dart - Flutter AbsorbPointer vs IgnorePointer difference

Question

What is the difference between AbsorbPointer and IgnorePointer in flutter?

Docs mention:

AbsorbPointer prevents its subtree from receiving pointer events by terminating hit testing at itself.

IgnorePointer, which also prevents its children from receiving pointer events but is itself invisible to hit testing.

I didn't get what is the real life difference between the two.

Answer 1

The difference is when we have two widgets overlapping each other, that can both receive clicks.

Consider a red and blue square, both clickable, where the blue square is smaller and on the top of the red square:

Stack(
  alignment: Alignment.center,
  children: [
     Container(color: Colors.red),
     Container(width: 42, height: 42, color: Colors.blue),
  ],
)

By default, without IgnorePointer/AbsorbPointer, tapping the blue square will send a click event on blue and red gets nothing.

In that situation, wrapping blue square into an AbsorbPointer means that when tapping the blue square, neither the blue square nor the red one gets the click event.

If we instead used an IgnorePointer, the red square would receive click events when tapping the blue square.