XNA之RPG游戏开发教程之六

本节的任务有两点：1、创建一个新控件，实现角色的选择；具体操作要求是按左键，呈现上一个角色信息，按右键呈现下一个角色信息；2、创建一个角色选择页面，将新控件添加进去

首先开始第一个任务，前面已经创建了控件基类Control类和控件管理类ControlManager类，新的控件要继承基类，并在页面实例化后要添加进管理类中便于操作管理。新控件LeftRightSelector，一个向左向右可选择控件的代码实现如下

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using Microsoft.Xna.Framework;

using Microsoft.Xna.Framework.Graphics;

using Microsoft.Xna.Framework.Input;

namespace XRpgLibrary.Controls

{

public class LeftRightSelector : Control

 {

 #region Event Region

public event EventHandler SelectionChanged;//控件选择更改事件

 #endregion

 #region Field Region

List<string> items = new List<string>();//控件中呈现字符串集合

Texture2D leftTexture;//表示向左，向右，尽头终止的图片

Texture2D rightTexture;

Texture2D stopTexture;

Color selectedColor = Color.Red;//被选字符串呈现红色

int maxItemWidth;//字符串项的最大宽度

int selectedItem;//被选择的项索引

 #endregion

 #region Property Region

public Color SelectedColor

 {

  get { return selectedColor; }

  set { selectedColor = value; }

 }
public int SelectedIndex

 {

  get { return selectedItem; }

  set { selectedItem = (int)MathHelper.Clamp(value, 0f, items.Count); }

 }

public string SelectedItem

 {

  get { return Items[selectedItem]; }

 }

public List<string> Items

 {

  get { return items; }

 }

 #endregion

 #region Constructor Region

public LeftRightSelector(Texture2D leftArrow, Texture2D rightArrow, Texture2D stop)

 {

 leftTexture = leftArrow;

 rightTexture = rightArrow;

 stopTexture = stop;

 TabStop = true;

 Color = Color.White;

 }

 #endregion

 #region Method Region为字符串序列和字符串最大宽度赋值

public void SetItems(string[] items, int maxWidth)

 {

 this.items.Clear();

 foreach (string s in items)

 this.items.Add(s);

 maxItemWidth = maxWidth;

 }
//事件触发函数

protected void OnSelectionChanged()

 {

  if (SelectionChanged != null)

 {

   SelectionChanged(this, null);

 }

 }

 #endregion

 #region Abstract Method Region

public override void Update(GameTime gameTime)

 {

 }

public override void Draw(SpriteBatch spriteBatch)

 {

  Vector2 drawTo = position;

  if (selectedItem != 0)

   spriteBatch.Draw(leftTexture, drawTo, Color.White);

  else

   spriteBatch.Draw(stopTexture, drawTo, Color.White);

  drawTo.X += leftTexture.Width + 5f;
  float itemWidth = spriteFont.MeasureString(items[selectedItem]).X;

  float offset = (maxItemWidth - itemWidth) / 2;

  drawTo.X += offset;

  if (hasFocus)

    spriteBatch.DrawString(spriteFont, items[selectedItem], drawTo, selectedColor);

  else

    spriteBatch.DrawString(spriteFont, items[selectedItem], drawTo, Color);

  drawTo.X += -1 * offset + maxItemWidth + 5f;

  if (selectedItem != items.Count - 1)

    spriteBatch.Draw(rightTexture, drawTo, Color.White);

  else

    spriteBatch.Draw(stopTexture, drawTo, Color.White);

 }

public override void HandleInput(PlayerIndex playerIndex)

 {

  if (items.Count == 0)

   return;

  if (InputHandler.ButtonReleased(Buttons.LeftThumbstickLeft, playerIndex) ||

   InputHandler.ButtonReleased(Buttons.DPadLeft, playerIndex) ||

   InputHandler.KeyReleased(Keys.Left))

 {

 selectedItem--;

if (selectedItem < 0)

 selectedItem = 0;

 OnSelectionChanged();//触发事件

 }

if (InputHandler.ButtonReleased(Buttons.LeftThumbstickRight, playerIndex) ||

InputHandler.ButtonReleased(Buttons.DPadRight, playerIndex) ||

InputHandler.KeyReleased(Keys.Right))

 {

 selectedItem++;

if (selectedItem >= items.Count)

 selectedItem = items.Count - 1;

 OnSelectionChanged();

 }

 }

 #endregion

 }

}

接着就是添加一个新的游戏页面，用来选取角色信息，具体代码如下

using System;

using System.Collections.Generic;

using System.Linq;using System.Text;

using Microsoft.Xna.Framework;

using Microsoft.Xna.Framework.Graphics;

using Microsoft.Xna.Framework.Input;

using XRpgLibrary;

using XRpgLibrary.Controls;

namespace EyesOfTheDragon.GameScreens

{

public class CharacterGeneratorScreen : BaseGameState

 {

 #region Field Region

 LeftRightSelector genderSelector;//关于角色性别的selector控件

 LeftRightSelector classSelector;//关于角色类型的selector控件

 PictureBox backgroundImage;//游戏背景图片框

string[] genderItems = { "Male", "Female" };//用于初始化性别selector控件的字符串集

string[] classItems = { "Fighter", "Wizard", "Rogue", "Priest" };

 #endregion

 #region Property Region

 #endregion

 #region Constructor Region

public CharacterGeneratorScreen(Game game, GameStateManager stateManager)

 : base(game, stateManager)

 {

 }

 #endregion

 #region XNA Method Region

public override void Initialize()

 {

base.Initialize();

 }

protected override void LoadContent()

 {

 base.LoadContent();

 CreateControls();

 }

public override void Update(GameTime gameTime)

 {

 ControlManager.Update(gameTime, PlayerIndex.One);//对ControlManager进行更新，在其中会触发对页面上所有控件的更新

 base.Update(gameTime);

 }

public override void Draw(GameTime gameTime)

 {

 GameRef.SpriteBatch.Begin();

 base.Draw(gameTime);

 ControlManager.Draw(GameRef.SpriteBatch);//ControlManager的绘制，在其中可以对页面上所有控件进行绘制

 GameRef.SpriteBatch.End();

 }

 #endregion

 #region Method Region
private void CreateControls()

 {

Texture2D leftTexture = Game.Content.Load<Texture2D>(@"GUI\leftarrowUp");

Texture2D rightTexture = Game.Content.Load<Texture2D>(@"GUI\rightarrowUp");

Texture2D stopTexture = Game.Content.Load<Texture2D>(@"GUI\StopBar");

 backgroundImage = new PictureBox(

 Game.Content.Load<Texture2D>(@"Backgrounds\titlescreen"),

 GameRef.ScreenRectangle);

 ControlManager.Add(backgroundImage);//实例化背景控件，并加入到控件管理类中

 Label label1 = new Label();

 label1.Text = "Who will search for the Eyes of the Dragon?";

 label1.Size = label1.SpriteFont.MeasureString(label1.Text);

 label1.Position = new Vector2((GameRef.Window.ClientBounds.Width - label1.Size.X) /

2, 150);

 ControlManager.Add(label1);//实例化标题label，并加入到控件管理类中

 genderSelector = new LeftRightSelector(leftTexture, rightTexture, stopTexture);

 genderSelector.SetItems(genderItems, 125);

 genderSelector.Position = new Vector2(label1.Position.X, 200);

 ControlManager.Add(genderSelector);//实例化性别selector，加入管理类

 classSelector = new LeftRightSelector(leftTexture, rightTexture, stopTexture);

 classSelector.SetItems(classItems, 125);

 classSelector.Position = new Vector2(label1.Position.X, 250);

 ControlManager.Add(classSelector);//实例化类型selector，加入管理类

LinkLabel linkLabel1 = new LinkLabel();

 linkLabel1.Text = "Accept this character.";

 linkLabel1.Position = new Vector2(label1.Position.X, 300);

 linkLabel1.Selected += new EventHandler(linkLabel1_Selected);

 ControlManager.Add(linkLabel1);//实例化接受LinkLabel对象，加入管理类

 ControlManager.NextControl();//执行NextControl，使得当前呈现选项为被选中状态

 }

void linkLabel1_Selected(object sender, EventArgs e)

 {

 InputHandler.Flush();

 StateManager.PopState();

 StateManager.PushState(GameRef.GamePlayScreen);//呈现游戏页面

 }

 #endregion

 }

}

接下来就是讲新的角色选择页面添加到Game1类中，代码如下

public CharacterGeneratorScreen CharacterGeneratorScreen;

public Game1()

{

 graphics = new GraphicsDeviceManager(this);

 graphics.PreferredBackBufferWidth = screenWidth;

 graphics.PreferredBackBufferHeight = screenHeight;

 ScreenRectangle = new Rectangle(

 0,

 0,

 screenWidth,

 screenHeight);

 Content.RootDirectory = "Content";

 Components.Add(new InputHandler(this)); 
 stateManager = new GameStateManager(this);

 Components.Add(stateManager);

 TitleScreen = new TitleScreen(this, stateManager);

 StartMenuScreen = new StartMenuScreen(this, stateManager);

 GamePlayScreen = new GamePlayScreen(this, stateManager);

 CharacterGeneratorScreen = new CharacterGeneratorScreen(this, stateManager);//添加新的页面

 stateManager.ChangeState(TitleScreen);

}

同时在StartMenuScreen页面中修改menuItem_Selected方法，使得选择startgame选项时候，跳转到新建的角色选择页面

private void menuItem_Selected(object sender, EventArgs e)

{

if (sender == startGame)

 {

 StateManager.PushState(GameRef.CharacterGeneratorScreen);

 }

if (sender == loadGame)

 {

 StateManager.PushState(GameRef.GamePlayScreen);

 }

if (sender == exitGame)

 {

 GameRef.Exit();

 }

}

OK,本节任务结束