XNA按钮单击未触发

Question

I created a button class and i am calling it inside main Game class. But it is not firing. Actually i want to firing Update method which inside of Button class when i clicked to left button on the mouse. I am checking all mouse event via Debug.WriteLine everything is looking like normally. What could be wrong?

GameBase class

public class GameBase : Microsoft.Xna.Framework.Game
{
    GraphicsDeviceManager graphics;
    Button btn;

    public GameBase()
    {
        graphics = new GraphicsDeviceManager(this);
        Content.RootDirectory = "Content";
        IsMouseVisible = true;
        graphics.PreferredBackBufferWidth = 600;
        graphics.PreferredBackBufferHeight = 400;
    }
    protected override void Initialize()
    {
        base.Initialize();
    }
    protected override void LoadContent()
    {
        spriteBatch = new SpriteBatch(GraphicsDevice);
        btn = new Button(Content.Load<Texture2D>("Sprites/Button"), new Vector2(150, 150));
    }
    protected override void UnloadContent()
    {
    }
    protected override void Update(GameTime gameTime)
    {
        if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)
            this.Exit();
        MouseState mouse = Mouse.GetState();
        //Debug.WriteLine(mouse);

        if (btn.Clicked == true)
        {
            Debug.WriteLine("Clicked");
            currentState = GameState.Playing;
            btn.Update(mouse);
        }
        base.Update(gameTime);
    }
    protected override void Draw(GameTime gameTime)
    {
        GraphicsDevice.Clear(Color.CornflowerBlue);

        spriteBatch.Begin();
        spriteBatch.Draw(Content.Load<Texture2D>("Sprites/StartBg"), new Rectangle(0, 0, _screenWidth, _screenHeight), Color.White);
        btn.Draw(spriteBatch);
        spriteBatch.End();
        base.Draw(gameTime);
    }
}

Button class

public class Button
{
    public bool Clicked { get; set; }
    private Texture2D _image;
    private Rectangle _rectangle, _mouseRectangle;
    private Vector2 _coordinate;
    private Color _color;
    private bool _down;

    public Button(Texture2D image, Vector2 coordinate)
    {
        _image = image;
        _coordinate = coordinate;
    }
    public void Update(MouseState mouse)
    {
        mouse = Mouse.GetState();
        _rectangle = new Rectangle((int)_coordinate.X, (int)_coordinate.Y, _image.Width, _image.Height);
        _mouseRectangle = new Rectangle(mouse.X, mouse.Y, 1, 1);

        if (_mouseRectangle.Intersects(_rectangle))
        {
            if (_color.A == 255)
                _down = false;
            if (_color.A == 0)
                _down = true;
            if (_down)
            {
                _color.A += 3;
            }
            else
            {
                _color.A -= 3;
            }
            if (mouse.LeftButton == ButtonState.Pressed)
            {
                Clicked = true;
            }
            else if (_color.A < 255)
            {
                _color.A += 3;
                Clicked = false;
            }
        }
    }
    public void Draw(SpriteBatch spriteBatch)
    {
        spriteBatch.Draw(_image, _coordinate, Color.White);
    }
}

Answer 1

Your logic is a bit messed up. In a sentence, your code is: if button is clicked, do update in which you check if it's clicked. This way you will never update your button.

Try this modified version of your Update function:

protected override void Update(GameTime gameTime)
{
    if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)
        this.Exit();
    MouseState mouse = Mouse.GetState();
    //Debug.WriteLine(mouse);

    btn.Update(mouse);
    if (btn.Clicked == true)
    {
        Debug.WriteLine("Clicked");
        currentState = GameState.Playing;
    }
    base.Update(gameTime);
}

This code in a sentence means: do update of button which check if button is clicked, and after that, if button is clicked, wtride "Clicked" in debug and set gameState to Playing.

Edit 1:
Also, I don't see how color is supposed to be related to the clicking. In buttons Update methd, I am worried about this peace of code

        if (mouse.LeftButton == ButtonState.Pressed)
        {
            Clicked = true;
        }
        else if (_color.A < 255)
        {
            _color.A += 3;
            Clicked = false;
        }

I'd rather put something like this:

        if (mouse.LeftButton == ButtonState.Pressed)
        {
            Clicked = true;
        }
        else
        {
            if (_color.A < 255)
                _color.A += 3;
            Clicked = false;
        }

This way it's simpler to put this code in a sentence, and this simplicity makes it work no matter what value _color.A is, but _color.A will also be updated when you need it.