Checkbox in iOS application

Question

I need to add checkbox controls to my form. I know that there is no such control in iOS SDK. How could I do this?

Answer 1

I wanted to do this programmatically, and also solve the problem that the hit area was really too small. This is adapted from various sources, including Mike and Mike's commenter Agha.

In your header

@interface YourViewController : UIViewController {
    BOOL checkboxSelected;
    UIButton *checkboxButton;
}

@property BOOL checkboxSelected;;
@property (nonatomic, retain) UIButton *checkboxButton;

-(void)toggleButton:(id)sender;

And in your implementation

// put this in your viewDidLoad method. if you put it somewhere else, you'll probably have to change the self.view to something else
// create the checkbox. the width and height are larger than actual image, because we are creating the hit area which also covers the label
UIButton* checkBox = [[UIButton alloc] initWithFrame:CGRectMake(100, 60,120, 44)];  
[checkBox setImage:[UIImage imageNamed:@"checkbox.png"] forState:UIControlStateNormal];
// uncomment below to see the hit area
// [checkBox setBackgroundColor:[UIColor redColor]];
[checkBox addTarget:self action:@selector(toggleButton:) forControlEvents: UIControlEventTouchUpInside];
// make the button's image flush left, and then push the image 20px left
[checkBox setContentHorizontalAlignment:UIControlContentHorizontalAlignmentLeft];
[checkBox setImageEdgeInsets:UIEdgeInsetsMake(0.0, 20.0, 0.0, 0.0)];
[self.view addSubview:checkBox];

// add checkbox text text
UILabel *checkBoxLabel = [[UILabel alloc] initWithFrame:CGRectMake(140, 74,200, 16)];
[checkBoxLabel setFont:[UIFont boldSystemFontOfSize:14]];
[checkBoxLabel setTextColor:[UIColor whiteColor]];
[checkBoxLabel setBackgroundColor:[UIColor clearColor]];
[checkBoxLabel setText:@"Checkbox"];
[self.view addSubview:checkBox];

// release the buttons
[checkBox release];
[checkBoxLabel release];

And put this method in too:

- (void)toggleButton: (id) sender
{
    checkboxSelected = !checkboxSelected;
    UIButton* check = (UIButton*) sender;
    if (checkboxSelected == NO)
        [check setImage:[UIImage imageNamed:@"checkbox.png"] forState:UIControlStateNormal];
    else
        [check setImage:[UIImage imageNamed:@"checkbox-checked.png"] forState:UIControlStateNormal];

}