碰撞后精灵不在屏幕上

Question

When the game starts the ball will bounce off the edges perfectly using this code:

    if (Is_hit == true && ballFired == true )
    {
        //collision here
        ballXPos = 960 - ballimg.Width - (ballXPos - 960 + ballimg.Width);
        ballXDir = +1;

        ballYDir = -1;
    }

    if (Ballvisible == true)
    {


        if (Keyboard.GetState().IsKeyDown(Keys.Space) && ballFired == false)
        {
            ballFired = true;

        }
        if (ballFired == true)
        {


            ballXPos = ballXPos - (ballSpeed * ballXDir);

            ballYPos = ballYPos + (ballSpeed * ballYDir);

        }
        if (ballXPos < 0)
        {
            ballXPos = -ballXPos;
            ballXDir = -1;


        }
        if (ballXPos > 960 - ballimg.Width)
        {
            ballXPos = 960 - ballimg.Width - (ballXPos - 960 + ballimg.Width);
            ballXDir = +1;


        }
        if (ballYPos < 0)
        {
            ballYPos = +ballYPos;
            ballYDir = +1;

        }
      if (ballYPos > 700 - ballimg.Height)
      {
          Ballvisible = false;
      }


  }
  if (Ballvisible == false)
  {

      ballSpeed = 3;
      ballXDir = -1;
      ballYDir = -1;

      ballXPos = 450;
      ballYPos = 590;
      ballFired = false;
      Ballvisible = true;
  }



}

but once a collision has occurred the ball will bounce off another sprite(the player paddle) successfully but then the program seems to ignore this code and the ball will go straight off the screen.

collision code:

  // paddle collison detection 
            if   
   (  gameball.PositionRectangle_ball.Intersects(paddle.PositionRectangle_paddle))
            {

     collision_paddle = true; 
                gameball.CheckCollision(collision_paddle); // passes the collision bool value 
            }

Answer 1

It looks like you forgot to clear the Is_hit flag.

If you don't need to check it anywhere else you can clear it in the first block of the posted code:

if (Is_hit == true && ballFired == true )
{
    //collision here
    ballXPos = 960 - ballimg.Width - (ballXPos - 960 + ballimg.Width);
    ballXDir = +1;

    ballYDir = -1;
    Is_hit = false;
}