Andengine，我如何保持球弹起相同高度？

Question

I'm trying to keep a ball bouncing the same height each time it bounces like doodle jump. but when the ball reaches the platform it decelerates to an inch each bounce and slowly gains speed. My question is how to keep its height permanent no matter what it bounces on. This is my ball and platform(the platform is in the sky) http://imgur.com/WIyfRJ7 here are my physics for my platform and ball

final FixtureDef PLAYER_FIX = PhysicsFactory.createFixtureDef(10.0f, 1.2f, 0.0f);
    body = PhysicsFactory.createCircleBody(physicsWorld, sPlayer, BodyType.DynamicBody, PLAYER_FIX );


final FixtureDef PLATFORM_FIX = PhysicsFactory.createFixtureDef(10.0f, 0.85f, 0.0f);
    PlatformBody = PhysicsFactory.createBoxBody(physicsWorld, Platform, BodyType.KinematicBody, PLATFORM_FIX);

Answer 1

To bounce the ball at the same height, do the following

The value of restitution varies between 0 and 1. 1 means the ball's velocity will be exactly reflected and 0 means it won't bounce.

Set the fixture's restitution to 1.0f

For more details you can refer to http://www.box2d.org/manual.html

Hope it helps.