XNA Button

This post is about creating a simple event-based button in XNA. I'll dump the code here. Future self is responsible for understanding it in case he/I don't remember it.

public class Button

{

Texture2D _upTexture, _mouseOverTexture, _mouseDownTexture, _disabledTexture;

int _width, _height, _x, _y;

string _name;

bool _enabled;

Rectangle _drawRectangle;

//States

ButtonStates _state;

KeyboardState _prevKeyState;

MouseState _prevMouseState;

public bool Enabled

{

get

{

return _enabled;

}

set

{

_enabled = value;

}

}

public string Name

{

get

{

return _name; 

}

set

{

_name = value;

}

}

public int Width

{

get

{

return _width;        

}

set

{

_width = value;

UpdateRectangle();

}

}

public int Height

{

get

{

return _height;

}

set

{

_height = value;

UpdateRectangle();

}

}

public int Left

{

get

{

return _x;

}

set

{

_x = value;

UpdateRectangle();

}

}

public int Top

{

get

{

return _y;

}

set

{

_y = value;

UpdateRectangle();

}

}

void UpdateRectangle()

{

_drawRectangle.X = _x;

_drawRectangle.Y = _y;

_drawRectangle.Width = _width;

_drawRectangle.Height = _height;

}

public Button(Texture2D up, Texture2D mouseOver, Texture2D mouseDown, Texture2D disabled)

{

_upTexture = up;

_mouseOverTexture = mouseOver;

_mouseDownTexture = mouseDown;

_disabledTexture = disabled;

_width = _height = 50;

_x = _y = 0;

_enabled = true;

_drawRectangle = new Rectangle();

_state = ButtonStates.Up;

}

public void Update()

{

if (_prevKeyState == null || _prevMouseState == null)

{

_prevMouseState = Mouse.GetState();

_prevKeyState = Keyboard.GetState();

return;

}

KeyboardState currentKeyState = Keyboard.GetState();

MouseState currentMouseState = Mouse.GetState();

if (_enabled)

{

switch (_state)

{

case ButtonStates.Up:

if (_drawRectangle.Contains(currentMouseState.X, currentMouseState.Y))

{

if (currentMouseState.LeftButton == ButtonState.Pressed && _prevMouseState.LeftButton != ButtonState.Pressed)

{

_state = ButtonStates.MouseDown;

}

else

{

_state = ButtonStates.MouseOver;

}

}

break;

case ButtonStates.MouseOver:

if (_drawRectangle.Contains(currentMouseState.X, currentMouseState.Y))

{

if (currentMouseState.LeftButton == ButtonState.Pressed && _prevMouseState.LeftButton != ButtonState.Pressed)

{

_state = ButtonStates.MouseDown;

}

}

else

{

_state = ButtonStates.Up;

}

break;

case ButtonStates.MouseDown:

if (_drawRectangle.Contains(currentMouseState.X, currentMouseState.Y))

{

if (currentMouseState.LeftButton != ButtonState.Pressed && _prevMouseState.LeftButton == ButtonState.Pressed)

{

_state = ButtonStates.Up;

//Fire Click event

if (OnClick != null)

{

OnClick(this);

}

}

}

else

{

if (currentMouseState.LeftButton != ButtonState.Pressed && _prevMouseState.LeftButton == ButtonState.Pressed)

{

//Release outside

_state = ButtonStates.Up;                                

}

}

break;

default:

break;

}

}           

_prevKeyState = currentKeyState;

_prevMouseState = currentMouseState;

}

public void Draw(SpriteBatch spriteBatch)

{

if (_enabled)

{

switch (_state)

{

case ButtonStates.Up:

if (_upTexture != null)

{

spriteBatch.Draw(_upTexture, _drawRectangle, Color.White);

}

break;

case ButtonStates.MouseOver:

if (_mouseOverTexture != null)

{

spriteBatch.Draw(_mouseOverTexture, _drawRectangle, Color.White);

}

break;

case ButtonStates.MouseDown:

if (_mouseDownTexture != null)

{

spriteBatch.Draw(_mouseDownTexture, _drawRectangle, Color.White);

}

break;

default:

break;

}

}

else

{

if (_disabledTexture != null)

{

spriteBatch.Draw(_disabledTexture, _drawRectangle, Color.White);                   

}

}            

}

//Events

public delegate void Click(Button sender);

public event Click OnClick;

public enum ButtonStates

{

Up,

MouseOver,

MouseDown

}

}

Thats it! Use OnClick event in the game to tap the click event, call button.Update() in the update logic of the game code.