Use a text field to set the value of a variable

Question

I have a few NSTextFields in my XIB. I created the action for one of my text fields, and it looks like

- (IBAction)setXPos:(id)sender;

In my AppDelegate.h file, I also created an int named XPos. In my AppDelegate.m file, I am having trouble setting the value of XPos to be what I type into the text field. Any help here? Do I need to do a

@property

in my AppDelegate.h? My current code looks like this:

XPos = sender;

But it errors.

First, you don't usually set variables in AppDelegate, for what it looks you might wanna set them in your ViewController.. — valbu17, Jan 27 '15 at 03:02
@NorthBlast I don't have a viewcontroller. all I have are the app delegate. This is a mac app btw — XtremeHek3r, Jan 27 '15 at 03:17
@Jason You might have done something wrong because I just created a dummy mac app and it contains/creates the ViewController.. Create new project -> OS X (Application) -> Cocoa Application -> Next -> ProjectName -> Create.. Done! — valbu17, Jan 27 '15 at 03:29
What is the IBAction Code? Generally speaking (XPos is a float or a number), you might want to drop a number formatter in your NSTextField, but in any event getting a numeric value is easy enough. Post the IBAction code, and we can help. — jwlaughton, Jan 27 '15 at 04:09

jwlaughton · Accepted Answer · 2015-01-27T04:43:25.673

1

This is quite simple. In your .h file:

@interface AppDelegate : NSObject <NSApplicationDelegate>

{
    IBOutlet NSTextField *xPosTextBox;
}

- (IBAction)setXPos:(id)sender;

Be sure you connect both to your NSTextField in IB. For the next step I'll assume you have a number formatter in the text box and that xPos is a double. In applicationDidFinishLaunching:

[[xPosTextBox formatter] setFormat:@"##0.000"];
[xPosTextBox setDoubleValue:myInitialValue];

Then somewhere in your AppDelegate code add a method:

- (IBAction)setXPos:(id)sender
{
     xPos = [xPosTextBox doubleValue];
}

easy.

if you have a float in applicationDidFinishLaunching:

[[xPosTextBox formatter] setFormat:@"##0.000"];
[xPosTextBox setFloatValue:myInitialValue];

Then the IBAction method:

- (IBAction)setXPos:(id)sender
{
     xPos = [xPosTextBox floatValue];
}

If you have an int (or NSInteger), no need for the number formatter, so in applicationDidFinishLaunching:

[xPosTextBox setIntValue:myInitialValue];
// [xPosTextBox setIntegerValue:myInitialValue]; for NSInteger

Then the IBAction method:

- (IBAction)setXPos:(id)sender
{
     xPos = [xPosTextBox intValue];
    // xPos = [xPosTextBox integerValue]; for NSInteger
}

edited Jan 27 '15 at 04:43

answered Jan 27 '15 at 04:28

jwlaughton

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Is it possible to do this with a float or int? – XtremeHek3r Jan 27 '15 at 04:32
You are the best! Apple makes the control+drag kinda confusing to a novice programmer like me. – XtremeHek3r Jan 27 '15 at 04:39
Also, does this keep checking the value, or does it check only once (in `applicationDidFinishLaunching:` – XtremeHek3r Jan 27 '15 at 04:42
Sorry for all the questions, but where did the myInitialValue come from? Is it already defined? (it's late and ill probably implement this in the morning/after school.) – XtremeHek3r Jan 27 '15 at 04:45
I've edited my post. In IB if you select this text field then in the Attributes inspector you can choose when the IBAction will be called. I typically choose "Send on end editing", which will call the IBAction either when the user hits enter or tabs away from the field. – jwlaughton Jan 27 '15 at 04:47
myInitialValue is just a dummy I put there. I assume you want to set the text box to some initial value when it's first displayed. If you've initialized xPos, you could substitute xPos for myInitialValue. – jwlaughton Jan 27 '15 at 04:50

Use a text field to set the value of a variable

1 Answers1