ivar for view controller in appdelegate.m - ios

Question

edit 1
I am adding some code to indicate its state after I have tried to work with codeInOrange's answer so far which so far behaves like my code originally behaved, that is sample link shows up at first in the text field and can be altered by the user, but when the user returns to the VC, any new link text has been replaced by the original sample link. My reason for posting this additional code is to try to reconnect with codeInOrange's promising answer because I am misunderstanding the logical flow of his original suggestions and his later comments.
In the current Storyboard I am leaving the Text field and the Placeholder Text empty because the sample link seems to be adequately supplied by the viewDidLoad method below.
- (void)viewDidLoad
{
[super viewDidLoad];
self.urlNameInput.text = #"sample http";
// Do any additional setup after loading the view, typically from a nib.
self.urlNameInput.clearButtonMode = UITextFieldViewModeAlways;
self.urlNameInput.clearsOnBeginEditing = NO;
}
- (BOOL)textFieldShouldReturn:(UITextField *)textField {
if (textField == self.urlNameInput) {
[textField resignFirstResponder];
[self processPbn];
}
return YES;
}
- (void)viewDidAppear:(BOOL)animated
{
AppDelegate *appDelegate = [UIApplication sharedApplication].delegate;
// self.urlNameInput.text = appDelegate.stringForTextField;
appDelegate.stringForTextField = self.urlNameInput.text;
}
- (void) processPbn
{
NSURLRequest *theRequest = [NSURLRequest requestWithURL:[NSURL URLWithString:self.urlNameInput.text] cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:60.0];
[NSURLConnection sendAsynchronousRequest:theRequest queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *connection, NSData *data, NSError *error)
{
// lots of detail code has been elided in this method
self.iboard = 0;
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:toMatch options:NSRegularExpressionDotMatchesLineSeparators error:&error];
for (NSTextCheckingResult* board in [regex matchesInString:string options:NSRegularExpressionDotMatchesLineSeparators range:NSMakeRange(0, [string length])])
{
if (self.iboard>0) {
AppDelegate *appDelegate = [UIApplication sharedApplication].delegate;
appDelegate.stringForTextField = self.urlNameInput.text;
}
}];
}
edit 1
edit 0
I do not want to preserve the text between application shutdowns and launches, so the answer using NSUserDefaults is not quite what I need.
Also, it appears from my trials that the solution suggested by Michael Dautermann which suggests either putting my intialization text in viewDidLoad or in the Xib or Storyboard, does not work because the text always returns to its initial value upon return to the VC (likely because the viewDidLoad method is triggered), so I think I do need to create an ivar in my AppDelegate.m as I asked in my original question, and not in my ViewController.m viewDidLoad, to get the desired result, apparently. Perhaps it would be easier to create a B00L ivar in AppDelegate.m which is a flag that tells whether original text or current text is desired. But I cannot figure out how to do that, either. So, please consider this edit in your answer.
edit 0
My AppDelegate.m contains the following code.
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
UIStoryboard *sb = [UIStoryboard storyboardWithName:#"MainStoryboard" bundle:nil];
BDViewController *vc = [sb instantiateInitialViewController];
self.viewController = (id)vc;
}
self.window.rootViewController = self.viewController;
[self.window makeKeyAndVisible];
return YES;
}
In the VC I want an ivar, an NSString, to be set at launch so that it can be the example text in my UITextField. Later I want that UITextField to be adjusted to an new value when the user supplies valid text into a UITextField.
Currently in my VC.h, the text field is declared and is synthesized in VC.m as follows .
#property (nonatomic, strong) UITextField *urlNameInput;
#synthesize urlNameInput;
I have tried putting the following code into didFinishLaunchingWithOptions: but do not see the desired text when I run the app.
self.viewController.urlNameInput.text = #"example http";
How can I programmatically accomplish my goal of initializing the UITextField?

Answer 1

Put that "urlNameInput.text =" bit into your view controller's "viewDidLoad" method, instead of the "didFinishLaunchingWithOptions:" method (where your view controller is not likely yet instantiated.
Even better than that, just set the initial text in your storyboard or XIB file and then you can programmatically adjust it later on.

Answer 2

Ok I'm having a hard time understanding what you're trying to do but creating an NSString iVar on your app delegate (although there are many other solutions) will allow you to set the textfield text to whatever you want when that VC comes back on the screen.
In your AppDelegate.h
#property (strong, nonatomic) NSString *stringForTextField;
This way you can initialize your textfield text when the view is loaded (viewDidLoad)
self.urlNameInput.text = #"example http";
then whenever that text value needs to be changed (say for example in textFieldShouldReturn in the other view controller. I'm assuming you have another textfield based on your question)
AppDelegate *appDelegate = [UIApplication sharedApplication].delegate;
appDelegate.stringForTextField = textField.text;
and in viewDidAppear in the VC with the textField set that value.
AppDelegate *appDelegate = [UIApplication sharedApplication].delegate;
self.urlNameInput.text = appDelegate.stringForTextField;
probably not the best way to go about it, but it will work.
EDIT
Ok in viewDidAppear:
AppDelegate *appDelegate = [UIApplication sharedApplication].delegate;
if ([appDelegate.stringForTextField isEqualToString:#""]){
self.urlNameInput.text = #"example http";
} else {
self.urlNameInput.text = appDelegate.stringForTextField;
}
Now what this will do is if the user goes to another view controller, and comes back, the text field text will be what the user last entered, unless in another view controller, stringForTextField is updated to some new value. If this still does not work, look at your processPbn method to make sure the if clause is entered and that value is set. Otherwise it will always say "example http"

Answer 3

I'm not understanding why it's unimportant to persist the previous value across application launches, especially when it is beneficial to your users to have it persist only during the application lifecycle. codeInOrange's answer works by adding a property to the AppDelegate. The only thing I would add to his answer is a conditional if() . If you want to do it without any properties, you can still use the NSUserDefaults.
At the top of your ViewController.m file
#define SetHTTPString(string) [[NSUserDefaults standardUserDefaults]setObject:string forKey:#"HTTPString"] //no semicolon
#define GetHTTPString() [[NSUserDefaults standardUserDefaults]objectForKey:#"HTTPString"] //no semicolon
Then, in viewWillAppear...
-(void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
NSString *httpString = GetHTTPString();
if (httpString) {
self.urlNameInput.text = httpString;
} else {
self.urlNameInput.text = #"Example http";
}
}
Next, in the method where the user enters text and "enters it"
...methodToEnterURL {
SetHTTPString(self.urlNameInput.text);
}
Finally, if you absolutely want to destroy the value in the NSUserDefaults, add this method to your AppDelegate's didEnterBackground method:
[[NSUserDefaults standardUserDefaults]setObject:#"Example http" forKey:#"HTTPString"];

Answer 4

This is a perfect usage for NSUserDefaults. When the user enters something just store it in NSUserDefaults. Check to see if the NSUserDefaults entry is blank on each launch, and if so just display the original string.
Save the text in NSUserDefaults with something like:
[[NSUserDefaults standardUserDefaults]setObject:#"yourNewString" forKey:#"userTextEntered"];
And then just check it on each launch:
if([[NSUserDefaults standardUserDefaults] objectForKey:#"userTextEntered"])
{
//display the user entered string
}
else
{
//display the string that you want to display prior to text being entered
}
However, this solution is only necessary if you want to preserve the text between application shutdowns and launches.

Answer 5

The code below assumes that the Storyboard contains the initial, default Text (of at least 3 characters length).
I really appreciated the help I got from others, especially from codeInOrange . I actually believe this is codeInOrange's solution, but I was never able to quite put his pieces together until I finally stumbled upon this one.
I hope this is really a valid answer, and apologize to all if I did not state my question clearly or if I mistook others' valid answers, especially codeInOrange.
//
// ViewController.m
// StickyPlaceholder
//
//
#import "ViewController.h"
#interface ViewController ()
#end
#implementation ViewController
#synthesize textInput;
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
AppDelegate *appDelegate = [UIApplication sharedApplication].delegate;
if (!appDelegate.stringForTextField)appDelegate.stringForTextField = self.textInput.text ;
}
- (BOOL)textFieldShouldReturn:(UITextField *)textField {
AppDelegate *appDelegate = [UIApplication sharedApplication].delegate;
if (textField == self.textInput) {
[textField resignFirstResponder];
// next line is dummy processing
if (self.textInput.text.length>2)appDelegate.stringForTextField = self.textInput.text;
}
return YES;
}
- (void)viewDidAppear:(BOOL)animated
{
AppDelegate *appDelegate = [UIApplication sharedApplication].delegate;
self.textInput.text = appDelegate.stringForTextField;
}
#end