在類之間加載X位置會給出“字段從未分配給”警告

Question

因此，我在XNA上創建了一個小游戲，目前正處於AI編碼階段。 我目前遇到的問題是，我無法加載redNinja（玩家角色）的X位置，並且無法讓blueNinja（AI）讀取並走向它。

每次我嘗試通過redNinja.Position.X進行引用時，它都會為我提供field is never assigned to, and will always have it's default value null.的field is never assigned to, and will always have it's default value null. 警告。

namespace Ninja_DM
{
class AI
{
    Texture2D blueNinja;
    Ninjas redNinja;
    float timer = 0f;
    float interval = 130f;
    int currentFrame = 0;
    int spriteSpeed = 2;
    int spriteWidth = 32;
    int spriteHeight = 28;
    public Rectangle sourceRect;
    Vector2 position_b;
    Vector2 origin;

    public Vector2 Position
    {
        get { return position_b; }
        set { position_b = value; }
    }

    public Vector2 Origin
    {
        get { return origin; }
        set { origin = value; }
    }

    public Texture2D Texture
    {
        get { return blueNinja; }
        set { blueNinja = value; }
    }

    public Rectangle SourceRect
    {
        get { return sourceRect; }
        set { sourceRect = value; }
    }

    public AI(Texture2D texture, int currentFrame, int spriteWidth, int spriteHeight)
    {
        this.blueNinja = texture;
        this.currentFrame = currentFrame;
        this.spriteWidth = spriteWidth;
        this.spriteHeight = spriteHeight;
    }

    public void AIMovement(GameTime gameTime)
    {
        sourceRect = new Rectangle(30 * currentFrame, 0, 30, 37);

        if (position_b.X > redNinja.Position.X)
        {
            AnimateLeftAI(gameTime);
            if (position_b.X < 20)
            {
                position_b.X += spriteSpeed;
            }
        }

        if (position_b.X < redNinja.Position.X)
        {
            AnimateRightAI(gameTime);
            if (position_b.X < 1100)
            {
                position_b.X += spriteSpeed;
            }
        }

    }

    public void AnimateLeftAI(GameTime gameTime)
    {

        timer += (float)gameTime.ElapsedGameTime.TotalMilliseconds;

        if (timer > interval)
        {
            currentFrame++;

            if (currentFrame > 4)
            {
                currentFrame = 3;
            }
            timer = 0f;
        }
    }

    public void AnimateRightAI(GameTime gameTime)
    {

        timer += (float)gameTime.ElapsedGameTime.TotalMilliseconds;

        if (timer > interval)
        {
            currentFrame++;

            if (currentFrame > 4)
            {
                currentFrame = 3;
            }
            timer = 0f;
        }
    }
}
}

Answer 1

您需要在調用AIMovement（）時將玩家的忍者作為參數，如下所示：

public void AIMovement(GameTime gameTime, Ninjas playerNinja)
{
    sourceRect = new Rectangle(30 * currentFrame, 0, 30, 37);

    if (position_b.X > playerNinja.Position.X)
    {
        AnimateLeftAI(gameTime);
        if (position_b.X < 20)
        {
            position_b.X += spriteSpeed;
        }
    }

    if (position_b.X < playerNinja.Position.X)
    {
        AnimateRightAI(gameTime);
        if (position_b.X < 1100)
        {
            position_b.X += spriteSpeed;
        }
    }

}

注意，您實際上不再需要聲明一個名為redNinja的字段變量，因為您將Ninjas作為測試的對象作為方法的參數/參數。