How to send data like NSString from AppDelegate.m to ViewController.m in Objective C

Question

I need to pass NSString data from AppDelegate.m inside didReceiveRemoteNotification method and send it to my ViewController. I need to put NSLog inside viewDidAppear every time i receive a notification.

Answer 1

This is an expansion to @Himanshu's answer, if you're getting your NSString in your AppDelegate and it's something which you needs to preserve for further use, you can create a property and store it. There are multiple ways which you can follow to store / retrieve the values (example: NSDictionary). So choose the one which will make your life easy in future.

Then you can get a shared object for your AppDelegate and access to that property.

Adding his code to make this for future readers.

1. Add a property in your AppDelegate.h

   @property (strong, nonatomic) NSString *strResponse;

2. Add this in top of the AppDelegate.h (after import statement)

   #define theAppDelegate ((AppDelegate *)[UIApplication sharedApplication].delegate)

3. Update string value.

   Inside AppDelegate.m

   self.strResponse = @"some response";

   Outside AppDelegate.m

   theAppDelegate.strLoadApi = @"some good response";

4. You can access it whenever requires.

   NSLog(@"%@",theAppDelegate.strLoadApi);

_{P.S. This is not the best way to do achieve this. It's actually not recommended but I believe, you're learning iOS. So it's basic for you to start. However, you should read this answer to make your self ready for the future development.}

Answer 2

You can do this by adding a property to the header file of your ViewControler

@property NSString *data;

And then in your AppDelegate.m when you load your ViewController you can set the value of the property

self.YourViewController.data = @"Your String";

Answer 3

Interface:

@interface MyAppDelegate : NSObject  {

}
@property (nonatomic, retain) NSString *myString;
...
@end

and in the .m file for the AppDelegate you would write:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
        MyViewController* mainController = (MyViewController*)  self.window.rootViewController;
        self.myString = @" Here your String ";

        return YES;
}

Then, in viewcontroller.m file you can fetch:

MyAppDelegate *appDelegate = (MyAppDelegate*)[[UIApplication sharedApplication] delegate];
someString = appDelegate.myString;  //..to read
appDelegate.myString = someString;     //..to write
NSLog(@"mystring is :- %@",appDelegate.myString);

Answer 4

add first 3 line in your AppDelegate.h file

#define theAppDelegate \
((AppDelegate *)[UIApplication sharedApplication].delegate)

@interface AppDelegate : UIResponder <UIApplicationDelegate>

@property (strong,nonatomic) NSString* strLoadApi; // create one property that you want to use in another viewcontoller.

Any viewcontoller you can set that value like and must be set before access / get value.

theAppDelegate.strLoadApi = @"Hello";

Any viewcontoller you can get that value like

NSLog(@"%@",theAppDelegate.strLoadApi);

Answer 5

First, you need to take property in AppDelegate.h

@property(nonatomic) NSString *yourProperty;

Then in AppDelegate You assign the value to that property.

Then in your ViewController you can access that Property By:

AppDelegate * del = (AppDelegate*)[UIApplication sharedApplication]. delegate

NSString *str = del.yourProperty

Now use this str to display on UI.

Answer 6

whenever u want to pass NSString add this code

 //find ur viewcontroller and set parameter
 for (UIViewController *view in self.navigationController.viewControllers) {
    if (view isMemberOfClass:[yourViewController class]) {
        yourViewController *yview = (yourViewController *) view;
        yview.parameter = @"string";
        break;
    }
}

in yourViewController set getter setter for parameter

Answer 7

NSString *sData = @"data";
[[NSUserDefaults standardUserDefaults] setObject:sData forKey:@"keyName"];
[[NSUserDefaults standardUserDefaults] synchronize];
to get it back later

NSString *sData = [[NSUserDefaults standardUserDefaults]
    stringForKey:@"keyName"];