I'm doing a contacts app, so in one page, I need it to don't open if there's no contact, so I set a if in viewWillAppear. Everything works ALMOST great: when I select this tab, an alert tells me that there's no contact added and the tab changes, but the View doesn't
![enter image description here][1]
https://cloudup.com/cZDl8XW1aun (screenshot link)
I done a test and if I put the changing tabBar code in other place except ViewDidLoad or ViewWillAppear it works, but I don't want this.
Sorry for my bad english or if I done an idiot mistake, I'm a noob.
if (contacts.count == 0)
{
UIAlertView *alerta = [[UIAlertView alloc] initWithTitle:#"Attentione" message:#"You doesn't have any contacts added" delegate:nil cancelButtonTitle:#"OK" otherButtonTitles:nil];
[alerta show];
self.tabBarController.selectedIndex = 1;
}
else
{
...
.
..
..
.
}
Be sure to call the code to set the selected index from the viewDidLoad method:
- (void)viewDidload
{
[super viewDidLoad];
// Call from viewDidload
[self.tabBarController setSelectedIndex:1];
}
Related
Let's say that when the user presses a button a message needs to be shown and then a modal view controller is displayed.
I would write something like that :
- (void)pickImageButtonPressed:(id)button {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Alert"
message:#"Some alert"
delegate:nil
cancelButtonTitle:#"OK"
otherButtonTitles:nil];
[alert show];
[alert release];
UIImagePickerController *picker = [[UIImagePickerController alloc] init];
picker.delegate = self;
picker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
[[UIApplication sharedApplication].keyWindow.rootViewController
presentModalViewController:picker animated:YES];
[picker release];
}
With this code, the modal view controller is simply not displayed !
However, if I switch the two blocks of code (show modal first, then show the alert), the view controller is displayed modally and the alert shows up above it, exactly as I want.
My question is: why the alert prevents the modal view controller from being displayed ?
Please note that I do not want to wait for alert to be dismissed before calling presentModalViewController.
Update :
I figured out that my production code was a bit more complicated than what I first put. I updated the example code and then finally found a simple example to reproduce the problem.
Note that in my production code, the popup is displayed from a place where I don't have any reference to a view controller, that's why I use [UIApplication sharedApplication].keyWindow.rootViewController instead of a direct reference to a view controller
I finally found the answer. The issue really was on this line:
[[UIApplication sharedApplication].keyWindow.rootViewController
presentModalViewController:picker animated:YES];
When an alert is displayed, [UIApplication sharedApplication].keyWindow.rootViewController is nil !. That's why the picker was never displayed. And that's why it worked when I switched the two blocks.
Now I need to find a way to get the most relevant view controller to present the picker modally...
I am working with a master detail application. In the master section records are listed, and detail section shows each record details. The detail section is a table view where we can edit each record. the problem is that "while editing a record,if i tap a record on the other side, any changes that i have made on the original record are lost and new record details are shown in the table view"...
can anyone please tell me how to show an alert that asks for "save or cancel" , before "showing the new record details"..
any changes that i have made on the original record are lost
A common rule in developing applications is
NEVER loose the user's work
So it would maybe just be the best idea to just save what the user changed.
But let's head to your actual question:
can anyone please tell me how to show an alert
I think you mean those alters looking like push notifications with two buttons.
You create them with UIAlertView.
Then in the alert's delegate you can figure out which button was pressed and you can decide how to go on. Just check out the documentation for UIAlertView - it's pretty simple :)
try this,
-(void)tableView:(UITableView *)tableView1 didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:LString(#"ISCO_FLOW_CALC") message:LString(#"DELETE_MESSAGE") delegate:self cancelButtonTitle:LString(#"CANCEL") otherButtonTitles:LString(#"SAVE"), nil];
alert.tag=11;
[alert show];
[alert release];
}
- (void)alertView:(UIAlertView *)alertView didDismissWithButtonIndex:(NSInteger)buttonIndex {
if(buttonIndex==1 && alertView.tag==11)
{
//your save data action;
}
if(buttonIndex==0 && alertView.tag==11)
{
//your Cancel data action;
}
}
Keep a reference to your DetailViewController in the MasterViewController
eg. in your MasterViewController.h:
DetailViewController *detailVC;
Set this reference to your most recent DetailViewController in didSelectRowAtIndexPath and always check if it is not nil before showing a new detailVC
DetailViewController *controller=[[DetailViewController alloc] init]; //Or similar
if (detail){
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Save or Cancel" message:#"Save or Cancel" delegate:self cancelButtonTitle:#"Cancel" otherButtonTitles:#"Save",nil];
[alert show];
}
else{
detailVC=controller;
//Show controller
}
Now show the new detailViewController after the user tapped a button of the UIAlertView:
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex {
if (buttonIndex==0) { //Tapped cancel
//show detailVC
}
else{ //Tapped save
//save
//Show detailVC
}
}
Hope this helps
I have code setting up a UIAlertView:
-(IBAction)showMessage
{
//NSInteger *buttonIndex = NULL;
UIAlertView *message = [[UIAlertView alloc] initWithTitle:nil
message:nil
delegate:nil
cancelButtonTitle:#"Cancel"
otherButtonTitles:#"Email",#"SMS",#"Facebook",#"Twitter", nil];
[message show];
}
and code explaining what to do once the user makes a choice:
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{
if (buttonIndex == 1){
[self openMail];
}
else if (buttonIndex == 2)
//etc.
}
But what I can't figure out is how to connect the two. The obvious answer is to add a line to the first piece of code calling alertView: clickedButtonAtIndex on UIAlertView *message, but how do you assign buttonIndex? How do you tell alertView whether the user has chosen Facebook, Email, etc?
Add to the header file if you haven't already:
#interface YourClass : UIViewController <UIAlertViewDelegate>
{
}
...etc
and in your AlertView code change delegate:nil to delegate:self
For more information have a look at the Apple Docs:
http://developer.apple.com/library/ios/#DOCUMENTATION/UIKit/Reference/UIAlertViewDelegate_Protocol/UIAlertViewDelegate/UIAlertViewDelegate.html
From the docs:
The button indices start at 0. If this is the cancel button index, the alert view is canceling. If -1, the cancel button index is not set.
(1) You want to set delegate:self when you initialize the message. Also, in your interface declaration, do something like:
#interface myClass: UIViewController <UIAlertViewDelegate>
This way, your handler function automatically gets called when the user makes a selection.
(2) Buttons are indexed in the order you listed them.
(3) Since you have a lot of options for the user to choose from, it is better to use UIActionSheet instead of UIAlertView. Alerts are generally used for simple Yes/No-type selections.
Hope this helps!
I am displaying aNavController as a modalViewController in a specific frame CGRectMake(40,50, 400, 500). Which is working fine. Now I have a button in self (viewcontroller on which modalViewController is presented), on pressing that button I need to display some message on aNavController. But problem is when I am presenting a modalViewController. Whole screen area got dimmed/disabled. So, not able to touch/click that button in self.
Here is my code to present a view controller. I thought, I am missing something here. Please Help. Thanks in advance.
aNavController.modalPresentationStyle = UIModalPresentationFormSheet;
anavController.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
[self presentModalViewController:aNavController animated:YES];
aNavController.view.superview.frame = CGRectMake(40,50, 400, 500);
presentModalViewController create a modal dialog. When modal view controller is up, users can't do any thing on parent view until the the modal view is dismissed.
The problem is you're instantiating a UIAlertView at the same time as the presentModalViewController call your modal view in UIAlertView's delegate method clickedButtonAtIndex.
Like so:
- (IBAction)clickedMyButton:(id)sender
{
UIAlertView *alertView = [[UIAlertView alloc]
initWithTitle: #"Title"
message: #"Message"
delegate:self
cancelButtonTitle:#"Close Button"
otherButtonTitles:#"Modal Button", #"Some Other Button", nil];
[alertView show];
}
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex {
if (buttonIndex == 0) {
NSLog(#"User Selected Cancel");
}
else if (buttonIndex == 1) {
NSLog(#"Modal Button Clicked");
aNavController.modalPresentationStyle = UIModalPresentationFormSheet;
anavController.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
[self presentModalViewController:aNavController animated:YES];
aNavController.view.superview.frame = CGRectMake(40,50, 400, 500);
}else {
NSLog(#"Some Other Button Clicked");
}
}
Or, if you wish for your UIAlertView to show on top of your navigation controller, ignore the above and simply wait to call your alert until the navigation controllers - (void)viewDidAppear:(BOOL)animated method.
In addition, I recommend you change your frame to stay within the bounds of the screen unless absolutely necessary. ex: CGRectMake(40, 50, 320, 480);
Finally, I am able to do workaround the things which work same way as a UIModalPresentationFormSheet.
I added the aNavController as a subview to the [[UIApplication sharedApplication] keyWindow] and which solves my all the problems.
Thank you all for your comments.
Having a simple Navigation Controller in place (starting the Navigation Based Application project) I created a new View with a XIB file.
on my HomeViewController (Home screen with all options as UIButton's I have:
#implementation HomeViewController
-(IBAction) optionChoosed:(UIButton *)button
{
NSString *msg = [NSString stringWithFormat:#"Button: %d", button.tag];
UIAlertView *alert=[[UIAlertView alloc] initWithTitle:#"Hi" message:msg delegate:nil cancelButtonTitle:#"Go away" otherButtonTitles:nil];
switch (button.tag) {
case 13:
// Simple Search
[self loadSimpleSearch]; break;
default:
[alert show];
break;
}
[alert release];
}
-(void)loadSimpleSearch
{
SimpleSearchViewController *controller =
[[SimpleSearchViewController alloc] initWithNibName:#"SimpleSearchViewController" bundle:nil];
[self.navigationController pushViewController:controller animated:YES];
[controller release];
}
witch works great!
it Pushes the View into the front of the stack!
Now, because in my 2nd view SimpleSearchViewController I have self.title = #"myTitle"; I get the Title in the NavigationBar as well the back button (as I have the same setting on the HomeViewController)
I thought that the NavigationViewController would handle the pop of the current view, but it does not.
What do I have to do, to pop the SimpleSearchViewController?
Where do I use [self.navigationController popViewControllerAnimated:YES];
as the view continues there, and ViewDidUnload is never called.
My idea was that this should be handle in the first ViewController, the HomeViewController but I have no idea what is the method I should hook to, and I read the documentation and I can't figure it out :-/
Any help is greatly appreciated, thank you.
HomeViewController
alt text http://cl.ly/XNS/Screen_shot_2010-04-21_at_22.38.51.png
SimpleSearchViewController
alt text http://cl.ly/YDw/Screen_shot_2010-04-21_at_22.40.00.png
SimpleSearchViewController after pressing the Back button
alt text http://cl.ly/XLO/Screen_shot_2010-04-21_at_22.40.21.png
To add the image from a comment that asks if HomeViewController as the root controller for the NavigationViewController
Not sure if this helps but when implementing navigationItem in code, if you don't call the super the popping functionality will not be present
-(UINavigationItem*) navigationItem
{
UINavigationItem* item = [super navigationItem];
item.title = #"search";
return item;
}