Hi i am trying to pass the value from my UITextfield that is declared and being used in my ViewController over to an NSObject I have created that needs the value in it to perform an operation. I'm just not sure what I have to do, I have tried this
I have declared the UITextField in my ViewControllers header file and created an IBOutlet for it.
Then I have #imported this into my NSObject and tried to call it like this
NSString *tempTextField = regTextField.text;
and its getting a error 'regTextField not defined'.
If regTextField is defined in your ViewController subclass, then you probably want to set the text field in your NSObject from your view controller. I would import your NSObject into the view controller and then have an NSString property in your NSObject that you can set from the viewController.
myClass.fieldIWantToSet = self.regTextField.text;
Hope this helps.
Related
i've been doing a thing here using objective-c, but i'm a beginner in this language, and that's what i did:
there is a class, named "firstviewclass", that is in the control of my first view, in this view there is a textfield that the user puts a number. the textfield is in the firstviewclass.h named "setNumber". There is another class, named "secondviewclass" that is in control of the second view, in this view there is a label that is in the secondviewclass.h, and i want that this label recive the value that the user put in the textfield from the first view, but when i test it on the iOS simulator any number that i put in the textfield it appears in the label as 0... I really don't know what to do!
My codes:
firstviewclass.h:
#import <UIKit/UIKit.h>
#interface firstviewclass : UIViewController
#property (strong, nonatomic) IBOutlet UITextField *setNumber;
- (IBAction)gotonextview:(id)sender;
#end
secondviewclass.h:
#import <UIKit/UIKit.h>
#import "firstviewclass.h"
#interface secondviewclass : UIViewController
#property (weak, nonatomic) IBOutlet UILabel *labelthatrecivesthetextfieldvalue;
#end
secondviewclass.m:
#import "secondviewclass.h"
#import "firstviewclass.h"
#implementation secondviewclass
#synthesize labelthatrecivesthetextfieldvalue;
-(void)viewDidLoad{
[super viewDidLoad];
firstviewclass *object = [[firstviewclass alloc] init];
NSString *string = [[NSString alloc] initWithFormat:#"%i", [object.setNumber.text intValue]];
labelthatrecivesthetextfieldvalue.text = string;
}
#end
First of all, I would strongly recommend not naming a property or instance variable setSomething. It will cause headaches for anyone reading your code because it will always look like you're trying to call a setter. Also, please do capitalize your class names.
Your actual problem is that in viewDidLoad you're creating an instance of firstviewclass, and then trying to get the value from setNumber. That is before the user had any chance to enter anything.
Also, the setNumber outlet in firstviewclass will probably be going nowhere anyway, since you're instantiating that class yourself, instead of loading the NIB.
Edit (ah, Storyboard, d'oh):
For Storyboard, you need to pass the setNumber text field's value to the second view.
First of all, remove the firstviewclass *object = [[firstviewclass alloc] init]; line.
Then, in your first view controller's prepareForSegue method, you can pass the value of the setNumber text field to a property in your your second view controller, and use it from there (e.g. in configureView).
I recommend working through Apple's Storyboard tutorial, it shows exactly what you need to do, step by step. The step you're having issues with right now, passing data to your next view controller, is here.
How are you initiating the setting of the label? From viewDidLoad? If so, then 0 would be correct because you have not set object.setNumber.text to anything. Also, you aren't carrying over the data from your first viewController. You need to let the second viewController know what the number is. Try setting this value in your NSUserDefaults, then in your second viewController, load that value from your defaults.
in the viewDidLoad of secondviewclass, you are creating a new instance of firstviewclass, and then accessing the property of the label. Since you haven't set that to be anything, it will always return zero.
Can you post the implementation of the gotonextview method?
EDIT:
I think you need to be setting the label property from the first view controller. so in your gotonextview method, add this line:
secondviewclass.labelthatrecivesthetextfieldvalue.text = self.setNumber.text;
I admit I'm a little lost in your naming scheme but that might work.
Can anyone tell me how can I show the value from one a UIPickerView in another view? I am storing a value in a label but I have to show this value in a button in another view controller.
Typically you would store the value data in your model when the user closes the second view. and the first view would read the value from the model when it re-appears (or use notifications). Your model data could be a plist, or nsuserdefaults or core-data etc.
Alternatively you could create a reference to the first viewController when you create your second viewController and assign this as a property on the second viewController. Then the second viewController in effect has a "path" to the first viewController:
The first viewController would have a property such as:
NSString *myStr; // in the header
#property (nonatomic, retain) NSString *myStr; // in the header file
#synthesize myStr; // in the implementation file
The second viewController would have a property such as:
firstViewController *firstVC; // in the header
#property (nonatomic, retain) firstViewController *firstVC; // in the header file
#synthesize firstVC; // in the implementation file
When you create the second viewController you would do something like:
secondViewController.firstVC = self; // in the implementation file
Then when you want to update myStr in the first ViewController (from the second viewController) you would do something like:
firstVC = #" my new value "; // in the implementation file
I have 2 view controllers now, And it both got tableviews.
When I choose a row in the second tableview (Using didSelectRowAtIndexPath),
and I want to pass the Information I got in the second View to the first View,
I tried to use delegate&protocol, but don't know why, It didn't work.
And I tried to use class method inside the first class, when I got variable in sencond View,
Call the class method inside the first class. The variable successfully pass to first View,
but when I want to set the Lable's text, it still failed..
Can somebody teach me how to do? thanks!
My protocol&delegate.
This is the second view.
#protocol CategoriesViewControllerDelegate;
#interface CategoriesViewController : UIViewController {
TableViewNewAppDelegate *appDelegate;
id <CategoriesViewControllerDelegate> delegate;
}
#property (nonatomic, assign) id <CategoriesViewControllerDelegate> delegate;
#end
#protocol CategoriesViewControllerDelegate <NSObject>
-(void)backstring:(NSString *)String;
#end
In the .m file , synthesize it
#implementation CategoriesViewController
#synthesize delegate;
didSelectRowAtindexPath
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
CategoryData *CateObj = [appDelegate.CateArray objectAtIndex:indexPath.row];
NSString *Strings = [NSString stringWithString:CateObj.CateTitle];
[delegate backstring:Strings];
[self.parentViewController dismissModalViewControllerAnimated:YES];
}
In the first view controller .h file.
#import "CategoriesViewController.h"
#interface DataController : UIViewController <CategoriesViewControllerDelegate>{
.m file
-(void)backstring:(NSString *)String {
NSLog(#"%#",String);
jCateField.text = String;
}
This is how I do my protocol+delegate. Are there something wrong?
btw, I created a Class method in the first view controller, and use the Class method in the sencond view controller, it succesfully pass variable to first view controller.
But the problem is, I can't set my Label's text inside my Class method, even calling Instance method to set text. Is there any way to solve this problem?
The code you provided seems to be correct. In your case you must set :
#property (nonatomic, assign) id <CategoriesViewControllerDelegate> delegate;
correctly to point to the first view controller which conforms to the protocol you defined :
#import "CategoriesViewController.h"
#interface DataController : UIViewController <CategoriesViewControllerDelegate>{
So it seems that you pushed a CategoriesViewController onto a first DataController, you probably missed to do so just before.
// self is the first view controller
// [myCategoriesViewController setDelegate:self]; old fashion
myCategoriesViewController.delegate = self;
[self presentModalViewController:myCategoriesViewController animated:YES];
This can probably solve your issue. Hope this helps.
Also consider let the first controller dismiss the second.
Here is a link to Apple's documentation.
You could just pass the information straight on to your second view controller;
SecondViewController.h
#interface SecondViewController
{
Information *info;
}
#property (nonatomic, retain) Information *info;
#end
SecondViewController.m
#implementation SecondViewController
#synthesize info;
...
#end
And in your didSelectRowAtIndexPath method;
SecondViewController *controller = [[SecondViewController alloc] initWithNibNamed:#"SecondViewController" bundle:nil];
[controller setInfo:YOUR_INFO_OBJECT];
[self.navigationController pushViewController:controller animated:YES];
[controller release];
Import second view controller header file in the first view controller implementation file. Import first view controller header file in second view controller header file.
Create the property (text/label/whatever) in the first view controller.
Create the property of first view controller in the second view controller.
Create the second view controller instance, set the first view controller property to what you need, push controller to the navigation controller. In the second view controller change whatever you want in the first view controller. Instance methods allowed. Do not forget to release first view controller.
Delegate pattern works in that way too.
View controllers are objects. Objects can have methods that can be called from other objects, and they can have instance variables. ("Delegate" is just a fancy term for this.)
There's no inherent reason why passing data between your view controllers should be hard or complicated, so long as the caller has the address of the callee. (And whether or not a given VC has an XIB is irrelevant.)
It sounds like your real problem is not knowing what to do with the data once it's been passed to the callee.
Stupid question: Is "jCateField" actually connected to the label you want to change, or is it nil? If you created the label from code (since you don't have an XIB), you will need to have stored the created label's address into "jCateField" during the view creation.
Can you post the code for as to ho you are displaying the contents when you come back to 1 st view controller.As here if the log gives you proper value then the issue is with the connection (if taken through iboutlet) or with addsubview .
Do you get nil in label or no value (label is hidden).
I'm reasonably new at the iPhone SDK, so please forgive me if this answer's ridiculously obvious.
I have a ViewController connected to a .xib file (they are called FirstViewController)
I also have a custom class called MyCustomClass. In this class, I have a method like this:
- (void)setTheText {
[myLabel setText:#"foo"];
}
I want to call this method to set the text in a label in FirstViewController.xib
So far, I have done this:
Dragged in an "Object" into Interface Builder, and set the class to: MyCustomClass
Connected up the IBOutlet 'myLabel' from MyCustomClass to a UILabel in the view.
However, when I run the program, and press the button to set the label (which is in FirstViewController.m), something like:
- (IBAction)doSomething:(id)sender {
MyCustomClass *customClass = [MyCustomClass alloc] init];
[customClass setTheText];
}
This doesn't set though. NSLog(#"%#",[myLabel text]); returns (null)
Xcode shows no errors or warnings, what could be wrong?
Thanks,
Michael
Additional Info:
Interface to MyCustomClass.h:
#import <UIKit/UIKit.h>
#interface MyCustomClass : NSObject {
UILabel *myLabel;
}
#property (nonatomic, retain) IBOutlet UILabel *myLabel;
- (void)setTheText;
#end
You don't want to create a new instance of your custom class in your action method.
There are a couple of ways to do what you want.
Option 1 is to give your view controller a reference to your custom object. To do this, create an outlet of type MyCustomClass * in your view controller, connect that outlet to the new object that you created in your XIB file, and then get rid of the allocation in your action method:
- (IBAction)doSomething:(id)sender {
[customClass setTheText];
}
Option 2 is to let your CustomClass handle both the label and the action method. To do this, you can simplify things even further. Put an outlet for the UILabel into your CustomClass, and then simply convert your setTheText method into an action:
- (IBAction)setTheText:(id)sender {
[myLabel setText:#"foo"];
}
Now, connect that action up to your button, and everything should work like a charm.
Note: You should probably use a method name that does not start with "set", since those are commonly used for property setters as part of Cocoa's KVC/KVO system. Instead, I would call it something like changeLabel, or equivalent.
Your instance of customClass here is completely unrelated to the NIB. You've instantiated a new object using +alloc. If you want to modify the specific MyCustomClass in your NIB, then FirstViewController needs an IBOutlet that points to it.
UILabel also have a property called text to set the value, you might find that easier.
myObject.myLabel.text = #"Your text";
well you called your label two things, first a non-ibaction then an ibaction in the property.
I want to allow a pushed to set parentViewController's instance variables. For instance, VC1 (the parent) has a bunch of textfields and what not which are filled from VC2 (the child). VC2 is pushed onto the stack by VC1. I've tried doing like parentViewController.myString = "foo"; however since parentViewController is a UIViewController, I can't edit the myString field.
Basically, my question is "How can I access the parent's instance variables?"
Edit: I tried the solution here: Setting property value of parent viewcontroller class from child viewcontroller? but it is chocked full of syntax errors.
Have the parent view controller subclass UIViewController (e.g. ParentViewController), implement all the properties for instance variables you wish to manipulate, and set the variables as ((ParentViewController *)parentViewController).myString = #"foo";.
E.g.
#interface ParentViewController : UIViewController {
NSString *myString;
}
#property (nonatomic, retain) NSString *myString;
#end
and
#implementation ParentViewController
#synthesize myString;
#end