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#region File Description
//-----------------------------------------------------------------------------
// MessageBoxScreen.cs
//
// Microsoft XNA Community Game Platform
// Copyright (C) Microsoft Corporation. All rights reserved.
//-----------------------------------------------------------------------------
#endregion
#region Using Statements
using System;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.Graphics;
#endregion
namespace AIDemos
{
/// <summary>
/// A popup message box screen, used to display "are you sure?"
/// confirmation messages.
/// </summary>
public class MessageBoxScreen : GameScreen
{
#region Fields
string message;
Texture2D gradientTexture;
#endregion
#region Events
public event EventHandler<PlayerIndexEventArgs> Accepted;
public event EventHandler<PlayerIndexEventArgs> Cancelled;
#endregion
#region Initialization
/// <summary>
/// Constructor automatically includes the standard "A=ok, B=cancel"
/// usage text prompt.
/// </summary>
public MessageBoxScreen(string message)
: this(message, true)
{ }
/// <summary>
/// Constructor lets the caller specify whether to include the standard
/// "A=ok, B=cancel" usage text prompt.
/// </summary>
public MessageBoxScreen(string message, bool includeUsageText)
{
const string usageText = "\nA button, Space, Enter = ok" +
"\nB button, Esc = cancel";
if (includeUsageText)
this.message = message + usageText;
else
this.message = message;
IsPopup = true;
TransitionOnTime = TimeSpan.FromSeconds(0.2);
TransitionOffTime = TimeSpan.FromSeconds(0.2);
}
/// <summary>
/// Loads graphics content for this screen. This uses the shared ContentManager
/// provided by the Game class, so the content will remain loaded forever.
/// Whenever a subsequent MessageBoxScreen tries to load this same content,
/// it will just get back another reference to the already loaded data.
/// </summary>
public override void LoadContent()
{
ContentManager content = ScreenManager.Game.Content;
gradientTexture = content.Load<Texture2D>("gradient");
}
#endregion
#region Handle Input
/// <summary>
/// Responds to user input, accepting or cancelling the message box.
/// </summary>
public override void HandleInput(InputState input)
{
PlayerIndex playerIndex;
// We pass in our ControllingPlayer, which may either be null (to
// accept input from any player) or a specific index. If we pass a null
// controlling player, the InputState helper returns to us which player
// actually provided the input. We pass that through to our Accepted and
// Cancelled events, so they can tell which player triggered them.
if (input.IsMenuSelect(ControllingPlayer, out playerIndex))
{
// Raise the accepted event, then exit the message box.
if (Accepted != null)
Accepted(this, new PlayerIndexEventArgs(playerIndex));
ExitScreen();
}
else if (input.IsMenuCancel(ControllingPlayer, out playerIndex))
{
// Raise the cancelled event, then exit the message box.
if (Cancelled != null)
Cancelled(this, new PlayerIndexEventArgs(playerIndex));
ExitScreen();
}
}
#endregion
#region Draw
/// <summary>
/// Draws the message box.
/// </summary>
public override void Draw(GameTime gameTime)
{
SpriteBatch spriteBatch = ScreenManager.SpriteBatch;
SpriteFont font = ScreenManager.Font;
// Darken down any other screens that were drawn beneath the popup.
ScreenManager.FadeBackBufferToBlack(TransitionAlpha * 2 / 3);
// Center the message text in the viewport.
Viewport viewport = ScreenManager.GraphicsDevice.Viewport;
Vector2 viewportSize = new Vector2(viewport.Width, viewport.Height);
Vector2 textSize = font.MeasureString(message);
Vector2 textPosition = (viewportSize - textSize) / 2;
// The background includes a border somewhat larger than the text itself.
const int hPad = 32;
const int vPad = 16;
Rectangle backgroundRectangle = new Rectangle((int)textPosition.X - hPad,
(int)textPosition.Y - vPad,
(int)textSize.X + hPad * 2,
(int)textSize.Y + vPad * 2);
// Fade the popup alpha during transitions.
Color color = new Color(255, 255, 255, TransitionAlpha);
spriteBatch.Begin();
// Draw the background rectangle.
spriteBatch.Draw(gradientTexture, backgroundRectangle, color);
// Draw the message box text.
spriteBatch.DrawString(font, message, textPosition, color);
spriteBatch.End();
}
#endregion
}
} |
