Question

I have an IPad apllication in which I need to make a number pad type keyboard in my view. With a textfield and 9 numbers.and a back press button. I had achieved this with 9 buttons and a text field.In each of the button action I am appending that digit to the text field value like this:

[number setText:[number.text stringByAppendingString:@"9"]];

Now I need to change the background of the button when textfield.length equall to 9. Otherwise the same. For that i include a check in my each button actions like this.

if ([number.text length]==9)
{
    [button setBackgroundImage:[UIImage imageNamed:@"active.png"] forState:UIControlStateNormal];
}
else 
{
    [button setBackgroundImage:[UIImage imageNamed:@"inactive.png"] forState:UIControlStateNormal];
}

before upending the next i am checking this.but it is changing the background at 9 digits only if include [number.text length]==8.and in the back trace button i am removing the last appended digit by

if ( [number.text length] > 0)
{
    number.text = [number.text substringToIndex:[number.text length] - 1];
}

Here I am checking the digits after the operation.then it is taking the correct length.

can any body help me?

Answer 1

-(IBAction)yourAddNewCharacterMethod:(id)sender
{
    if([number.text length] < 9)
    {
        [number setText:[number.text stringByAppendingString:@"9"]];
        if([number.text length] == 9)
        {
            [button setBackgroundImage:[UIImage imageNamed:@"active.png"] forState:UIControlStateNormal];
        }
        else
        {
            [button setBackgroundImage:[UIImage imageNamed:@"inactive.png"] forState:UIControlStateNormal];
        }
    }
}

You will have to check same on each button click.
And this is your deleteButtonClickedMethod

-(void)deleteButtonClickedMethod
 {
     if([number.text length] > 0)
     {
        [number deleteBackward];
     }
 }

No need to use substringToIndex:.