docs/doxygen/overviews/dialog.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        dialog.h
   3 // Purpose:     topic overview
   4 // Author:      wxWidgets team
   5 // Licence:     wxWindows licence
   6 /////////////////////////////////////////////////////////////////////////////
   7
   8 /**
   9
  10 @page overview_dialog wxDialog Overview
  11
  12 @tableofcontents
  13
  14 Classes: wxDialog, wxDialogLayoutAdapter
  15
  16 A dialog box is similar to a panel, in that it is a window which can be used
  17 for placing controls, with the following exceptions:
  18
  19 @li A surrounding frame is implicitly created.
  20 @li Extra functionality is automatically given to the dialog box, such as
  21     tabbing between items (currently Windows only).
  22 @li If the dialog box is @e modal, the calling program is blocked until the
  23     dialog box is dismissed.
  24
  25 For a set of dialog convenience functions, including file selection, see
  26 @ref group_funcmacro_dialog.
  27
  28 See also wxTopLevelWindow and wxWindow for inherited member functions.
  29 Validation of data in controls is covered in @ref overview_validator.
  30
  31
  32
  33 @section overview_dialog_autoscrolling Automatic Scrolled Dialogs
  34
  35 As an ever greater variety of mobile hardware comes to market, it becomes more
  36 imperative for wxWidgets applications to adapt to these platforms without
  37 putting too much burden on the programmer. One area where wxWidgets can help is
  38 in adapting dialogs for the lower resolution screens that inevitably accompany
  39 a smaller form factor. wxDialog therefore supplies a global
  40 wxDialogLayoutAdapter class that implements automatic scrolling adaptation for
  41 most sizer-based custom dialogs.
  42
  43 Many applications should therefore be able to adapt to small displays with
  44 little or no work, as far as dialogs are concerned. By default this adaptation
  45 is off. To switch scrolling adaptation on globally in your application, call
  46 the static function wxDialog::EnableLayoutAdaptation passing @true. You can
  47 also adjust adaptation on a per-dialog basis by calling
  48 wxDialog::SetLayoutAdaptationMode with one of
  49 @c wxDIALOG_ADAPTATION_MODE_DEFAULT (use the global setting),
  50 @c wxDIALOG_ADAPTATION_MODE_ENABLED or @c wxDIALOG_ADAPTATION_MODE_DISABLED.
  51
  52 The last two modes override the global adaptation setting. With adaptation
  53 enabled, if the display size is too small for the dialog, wxWidgets (or rather
  54 the standard adapter class wxStandardDialogLayoutAdapter) will make part of the
  55 dialog scrolling, leaving standard buttons in a non-scrolling part at the
  56 bottom of the dialog. This is done as follows, in
  57 wxDialogLayoutAdapter::DoLayoutAdaptation called from within wxDialog::Show or
  58 wxDialog::ShowModal:
  59
  60 @li If wxDialog::GetContentWindow returns a window derived from wxBookCtrlBase,
  61     the pages are made scrollable and no other adaptation is done.
  62 @li wxWidgets looks for a wxStdDialogButtonSizer and uses it for the
  63     non-scrolling part.
  64 @li If that search failed, wxWidgets looks for a horizontal wxBoxSizer with one
  65     or more standard buttons, with identifiers such as @c wxID_OK and
  66     @c wxID_CANCEL.
  67 @li If that search failed too, wxWidgets finds 'loose' standard buttons (in any
  68     kind of sizer) and adds them to a wxStdDialogButtonSizer. If no standard
  69     buttons were found, the whole dialog content will scroll.
  70 @li All the children apart from standard buttons are reparented onto a new
  71     ::wxScrolledWindow object, using the old top-level sizer for the scrolled
  72     window and creating a new top-level sizer to lay out the scrolled window
  73     and standard button sizer.
  74
  75
  76 @subsection overview_dialog_autoscrolling_custom Customising Scrolling Adaptation
  77
  78 In addition to switching adaptation on and off globally and per dialog, you can
  79 choose how aggressively wxWidgets will search for standard buttons by setting
  80 wxDialog::SetLayoutAdaptationLevel. By default, all the steps described above
  81 will be performed but by setting the level to 1, for example, you can choose to
  82 only look for wxStdDialogButtonSizer.
  83
  84 You can use wxDialog::AddMainButtonId to add identifiers for buttons that
  85 should also be treated as standard buttons for the non-scrolling area.
  86
  87 You can derive your own class from wxDialogLayoutAdapter or
  88 wxStandardDialogLayoutAdapter and call wxDialog::SetLayoutAdapter, deleting the
  89 old object that this function returns. Override the functions
  90 CanDoLayoutAdaptation and DoLayoutAdaptation to test for adaptation
  91 applicability and perform the adaptation.
  92
  93 You can also override wxDialog::CanDoLayoutAdaptation and
  94 wxDialog::DoLayoutAdaptation in a class derived from wxDialog.
  95
  96
  97 @subsection overview_dialog_autoscrolling_fail Where Scrolling Adaptation May Fail
  98
  99 Because adaptation rearranges your sizer and window hierarchy, it is not
 100 fool-proof, and may fail in the following situations:
 101
 102 @li The dialog doesn't use sizers.
 103 @li The dialog implementation makes assumptions about the window hierarchy,
 104     for example getting the parent of a control and casting to the dialog class.
 105 @li The dialog does custom painting and/or event handling not handled by the scrolled window.
 106     If this problem can be solved globally, you can derive a new adapter class from
 107     wxStandardDialogLayoutAdapter and override its CreateScrolledWindow function to return
 108     an instance of your own class.
 109 @li The dialog has unusual layout, for example a vertical sizer containing a mixture of
 110     standard buttons and other controls.
 111 @li The dialog makes assumptions about the sizer hierarchy, for example to show or hide
 112     children of the top-level sizer. However, the original sizer hierarchy will still hold
 113     until Show or ShowModal is called.
 114
 115 You can help make sure that your dialogs will continue to function after
 116 adaptation by:
 117
 118 @li avoiding the above situations and assumptions;
 119 @li using wxStdDialogButtonSizer;
 120 @li only making assumptions about hierarchy immediately after the dialog is created;
 121 @li using an intermediate sizer under the main sizer, a @false top-level sizer that
 122     can be relied on to exist for the purposes of manipulating child sizers and windows;
 123 @li overriding wxDialog::GetContentWindow to return a book control if your dialog implements
 124     pages: wxWidgets will then only make the pages scrollable.
 125
 126
 127 @subsection overview_dialog_propertysheet wxPropertySheetDialog and wxWizard
 128
 129 Adaptation for wxPropertySheetDialog is always done by simply making the pages
 130 scrollable, since wxDialog::GetContentWindow returns the dialog's book control
 131 and this is handled by the standard layout adapter.
 132
 133 wxWizard uses its own CanDoLayoutAdaptation and DoLayoutAdaptation functions
 134 rather than the global adapter: again, only the wizard pages are made
 135 scrollable.
 136
 137 */