or is it my imagination? IE am I doing something else wrong?
I want to make a "terms and conditions" screen that pops up the very first time that app is opened. On this view I would add a button that says "agree," and upon clicking it the code would execute:
[self dismissViewControllerAnimated:YES completion:nil];
...and would go to the first view of the app.
I am currently using a Tab Bar Controller that has 4 ViewControllers. So basically, I just need to have some method in viewWillAppear on my first ViewController that checks for an NSUserDefault key:value. The first time the app opens, it will be zero. After they click agree, I'll set it to 1 and the bit of code would never execute again.
Can you please offer some code to accomplish the task of routing the view from the firstViewController's view to this alternate view controller upon loading the app?
Thanks!
In the viewWillAppear method in your FirstViewController, check NSUserDefaults then present your TermsViewController. After user click agree in TermsViewController, set NSUserDefaults then call
[self.presentingViewController dismissModalViewControllerAnimated:YES]
The use of the popover window can get complicated. Try something like the following if you have little experience with Objective-C.
- (void)viewDidLoad {
if ([termsvalue == 0]) {
NSString *msg = [NSString stringWithFormat:#"Do you agree with the terms of use?"];
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"- Confirmation -"
message:msg
delegate:self
cancelButtonTitle:#"Disagree"
otherButtonTitles:#"I agree", nil];
[alert setTag:100];
[alert show];
}
}
- (BOOL)alertViewShouldEnableFirstOtherButton:(UIAlertView *)alertView { // Validation
if ([alertView tag] == 100) {
return YES;
}
}
- (void)alertView:(UIAlertView *)alertView didDismissWithButtonIndex:(NSInteger)buttonIndex { // Go
if ([alertView tag] == 100) {
if (buttonIndex == 1) {
// The user has agreed
}
}
}