question: public void exit ( ) { cancel ( ) ; final float radius = lerp ( 0 , mOuterRadius , mTweenRadius ) ; final float remaining ; if ( mAnimRadius != null && mAnimRadius . isRunning ( ) ) { remaining = mOuterRadius - radius ; } else { remaining = mOuterRadius ; } final int radiusDuration = ( int ) ( 1000 * Math . sqrt ( remaining / ( WAVE_TOUCH_UP_ACCELERATION + WAVE_TOUCH_DOWN_ACCELERATION ) * mDensity ) + 0.5 ) ; final int opacityDuration = ( int ) ( 1000 * mOpacity / WAVE_OPACITY_DECAY_VELOCITY + 0.5f ) ; exitSoftware ( radiusDuration , opacityDuration ) ; }
target:  Starts the exit animation.