ButtonGroupData.verticalIndex constructor

ButtonGroupData.verticalIndex(int index, int length)

Creates group data for a button at index in a vertical group of length buttons.

Returns:

• verticalTop for the first button (index 0)
• zero for middle buttons
• verticalBottom for the last button
• none if group has only one button

Implementation

factory ButtonGroupData.verticalIndex(int index, int length) {
  if (length <= 1) {
    return none;
  } else {
    if (index == 0) {
      return verticalTop;
    } else if (index == length - 1) {
      return verticalBottom;
    } else {
      return zero;
    }
  }
}