XNA无法创建多个实例？

Question

我正在尝试构建一个非常简单的XNA项目。 每隔5秒钟就会产生一个新球，这将会弹出墙壁。 由于某些原因，它不会创建我的球的多个实例。我似乎无法弄清楚我做错了什么。

希望这里有人能帮我发现我的错误。

这里是我的代码Game1.cs类

using System; 
using System.Collections.Generic; 
using System.Linq; 
using Microsoft.Xna.Framework; 
using Microsoft.Xna.Framework.Audio; 
using Microsoft.Xna.Framework.Content; 
using Microsoft.Xna.Framework.GamerServices; 
using Microsoft.Xna.Framework.Graphics; 
using Microsoft.Xna.Framework.Input; 
using Microsoft.Xna.Framework.Media; 

namespace BallBounce 
{ 
/// <summary> 
/// This is the main type for your game 
/// </summary> 
public class Game1 : Microsoft.Xna.Framework.Game 
{ 
    GraphicsDeviceManager graphics; 
    public static SpriteBatch spriteBatch; 

    Ball ball; 
    Ball ball2; 

    Ball[] balls; 
    int maxBalls = 1; 

    Texture2D ballTexture; 
    Texture2D ballTexture2; 

    Vector2 position; 
    Vector2 position2; 

    int spawnTime = 0; 

    public Game1() 
    { 
     graphics = new GraphicsDeviceManager(this); 
     Content.RootDirectory = "Content"; 
    } 

    /// <summary> 
    /// Allows the game to perform any initialization it needs to before starting to run. 
    /// This is where it can query for any required services and load any non-graphic 
    /// related content. Calling base.Initialize will enumerate through any components 
    /// and initialize them as well. 
    /// </summary> 
    protected override void Initialize() 
    { 
     // TODO: Add your initialization logic here 
     ballTexture = Content.Load<Texture2D>("Bitmap1"); 
     ballTexture2 = Content.Load<Texture2D>("Bitmap2"); 

     Random r = new Random(); 
     int randomNumberX = r.Next(0, 400); 
     int randomNumberY = r.Next(0, 400); 

     position = new Vector2(randomNumberX, randomNumberY); 
     position2 = new Vector2(randomNumberY, randomNumberX); 

     ball = new Ball(this, ballTexture, position); 
     ball2 = new Ball(this, ballTexture2, position2); 

     Components.Add(ball); 
     // Components.Add(ball2); 

     base.Initialize(); 
    } 

    /// <summary> 
    /// LoadContent will be called once per game and is the place to load 
    /// all of your content. 
    /// </summary> 
    protected override void LoadContent() 
    { 
     // Create a new SpriteBatch, which can be used to draw textures. 
     spriteBatch = new SpriteBatch(GraphicsDevice); 

     // TODO: use this.Content to load your game content here 
    } 

    /// <summary> 
    /// UnloadContent will be called once per game and is the place to unload 
    /// all content. 
    /// </summary> 
    protected override void UnloadContent() 
    { 
     // TODO: Unload any non ContentManager content here 
    } 

    /// <summary> 
    /// Allows the game to run logic such as updating the world, 
    /// checking for collisions, gathering input, and playing audio. 
    /// </summary> 
    /// <param name="gameTime">Provides a snapshot of timing values.</param> 
    protected override void Update(GameTime gameTime) 
    { 
     // Allows the game to exit 
     if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed) 
      this.Exit(); 

     // TODO: Add your update logic here 
     spawnTime += (int)gameTime.ElapsedGameTime.Milliseconds; 
     // Console.WriteLine(spawnTime + " " + maxBalls); 
     if(spawnTime >= 500) 
     { 
      maxBalls += 1; 

      for(int i = 0; i < maxBalls; i++) 
      { 
       //balls[i] = new Ball(this,ballTexture); 
       //Components.Add(balls[i]); 
      } 

      spawnTime = 0; 
     } 

     base.Update(gameTime); 
    } 

    /// <summary> 
    /// This is called when the game should draw itself. 
    /// </summary> 
    /// <param name="gameTime">Provides a snapshot of timing values.</param> 
    protected override void Draw(GameTime gameTime) 
    { 
     GraphicsDevice.Clear(Color.CornflowerBlue); 

     // TODO: Add your drawing code here 

     base.Draw(gameTime); 
    } 
} 

}

这里是我的Ball.cs：

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Text; 
using Microsoft.Xna.Framework; 
using Microsoft.Xna.Framework.Graphics; 

namespace BallBounce 
{ 
public class Ball : Microsoft.Xna.Framework.DrawableGameComponent 
{ 
    Texture2D texture; 
    Vector2 speed = new Vector2(4,6); 
    Vector2 position; 
    Color color = Color.Blue; 

    public Ball(Game1 game, Texture2D texture, Vector2 position) 
     : base(game) 
    { 
     this.texture = texture; 
     Console.WriteLine("=========================BAL---------------"); 

     this.position = position; 

     Random random = new Random(); 

     int red = random.Next(0, 255); 
     int green = random.Next(0,255); 
     int blue = random.Next(0,255); 

     color = new Color(red,green,blue); 

     Console.WriteLine(position); 

    } 

    public override void Update(GameTime gameTime) 
    { 
     this.position = this.position += speed; 

     if (this.position.Y >= (GraphicsDevice.Viewport.Height - this.texture.Height)) 
     { 
      speed.Y = speed.Y * -1; 
     } 
     if (this.position.Y <= 0) 
     { 
      speed.Y = speed.Y * -1; 
     } 
     if (this.position.X >= (GraphicsDevice.Viewport.Width - this.texture.Width)) 
     { 
      speed.X = speed.X * -1; 
     } 
     if (this.position.X <= 0) 
     { 
      speed.X = speed.X * -1; 
     } 

    } 

    public override void Draw(GameTime gameTime) 
    { 
     Game1.spriteBatch.Begin(); 
     Game1.spriteBatch.Draw(texture, position, color); 
     Game1.spriteBatch.End(); 

     base.Draw(gameTime); 
    } 
} 

}

Answer 1

它看起来像你重新创建一些数组中的所有球，每500毫秒增加一个（真的是0.5秒）。您应该只添加一个新球到一些全局球的列表中，而不是像现在这样重写所有现有的球。

所以我猜你可以这样做：

if(spawnTime >= 500) 
{ 
    Components.Add(new Ball(this, ballTexture));    

    spawnTime = 0; 
} 

你的做法并不好看，但。您确定要直接添加球到Components吗？