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Terminal.Gui/Terminal.Gui/Views/Button.cs
2020-10-20 21:11:11 +01:00

242 lines
7.2 KiB
C#

//
// Button.cs: Button control
//
// Authors:
// Miguel de Icaza (miguel@gnome.org)
//
using System;
using NStack;
namespace Terminal.Gui {
/// <summary>
/// Button is a <see cref="View"/> that provides an item that invokes an <see cref="Action"/> when activated by the user.
/// </summary>
/// <remarks>
/// <para>
/// Provides a button showing text invokes an <see cref="Action"/> when clicked on with a mouse
/// or when the user presses SPACE, ENTER, or hotkey. The hotkey is the first letter or digit following the first underscore ('_')
/// in the button text.
/// </para>
/// <para>
/// Use <see cref="View.HotKeySpecifier"/> to change the hotkey specifier from the default of ('_').
/// </para>
/// <para>
/// If no hotkey specifier is found, the first uppercase letter encountered will be used as the hotkey.
/// </para>
/// <para>
/// When the button is configured as the default (<see cref="IsDefault"/>) and the user presses
/// the ENTER key, if no other <see cref="View"/> processes the <see cref="KeyEvent"/>, the <see cref="Button"/>'s
/// <see cref="Action"/> will be invoked.
/// </para>
/// </remarks>
public class Button : View {
ustring text;
bool is_default;
/// <summary>
/// Initializes a new instance of <see cref="Button"/> using <see cref="LayoutStyle.Computed"/> layout.
/// </summary>
/// <remarks>
/// The width of the <see cref="Button"/> is computed based on the
/// text length. The height will always be 1.
/// </remarks>
public Button () : this (text: string.Empty, is_default: false) { }
/// <summary>
/// Initializes a new instance of <see cref="Button"/> using <see cref="LayoutStyle.Computed"/> layout.
/// </summary>
/// <remarks>
/// The width of the <see cref="Button"/> is computed based on the
/// text length. The height will always be 1.
/// </remarks>
/// <param name="text">The button's text</param>
/// <param name="is_default">
/// If <c>true</c>, a special decoration is used, and the user pressing the enter key
/// in a <see cref="Dialog"/> will implicitly activate this button.
/// </param>
public Button (ustring text, bool is_default = false) : base ()
{
Init (text, is_default);
}
/// <summary>
/// Initializes a new instance of <see cref="Button"/> using <see cref="LayoutStyle.Absolute"/> layout, based on the given text
/// </summary>
/// <remarks>
/// The width of the <see cref="Button"/> is computed based on the
/// text length. The height will always be 1.
/// </remarks>
/// <param name="x">X position where the button will be shown.</param>
/// <param name="y">Y position where the button will be shown.</param>
/// <param name="text">The button's text</param>
public Button (int x, int y, ustring text) : this (x, y, text, false) { }
/// <summary>
/// Initializes a new instance of <see cref="Button"/> using <see cref="LayoutStyle.Absolute"/> layout, based on the given text.
/// </summary>
/// <remarks>
/// The width of the <see cref="Button"/> is computed based on the
/// text length. The height will always be 1.
/// </remarks>
/// <param name="x">X position where the button will be shown.</param>
/// <param name="y">Y position where the button will be shown.</param>
/// <param name="text">The button's text</param>
/// <param name="is_default">
/// If <c>true</c>, a special decoration is used, and the user pressing the enter key
/// in a <see cref="Dialog"/> will implicitly activate this button.
/// </param>
public Button (int x, int y, ustring text, bool is_default)
: base (new Rect (x, y, text.RuneCount + 4 + (is_default ? 2 : 0), 1))
{
Init (text, is_default);
}
Rune _leftBracket;
Rune _rightBracket;
Rune _leftDefault;
Rune _rightDefault;
void Init (ustring text, bool is_default)
{
HotKeySpecifier = new Rune ('_');
_leftBracket = new Rune (Driver != null ? Driver.LeftBracket : '[');
_rightBracket = new Rune (Driver != null ? Driver.RightBracket : ']');
_leftDefault = new Rune (Driver != null ? Driver.LeftDefaultIndicator : '<');
_rightDefault = new Rune (Driver != null ? Driver.RightDefaultIndicator : '>');
CanFocus = true;
this.IsDefault = is_default;
Text = text ?? string.Empty;
}
/// <summary>
/// The text displayed by this <see cref="Button"/>.
/// </summary>
public new ustring Text {
get {
return text;
}
set {
text = value;
Update ();
}
}
/// <summary>
/// Gets or sets whether the <see cref="Button"/> is the default action to activate in a dialog.
/// </summary>
/// <value><c>true</c> if is default; otherwise, <c>false</c>.</value>
public bool IsDefault {
get => is_default;
set {
is_default = value;
Update ();
}
}
internal void Update ()
{
if (IsDefault)
base.Text = ustring.Make (_leftBracket) + ustring.Make (_leftDefault) + " " + text + " " + ustring.Make (_rightDefault) + ustring.Make (_rightBracket);
else
base.Text = ustring.Make (_leftBracket) + " " + text + " " + ustring.Make (_rightBracket);
int w = base.Text.RuneCount - (base.Text.Contains (HotKeySpecifier) ? 1 : 0);
if (Width is Dim.DimCombine) {
// It's a Dim.DimCombine and so can't be assigned. Let it have it's own anchor.
w = Width.Anchor (w);
}
Height = 1;
Frame = new Rect (Frame.Location, new Size (w, 1));
SetNeedsDisplay ();
}
bool CheckKey (KeyEvent key)
{
if (key.Key == (Key.AltMask | HotKey)) {
SetFocus ();
Clicked?.Invoke ();
return true;
}
return false;
}
///<inheritdoc/>
public override bool ProcessHotKey (KeyEvent kb)
{
if (kb.IsAlt)
return CheckKey (kb);
return false;
}
///<inheritdoc/>
public override bool ProcessColdKey (KeyEvent kb)
{
if (IsDefault && kb.KeyValue == '\n') {
Clicked?.Invoke ();
return true;
}
return CheckKey (kb);
}
///<inheritdoc/>
public override bool ProcessKey (KeyEvent kb)
{
var c = kb.KeyValue;
if (c == '\n' || c == ' ' || kb.Key == HotKey) {
Clicked?.Invoke ();
return true;
}
return base.ProcessKey (kb);
}
/// <summary>
/// Clicked <see cref="Action"/>, raised when the user clicks the primary mouse button within the Bounds of this <see cref="View"/>
/// or if the user presses the action key while this view is focused. (TODO: IsDefault)
/// </summary>
/// <remarks>
/// Client code can hook up to this event, it is
/// raised when the button is activated either with
/// the mouse or the keyboard.
/// </remarks>
public event Action Clicked;
///<inheritdoc/>
public override bool MouseEvent (MouseEvent me)
{
if (me.Flags == MouseFlags.Button1Clicked || me.Flags == MouseFlags.Button1DoubleClicked ||
me.Flags == MouseFlags.Button1TripleClicked) {
if (CanFocus) {
if (!HasFocus) {
SetFocus ();
SetNeedsDisplay ();
}
Clicked?.Invoke ();
}
return true;
}
return false;
}
///<inheritdoc/>
public override void PositionCursor ()
{
if (HotKey == Key.Unknown) {
for (int i = 0; i < base.Text.RuneCount; i++) {
if (base.Text [i] == text [0]) {
Move (i, 0);
return;
}
}
}
base.PositionCursor ();
}
}
}