Objective-C: Adding UIButtons programmatically from another class

I'm having trouble connecting the dots between code and .xib files.

If I want to add a series of UIButtons programmatically to my view controller, how would I go about doing this from a separate class?

For instance, if I have MainViewController.m, which is set 开发者_StackOverflowas the root view controller in Xcode, how can I add a UIButton to that view controller from SecondViewController.m? Is this even possible?

I would essentially like to place all of my "user interface" code in a separate class.

Thanks

To do this, create a UIButton *myButton programmatically and then call [mainViewController addSubview:myButton];. This may mean you need to store a MainViewController * property in your SecondViewController class.

Important methods and properties for a UIButton instance (essentially, just take a look at the documentation, but here's a minimal set of stuff to get you started):

• +[UIButton buttonWithType:buttonType] - Make sure if you're doing anything remotely custom to use UIButtonTypeCustom here (it doesn't give you any default background images or otherwise to have to nil out)

• setFrame: - Position the button relative to its container and set the size, for usability reasons the width and height should be at least 44 pixels (as mentioned here).

• setTitle:forState: - UIControlStateNormal will act as the default properties for other states too, so you may only need to set the text here

• setBackgroundImage:forState: - use UIControlStateNormal and UIControlStateHighlighted/UIControlStateSelected primarily, UIControlStateDisabled if you wish to show it grayed out or inaccessible at any point.

• setImage:forState: - Use for an icon next to the button text (like an arrow pointing down for Save or up for Load, etc)

• setEnabled:, setHidden:, setSelected: - Transition between different button states. setHighlighted: happens automatically when you tap the button.

• addTarget:self action:@selector(buttonClicked:) forControlEvents:UIControlEventTouchUpInside - TouchUpInside is almost always what you want for a simple button press, I'm using a method named buttonClicked: here to handle my button press.

Oh, and if you use [[UIButton alloc] initWith...] don't forget to [myButton release] once it's added to the mainViewController :)

use this

 #import "MainViewController.h"

@interface SecondViewController
{
  MainViewController *mainView;
}

@property(nonatomic, retain)  MainViewController *mainView;

-(void)addButtons;

In your implementation

@synthesize mainView;

-(void)addButtons
{
  UIButton *add = [UIButton alloc] init];
//do necessary stuff on button here
[self.mainView addSubview:add];
[add release];
}

In your MainViewcontroller.m

#import "SecondViewController.h"

-(void)viewDidLoad
{
[self superViewDidLoad];
SecondViewController *second = [SecondViewController alloc] init];
second.mainView = self;
[second addButton];
[second release];
}