Subtract one from integer displayed in UILabel

I have a UILabel that adds one to its value -- basically it counts up -- when a button is pressed. Could someone please help me with a minus button? That way if the user accidentally presses the add 开发者_运维知识库button more than they needed, they can subtract their mistake. I've tried this, but the label's text is set to -1 now. and I want it to just subtract one each time its pressed:

- (IBAction)subtractButton:(id)sender {
    static int integerSaved;
    integerSaved = integer;
    integerSaved -= 1;
    [label2 setText:[NSString stringWithFormat:@"%i", integerSaved]];
}

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Try this:

- (IBAction)subtractButton:(id)sender {
[label2 setText:[NSString stringWithFormat:@"%d",[label2.text intValue] - 1]];
}

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-(void)subtract
{
   label2.text = [NSString stringWithFormat:@"%d", [label2.text intValue]-1];
}

This code assumes that you are not using Interface Builder, and that you are manually linking "subtract" to the UIButton. If you are using Interface Builder, try this code.

-(IBAction)subtract:(id)sender
{
   label2.text = [NSString stringWithFormat:@"%d", [label2.text intValue]-1];
}

I have not tested this but I think it should work. Good luck!

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Using the value of the UIView instance to do arithmetic is not the MVC-way. You should really be separating your data model from your view.

Expose an int, NSInteger or NSNumber property in a class somewhere, where that class is dedicated to holding data values for your app.

When a touch event comes in for a given button, increment the data property and fire a notification that updates the view based on what's in the property. Or add an observer to the property. The observer then updates the view when the property value changes.

Following the MVC pattern would be a more "Apple"-ish or "iOS"-ish way of doing things, than getting the UIView's value, converting it to an integer, and then converting it back to a string.