w4d.widget.wrapper source code

1 // Written in the D programming language.
2 /++
3  + Authors: KanzakiKino
4  + Copyright: KanzakiKino 2018
5  + License: LGPL-3.0
6 ++/
7 module w4d.widget.wrapper;
8 import w4d.layout.placer.lineup,
9        w4d.layout.fill,
10        w4d.widget.base,
11        w4d.exception;
12 import std.conv;
13 
14 /// A widget that wraps other wraps.
15 class WrapperWidget : Widget
16 {
17     protected Widget _child;
18 
19     ///
20     override @property Widget[] children ()
21     {
22         return _child? [_child]: [];
23     }
24     /// Child widget that is wrapped.
25     @property T child (T = Widget) ()
26     {
27         return _child.to!T;
28     }
29 
30     ///
31     this ()
32     {
33         super();
34         setLayout!( FillLayout, VerticalLineupPlacer );
35 
36         _child = null;
37     }
38 
39     /// Changes the child widget.
40     Widget setChild ( Widget child )
41     {
42         enforce( child, "Null is not a valid child." );
43         _child = child;
44         requestLayout();
45         return child;
46     }
47     /// Removes the child widget.
48     void removeChild ()
49     {
50         _context.forget( _child );
51         _child = null;
52         requestLayout();
53     }
54 
55     protected static template DisableModifyChild ()
56     {
57         import w4d.widget.base,
58                w4d.exception;
59 
60         enum DisableModifyChild_ErrorMes = "Modifying a child is not allowed.";
61 
62         override Widget setChild ( Widget child )
63         {
64             throw new W4dException( DisableModifyChild_ErrorMes );
65         }
66         override void removeChild ()
67         {
68             throw new W4dException( DisableModifyChild_ErrorMes );
69         }
70     }
71 
72     ///
73     override @property bool trackable () { return false; }
74     ///
75     override @property bool focusable () { return false; }
76 }