Why are didBeginContact called multiple times?

Question

In an iOS game that uses Sprite Kit along with the contact detection in Sprite Kit\'s build-in physics engine, I decrease the Hero\'s number lives by one each time he gets i

Answer 1

I figured out easy solution:

Just change either body's categoryBitMask value to 0 or non-used value right after it detected contact.

For example:

if (firstBody.categoryBitMask == padCategory && secondBody.categoryBitMask == colorBallCategory) {

      secondBody.categoryBitMask = 0;

      // DO OTHER THING HERE

}