如何使用UIButton多次更改标签？

Question

I want to have one UIButton that will change the text of a label in a series. For example, I may have a label that says hello .

Then when i push a button, it will change to, What's up? .

But then a second tap of the same button will change the label to Nuttin' much! .

I know how to make the text of a label change once, but how do I change it many times with the same button? Preferably, anywhere around 20 to 30 separate texts.

Thank you in advance! :D

Answer 1

That's pretty open ended. Consider adding a property to your class which is an index into an array of strings. Each time you push the button increment the array (modulo size of array) and use the corresponding string to update the button. But there are a lot of other ways you could do this...

Answer 2

What happens when the app runs out of phrases? Start over? The typical approach would look like this.

@property (strong, nonatomic) NSArray *phrases;
@property (assign, nonatomic) NSInteger index;

- (IBAction)pressedButton:(id)sender {

    // consider doing this initialization somewhere else, like in init
    if (!self.phrases) {
        self.index = 0;
        self.phrases = @{ @"hello", @"nuttin' much" };  // and so on
    }

    self.label.text = self.phrases[self.index];
    self.index = (self.index == self.phrases.count-1)? 0 : self.index+1;
}

Answer 3

In the viewDidLoad method, create an array with strings to hold the labels. Then create a variable to keep track of which object should be set as the current label. Set the initial text:

NSArray *labelNames = [[NSArray alloc] initWithObjects:@"hello",@"what's up?", @"nuttin much"];
int currentLabelIndex = 0;
[label setText:[labelNames objectAtIndex:currentLabelIndex]];

Then in the method that gets called when the button is tapped, update the text and the index.

- (IBAction) updateButton:(id)sender {

    // this finds the remainder of the division between currentLabelIndex+1 and labelNames.count. If it is less than the count, its just the index. If its equal to the count we go back to the beginning of the array.
    currentLabelIndex = (currentLabelIndex+1)%labelNames.count;

    [label setText:[labelNames objectAtIndex:currentLabelIndex]];

}