Question

I am trying to pass a string back and forth between the view Controllers, so for example as soon as I click on a tab bar button (+) in the first View, second view opens (PresentModalViewController) and it has a Text Field. So anything I type, I take it into a string(this string is an object of the first view) and I am trying to append that string to a tableview loaded in the first View.

Note: My string object is declared like this

View1.h

NSString *string 

@property (copy) NSString *string;

View1.m

@synthesize string;

And in the View 2 I am passing the textField Value like this

View2.m

View1 *view1 = [[View1 alloc] initWithNibName:@"View1" bundle:nil];
view1.string = [[NSString alloc] initWithFormat:@"%@", TextField.text];

Problem – When I NSLog this value inside the View2, it grabs the value from the Text Field but in order for me to load the previous view, I need to dismiss this View2. So as soon as this View2 is dismissed when I try to access the same string object in my view 1. It says the string object is null.

Question – Could someone tell me
1. How to get the text Field value from view 2 to view 1 after dismissing View 2 (does it really makes all its objects null when dismissed?)
2. How to append that string to the last index of a NSMutableArray?

Answer 1

This is a very good question that I also had trouble figuring out when I started coding for the iOS. Basically, you don’t need to initialize a new view1 because the tabbar controller already holds the view1 object in its viewControllers property. Also, alloc/init’ing the string in not necessary in this situation.

Therefore, you would want to change this:

View1 *view1 = [[View1 alloc] initWithNibName:@"View1" bundle:nil];
view1.string = [[NSString alloc] initWithFormat:@"%@", TextField.text];

To something like this:

View1 *view1 = [self.tabbarController.viewControllers objectAtIndex:0];
view1.string = textField.text;

Or even:

((View1 *)[self.tabbarController.viewControllers objectAtIndex:0]).string = textField.text;

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Part 2:

How to append that string to the last index of a NSMutableArray?

NSMutableArray *someArray = [[NSMutableArray alloc] init];
[someArray addObject:string];
[someArray addObject:@"anotherString"];