determine if text field has focus or not

I am writing an if statement for an ios app and I want change the picker, based on which text field currently has focus. here is what I have so far.

func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int {
    return 1
}

func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {

    if (condition) {
        return array1.count
    }else{
        return array2.count
    }
}

func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {

    if (condition) {
        textBox1.text = array1[row]
    }else{
        textBox2.text = array2[row]
    }
}

func pickerView(pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {

    if (condition) {
        return array1[row]
    }else{
       return array2[row]
    }
}