以一种编程方式将数据从一个viewcontroller传递到现有的viewcontroller

Question

Recently I am stuck in a problem so that I cannot move on to the next coding part. There are two view controllers(let's say the first.m and second.m) and I would like to pass parameter data from one to another view controller without using storyboard. But the tricky part for me is the second view controller was already initiated in the AppDelegate.m file.

I can pass data if I have initiated the second view controller in the first view controller with some importing header file, for example..

@import "Second.h"

Second *secondView = [[Second alloc] initWithNibName:@"SecondNib" bundle:nil];
secondView.someStringValue = @"passThisString";

However, this coding makes a new second view controller, which is not what I want. I found there is a something like

myAppDelegate *appDelegate = (myAppDelegate *)[[UIApplication sharedApplication] delegate];

to connect to the AppDelegate.m file. But after a few days struggling with this my brain is getting blackout. Please give me any advice.. Is there a way to pass data to existing view controller without using storyboard? or any way through AppDelegate to Second view controller. Any help will be appreciated

Answer 1

@jazzed28 you can do this without initiating your Second . You just need to access the already initiated Second . So declare Second in myAppDelegate.h as a property of it like this -

@property (nonatomic, strong) Second *svc;

then whenever you need second you can access like this -

myAppDelegate *appDelegate = (myAppDelegate *)[[UIApplication sharedApplication] delegate];

appDelegate.svc

Answer 2

crete two class methods in myAppDelegate for setting data and getting data from Appdelegate,you can access those methods by using APpdelegate class name.

 Setter method
 +(void)setGlobalString:(NSString *)stringgValue{
          [[NSUserDefaults standardUserDefaults] setObject:stringgValue forKey:@"globalValue"];
     // you can save string value here by using NSUserDefaults or any thing else

    }
Getter method
+(NSString *)getGlobalString{
        return [[NSUserDefaults standardUserDefaults] forKey:@"globalValue"];
    }

you can call methods like

[myAppDelegate setGlobalString:yourString];

NSString *str = [myAppDelegate getGlobalString];

Answer 3

This question has been asked many times before, including on StackOverflow. If you had spent some more time looking for an answer, you might have found this answer for example.