isSingleButton function Null safety

bool isSingleButton(
  1. int buttons
)

Returns whether buttons contains one and only one button.

The buttons parameter is a bit field where each set bit represents a button. This function returns whether there is only one set bit in the given integer.

It returns false when buttons is zero.

Example:

  assert(isSingleButton(0x1) == true);
  assert(isSingleButton(0x11) == false);
  assert(isSingleButton(0) == false);

See also:

  • smallestButton, which returns the button in a buttons bit field with the smallest integer button.

Implementation

bool isSingleButton(int buttons) => buttons != 0 && (smallestButton(buttons) == buttons);