啊,文本输入-我最近有这方面的经验。
问题
通常,Keyboard.GetKeyboardState()
获取文本输入很糟糕,这有很多原因,其中一些是:
- 你必须编写一个巨大的开关来检测按下了什么键
- 您必须手动检测是否大写字母(Shift 或 CapsLock)
- 您必须破译那些类似
OemPeriod
密钥(如在测试中)以查看它们的实际位置,并将它们映射到特定值。
- 无法检测/使用键盘布局或键盘语言
- 如果按键被按住,您必须实现自己的计时重复机制
问题的第二部分是检测您的哪个文本框(或一般的 UI 控件)当前正在接收此输入,因为您不希望所有框在您键入时都接收文本。
第三,您需要在指定的范围内绘制 TextBox,并且您可能还需要绘制插入符号(闪烁的垂直位置指示器)、当前选择(如果您想实现它)、表示框,以及突出显示(使用鼠标)或选定(具有焦点)状态的纹理。
第四,您必须手动实现复制粘贴功能。
速记
您可能不需要所有这些功能,因为我不需要它们。您只需要简单的输入,并检测诸如 enter 或 tab 之类的键,以及鼠标单击。也许也粘贴。
解决方案
问题是(至少当我们谈论 Windows,而不是 X-Box 或 WP7 时),操作系统已经拥有必要的机制来实现你从键盘上需要的一切:
- 根据当前的键盘布局和语言给出字符
- 自动处理重复输入(在按键被按住的情况下)
- 自动大写并提供特殊字符
我用于获取键盘输入的解决方案,我已经复制了这个 Gamedev.net 论坛帖子。它是下面的代码,您只需将其复制粘贴到一个 .cs 文件中,您将永远不必再次打开该文件。
它用于从您的键盘接收本地化输入,您需要做的就是在您的Game.Initialize()
覆盖方法中初始化它(通过使用 Game.Window),并连接到事件以在您想要的任何地方接收输入。
您需要将PresentationCore
(PresentationCore.dll) 添加到您的引用中才能使用此代码(System.Windows.Input
命名空间需要)。这适用于 .NET 4.0 和 .NET 4.0 客户端配置文件。
事件输入
using System;
using System.Runtime.InteropServices;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Input;
using System.Text;
using System.Windows.Input;
namespace EventInput
{
public class KeyboardLayout
{
const uint KLF_ACTIVATE = 1; //activate the layout
const int KL_NAMELENGTH = 9; // length of the keyboard buffer
const string LANG_EN_US = "00000409";
const string LANG_HE_IL = "0001101A";
[DllImport("user32.dll")]
private static extern long LoadKeyboardLayout(
string pwszKLID, // input locale identifier
uint Flags // input locale identifier options
);
[DllImport("user32.dll")]
private static extern long GetKeyboardLayoutName(
System.Text.StringBuilder pwszKLID //[out] string that receives the name of the locale identifier
);
public static string getName()
{
System.Text.StringBuilder name = new System.Text.StringBuilder(KL_NAMELENGTH);
GetKeyboardLayoutName(name);
return name.ToString();
}
}
public class CharacterEventArgs : EventArgs
{
private readonly char character;
private readonly int lParam;
public CharacterEventArgs(char character, int lParam)
{
this.character = character;
this.lParam = lParam;
}
public char Character
{
get { return character; }
}
public int Param
{
get { return lParam; }
}
public int RepeatCount
{
get { return lParam & 0xffff; }
}
public bool ExtendedKey
{
get { return (lParam & (1 << 24)) > 0; }
}
public bool AltPressed
{
get { return (lParam & (1 << 29)) > 0; }
}
public bool PreviousState
{
get { return (lParam & (1 << 30)) > 0; }
}
public bool TransitionState
{
get { return (lParam & (1 << 31)) > 0; }
}
}
public class KeyEventArgs : EventArgs
{
private Keys keyCode;
public KeyEventArgs(Keys keyCode)
{
this.keyCode = keyCode;
}
public Keys KeyCode
{
get { return keyCode; }
}
}
public delegate void CharEnteredHandler(object sender, CharacterEventArgs e);
public delegate void KeyEventHandler(object sender, KeyEventArgs e);
public static class EventInput
{
/// <summary>
/// Event raised when a character has been entered.
/// </summary>
public static event CharEnteredHandler CharEntered;
/// <summary>
/// Event raised when a key has been pressed down. May fire multiple times due to keyboard repeat.
/// </summary>
public static event KeyEventHandler KeyDown;
/// <summary>
/// Event raised when a key has been released.
/// </summary>
public static event KeyEventHandler KeyUp;
delegate IntPtr WndProc(IntPtr hWnd, uint msg, IntPtr wParam, IntPtr lParam);
static bool initialized;
static IntPtr prevWndProc;
static WndProc hookProcDelegate;
static IntPtr hIMC;
//various Win32 constants that we need
const int GWL_WNDPROC = -4;
const int WM_KEYDOWN = 0x100;
const int WM_KEYUP = 0x101;
const int WM_CHAR = 0x102;
const int WM_IME_SETCONTEXT = 0x0281;
const int WM_INPUTLANGCHANGE = 0x51;
const int WM_GETDLGCODE = 0x87;
const int WM_IME_COMPOSITION = 0x10f;
const int DLGC_WANTALLKEYS = 4;
//Win32 functions that we're using
[DllImport("Imm32.dll", CharSet = CharSet.Unicode)]
static extern IntPtr ImmGetContext(IntPtr hWnd);
[DllImport("Imm32.dll", CharSet = CharSet.Unicode)]
static extern IntPtr ImmAssociateContext(IntPtr hWnd, IntPtr hIMC);
[DllImport("user32.dll", CharSet = CharSet.Unicode)]
static extern IntPtr CallWindowProc(IntPtr lpPrevWndFunc, IntPtr hWnd, uint Msg, IntPtr wParam, IntPtr lParam);
[DllImport("user32.dll", CharSet = CharSet.Unicode)]
static extern int SetWindowLong(IntPtr hWnd, int nIndex, int dwNewLong);
/// <summary>
/// Initialize the TextInput with the given GameWindow.
/// </summary>
/// <param name="window">The XNA window to which text input should be linked.</param>
public static void Initialize(GameWindow window)
{
if (initialized)
throw new InvalidOperationException("TextInput.Initialize can only be called once!");
hookProcDelegate = new WndProc(HookProc);
prevWndProc = (IntPtr)SetWindowLong(window.Handle, GWL_WNDPROC,
(int)Marshal.GetFunctionPointerForDelegate(hookProcDelegate));
hIMC = ImmGetContext(window.Handle);
initialized = true;
}
static IntPtr HookProc(IntPtr hWnd, uint msg, IntPtr wParam, IntPtr lParam)
{
IntPtr returnCode = CallWindowProc(prevWndProc, hWnd, msg, wParam, lParam);
switch (msg)
{
case WM_GETDLGCODE:
returnCode = (IntPtr)(returnCode.ToInt32() | DLGC_WANTALLKEYS);
break;
case WM_KEYDOWN:
if (KeyDown != null)
KeyDown(null, new KeyEventArgs((Keys)wParam));
break;
case WM_KEYUP:
if (KeyUp != null)
KeyUp(null, new KeyEventArgs((Keys)wParam));
break;
case WM_CHAR:
if (CharEntered != null)
CharEntered(null, new CharacterEventArgs((char)wParam, lParam.ToInt32()));
break;
case WM_IME_SETCONTEXT:
if (wParam.ToInt32() == 1)
ImmAssociateContext(hWnd, hIMC);
break;
case WM_INPUTLANGCHANGE:
ImmAssociateContext(hWnd, hIMC);
returnCode = (IntPtr)1;
break;
}
return returnCode;
}
}
}
现在您已经可以按原样使用它(通过订阅EventInput.CharEntered
事件),并使用逻辑来检测将输入发送到何处。
KeyboardDispatcher, IKeyboardSubscriber
我所做的是创建一个类KeyboardDispatcher
,它通过具有类型的属性来处理键盘输入的分派,IKeyboardSubscriber
它将接收到的输入发送到该属性。想法是将此属性设置为要接收输入的 UI 控件。
定义如下:
public interface IKeyboardSubscriber
{
void RecieveTextInput(char inputChar);
void RecieveTextInput(string text);
void RecieveCommandInput(char command);
void RecieveSpecialInput(Keys key);
bool Selected { get; set; } //or Focused
}
public class KeyboardDispatcher
{
public KeyboardDispatcher(GameWindow window)
{
EventInput.EventInput.Initialize(window);
EventInput.EventInput.CharEntered += new EventInput.CharEnteredHandler(EventInput_CharEntered);
EventInput.EventInput.KeyDown += new EventInput.KeyEventHandler(EventInput_KeyDown);
}
void EventInput_KeyDown(object sender, EventInput.KeyEventArgs e)
{
if (_subscriber == null)
return;
_subscriber.RecieveSpecialInput(e.KeyCode);
}
void EventInput_CharEntered(object sender, EventInput.CharacterEventArgs e)
{
if (_subscriber == null)
return;
if (char.IsControl(e.Character))
{
//ctrl-v
if (e.Character == 0x16)
{
//XNA runs in Multiple Thread Apartment state, which cannot recieve clipboard
Thread thread = new Thread(PasteThread);
thread.SetApartmentState(ApartmentState.STA);
thread.Start();
thread.Join();
_subscriber.RecieveTextInput(_pasteResult);
}
else
{
_subscriber.RecieveCommandInput(e.Character);
}
}
else
{
_subscriber.RecieveTextInput(e.Character);
}
}
IKeyboardSubscriber _subscriber;
public IKeyboardSubscriber Subscriber
{
get { return _subscriber; }
set
{
if (_subscriber != null)
_subscriber.Selected = false;
_subscriber = value;
if(value!=null)
value.Selected = true;
}
}
//Thread has to be in Single Thread Apartment state in order to receive clipboard
string _pasteResult = "";
[STAThread]
void PasteThread()
{
if (Clipboard.ContainsText())
{
_pasteResult = Clipboard.GetText();
}
else
{
_pasteResult = "";
}
}
}
用法相当简单,实例化KeyboardDispatcher
,即在Game.Initialize()
其中保留对它的引用(这样您就可以在选定的 [focused] 控件之间切换),并将使用该接口的类传递给它IKeyboardSubscriber
,例如您的TextBox
.
文本框
接下来是您的实际控制。现在我最初编写了一个相当复杂的盒子,它使用渲染目标将文本渲染到纹理,这样我就可以移动它(如果文本比盒子大),但是在经历了很多痛苦之后,我放弃了它并做了一个非常简单的版本。随意改进它!
public delegate void TextBoxEvent(TextBox sender);
public class TextBox : IKeyboardSubscriber
{
Texture2D _textBoxTexture;
Texture2D _caretTexture;
SpriteFont _font;
public int X { get; set; }
public int Y { get; set; }
public int Width { get; set; }
public int Height { get; private set; }
public bool Highlighted { get; set; }
public bool PasswordBox { get; set; }
public event TextBoxEvent Clicked;
string _text = "";
public String Text
{
get
{
return _text;
}
set
{
_text = value;
if (_text == null)
_text = "";
if (_text != "")
{
//if you attempt to display a character that is not in your font
//you will get an exception, so we filter the characters
//remove the filtering if you're using a default character in your spritefont
String filtered = "";
foreach (char c in value)
{
if (_font.Characters.Contains(c))
filtered += c;
}
_text = filtered;
while (_font.MeasureString(_text).X > Width)
{
//to ensure that text cannot be larger than the box
_text = _text.Substring(0, _text.Length - 1);
}
}
}
}
public TextBox(Texture2D textBoxTexture, Texture2D caretTexture, SpriteFont font)
{
_textBoxTexture = textBoxTexture;
_caretTexture = caretTexture;
_font = font;
_previousMouse = Mouse.GetState();
}
MouseState _previousMouse;
public void Update(GameTime gameTime)
{
MouseState mouse = Mouse.GetState();
Point mousePoint = new Point(mouse.X, mouse.Y);
Rectangle position = new Rectangle(X, Y, Width, Height);
if (position.Contains(mousePoint))
{
Highlighted = true;
if (_previousMouse.LeftButton == ButtonState.Released && mouse.LeftButton == ButtonState.Pressed)
{
if (Clicked != null)
Clicked(this);
}
}
else
{
Highlighted = false;
}
}
public void Draw(SpriteBatch spriteBatch, GameTime gameTime)
{
bool caretVisible = true;
if ((gameTime.TotalGameTime.TotalMilliseconds % 1000) < 500)
caretVisible = false;
else
caretVisible = true;
String toDraw = Text;
if (PasswordBox)
{
toDraw = "";
for (int i = 0; i < Text.Length; i++)
toDraw += (char) 0x2022; //bullet character (make sure you include it in the font!!!!)
}
//my texture was split vertically in 2 parts, upper was unhighlighted, lower was highlighted version of the box
spriteBatch.Draw(_textBoxTexture, new Rectangle(X, Y, Width, Height), new Rectangle(0, Highlighted ? (_textBoxTexture.Height / 2) : 0, _textBoxTexture.Width, _textBoxTexture.Height / 2), Color.White);
Vector2 size = _font.MeasureString(toDraw);
if (caretVisible && Selected)
spriteBatch.Draw(_caretTexture, new Vector2(X + (int)size.X + 2, Y + 2), Color.White); //my caret texture was a simple vertical line, 4 pixels smaller than font size.Y
//shadow first, then the actual text
spriteBatch.DrawString(_font, toDraw, new Vector2(X, Y) + Vector2.One, Color.Black);
spriteBatch.DrawString(_font, toDraw, new Vector2(X, Y), Color.White);
}
public void RecieveTextInput(char inputChar)
{
Text = Text + inputChar;
}
public void RecieveTextInput(string text)
{
Text = Text + text;
}
public void RecieveCommandInput(char command)
{
switch (command)
{
case '\b': //backspace
if (Text.Length > 0)
Text = Text.Substring(0, Text.Length - 1);
break;
case '\r': //return
if (OnEnterPressed != null)
OnEnterPressed(this);
break;
case '\t': //tab
if (OnTabPressed != null)
OnTabPressed(this);
break;
default:
break;
}
}
public void RecieveSpecialInput(Keys key)
{
}
public event TextBoxEvent OnEnterPressed;
public event TextBoxEvent OnTabPressed;
public bool Selected
{
get;
set;
}
}
当您实例化 aTextBox
时,不要忘记在实例上设置X
、Y
和Width
(!!!) 值(Height
由字体自动设置)。
我用于盒子的纹理是
(未突出显示有渐变,在黑色背景上看起来不错:))
要显示框调用.Draw()
实例上的方法(在您的Game.Draw()
方法中),并且 spritebatch 已经启动(SpriteBatch.Begin()
调用!!!)。对于您显示的每个框,如果您希望它接收鼠标输入,您应该调用.Update()
方法。
当您希望特定实例接收键盘输入时,请使用您的KeyboardDispatcher
实例订阅它,例如:
_keyboardDispatcher.Subscriber = _usernameTextBox;
您可以使用文本框上的Click
,Tab
和Enter
事件来切换订阅者(我建议您这样做,因为当您可以通过标签浏览它并单击以选择时,它会给 UI 带来非常好的感觉)。
尚未解决的问题
Ofc,我谈到了一些我没有实现的功能,例如如果文本比框宽,框能够平移文本,移动插入符号的能力(插入文本,而不仅仅是追加),选择和复制文本等。
这些问题你可以通过轻微到中等的努力来解决,我敢肯定,但在你这样做之前,问问自己:
我真的需要吗?