| 1 | \section{\class{wxUpdateUIEvent}}\label{wxupdateuievent} |
| 2 | |
| 3 | This class is used for pseudo-events which are called by wxWidgets |
| 4 | to give an application the chance to update various user interface elements. |
| 5 | |
| 6 | \wxheading{Derived from} |
| 7 | |
| 8 | \helpref{wxCommandEvent}{wxcommandevent}\\ |
| 9 | \helpref{wxEvent}{wxevent}\\ |
| 10 | \helpref{wxObject}{wxobject} |
| 11 | |
| 12 | \wxheading{Include files} |
| 13 | |
| 14 | <wx/event.h> |
| 15 | |
| 16 | \wxheading{Library} |
| 17 | |
| 18 | \helpref{wxCore}{librarieslist} |
| 19 | |
| 20 | \wxheading{Event table macros} |
| 21 | |
| 22 | To process an update event, use these event handler macros to direct input to member |
| 23 | functions that take a wxUpdateUIEvent argument. |
| 24 | |
| 25 | \twocolwidtha{7cm} |
| 26 | \begin{twocollist}\itemsep=0pt |
| 27 | \twocolitem{{\bf EVT\_UPDATE\_UI(id, func)}}{Process a wxEVT\_UPDATE\_UI event for the command with the given id.} |
| 28 | \twocolitem{{\bf EVT\_UPDATE\_UI\_RANGE(id1, id2, func)}}{Process a wxEVT\_UPDATE\_UI event for any command with id included in the given range.} |
| 29 | \end{twocollist} |
| 30 | |
| 31 | \wxheading{Remarks} |
| 32 | |
| 33 | Without update UI events, an application has to work hard to check/uncheck, enable/disable, |
| 34 | show/hide, and set the text for elements such as menu items and toolbar buttons. |
| 35 | The code for doing this has to be mixed up with the code that is invoked when |
| 36 | an action is invoked for a menu item or button. |
| 37 | |
| 38 | With update UI events, you define an event handler to look at the state of |
| 39 | the application and change UI elements accordingly. wxWidgets will call your |
| 40 | member functions in idle time, so you don't have to worry where to call this code. |
| 41 | In addition to being a clearer and more declarative method, it also means you |
| 42 | don't have to worry whether you're updating a toolbar or menubar identifier. |
| 43 | The same handler can update a menu item and toolbar button, if the identifier is the same. |
| 44 | |
| 45 | Instead of directly manipulating the menu or button, you call functions in the event |
| 46 | object, such as \helpref{wxUpdateUIEvent::Check}{wxupdateuieventcheck}. wxWidgets |
| 47 | will determine whether such a call has been made, and which UI element to update. |
| 48 | |
| 49 | These events will work for popup menus as well as menubars. Just before a menu is popped |
| 50 | up, \helpref{wxMenu::UpdateUI}{wxmenuupdateui} is called to process any UI events for |
| 51 | the window that owns the menu. |
| 52 | |
| 53 | If you find that the overhead of UI update processing is affecting |
| 54 | your application, you can do one or both of the following: |
| 55 | |
| 56 | \begin{enumerate} |
| 57 | \item Call \helpref{wxUpdateUIEvent::SetMode}{wxupdateuieventsetmode} with |
| 58 | a value of wxUPDATE\_UI\_PROCESS\_SPECIFIED, and set the extra style |
| 59 | wxWS\_EX\_PROCESS\_UI\_UPDATES for every window that should receive update events. |
| 60 | No other windows will receive update events. |
| 61 | \item Call \helpref{wxUpdateUIEvent::SetUpdateInterval}{wxupdateuieventsetupdateinterval} with |
| 62 | a millisecond value to set the delay between updates. You may need |
| 63 | to call \helpref{wxWindow::UpdateWindowUI}{wxwindowupdatewindowui} at critical |
| 64 | points, for example when a dialog is about to be shown, in case the user |
| 65 | sees a slight delay before windows are updated. |
| 66 | \end{enumerate} |
| 67 | |
| 68 | Note that although events are sent in idle time, defining a wxIdleEvent |
| 69 | handler for a window does not affect this because the events are sent from \helpref{wxWindow::OnInternalIdle}{wxwindowoninternalidle} |
| 70 | which is {\bf always} called in idle time. |
| 71 | |
| 72 | wxWidgets tries to optimize update events on some platforms. On Windows |
| 73 | and GTK+, events for menubar items are only sent when the menu is about |
| 74 | to be shown, and not in idle time. |
| 75 | |
| 76 | \wxheading{See also} |
| 77 | |
| 78 | \helpref{Event handling overview}{eventhandlingoverview} |
| 79 | |
| 80 | \latexignore{\rtfignore{\wxheading{Members}}} |
| 81 | |
| 82 | \membersection{wxUpdateUIEvent::wxUpdateUIEvent}\label{wxupdateuieventctor} |
| 83 | |
| 84 | \func{}{wxUpdateUIEvent}{\param{wxWindowID }{commandId = 0}} |
| 85 | |
| 86 | Constructor. |
| 87 | |
| 88 | \membersection{wxUpdateUIEvent::CanUpdate}\label{wxupdateuieventcanupdate} |
| 89 | |
| 90 | \func{static bool}{CanUpdate}{\param{wxWindow*}{ window}} |
| 91 | |
| 92 | Returns {\tt true} if it is appropriate to update (send UI update events to) |
| 93 | this window. |
| 94 | |
| 95 | This function looks at the mode used (see \helpref{wxUpdateUIEvent::SetMode}{wxupdateuieventsetmode}), |
| 96 | the wxWS\_EX\_PROCESS\_UI\_UPDATES flag in {\it window}, |
| 97 | the time update events were last sent in idle time, and |
| 98 | the update interval, to determine whether events should be sent to |
| 99 | this window now. By default this will always return {\tt true} because |
| 100 | the update mode is initially wxUPDATE\_UI\_PROCESS\_ALL and |
| 101 | the interval is set to 0; so update events will be sent as |
| 102 | often as possible. You can reduce the frequency that events |
| 103 | are sent by changing the mode and/or setting an update interval. |
| 104 | |
| 105 | \wxheading{See also} |
| 106 | |
| 107 | \helpref{wxUpdateUIEvent::ResetUpdateTime}{wxupdateuieventresetupdatetime}, |
| 108 | \helpref{wxUpdateUIEvent::SetUpdateInterval}{wxupdateuieventsetupdateinterval}, |
| 109 | \helpref{wxUpdateUIEvent::SetMode}{wxupdateuieventsetmode} |
| 110 | |
| 111 | \membersection{wxUpdateUIEvent::Check}\label{wxupdateuieventcheck} |
| 112 | |
| 113 | \func{void}{Check}{\param{bool}{ check}} |
| 114 | |
| 115 | Check or uncheck the UI element. |
| 116 | |
| 117 | \membersection{wxUpdateUIEvent::Enable}\label{wxupdateuieventenable} |
| 118 | |
| 119 | \func{void}{Enable}{\param{bool}{ enable}} |
| 120 | |
| 121 | Enable or disable the UI element. |
| 122 | |
| 123 | \membersection{wxUpdateUIEvent::Show}\label{wxupdateuieventshow} |
| 124 | |
| 125 | \func{void}{Show}{\param{bool}{ show}} |
| 126 | |
| 127 | Show or hide the UI element. |
| 128 | |
| 129 | \membersection{wxUpdateUIEvent::GetChecked}\label{wxupdateuieventgetchecked} |
| 130 | |
| 131 | \constfunc{bool}{GetChecked}{\void} |
| 132 | |
| 133 | Returns true if the UI element should be checked. |
| 134 | |
| 135 | \membersection{wxUpdateUIEvent::GetEnabled}\label{wxupdateuieventgetenabled} |
| 136 | |
| 137 | \constfunc{bool}{GetEnabled}{\void} |
| 138 | |
| 139 | Returns true if the UI element should be enabled. |
| 140 | |
| 141 | \membersection{wxUpdateUIEvent::GetShown}\label{wxupdateuieventgetshown} |
| 142 | |
| 143 | \constfunc{bool}{GetShown}{\void} |
| 144 | |
| 145 | Returns true if the UI element should be shown. |
| 146 | |
| 147 | \membersection{wxUpdateUIEvent::GetSetChecked}\label{wxupdateuieventgetsetchecked} |
| 148 | |
| 149 | \constfunc{bool}{GetSetChecked}{\void} |
| 150 | |
| 151 | Returns true if the application has called \helpref{wxUpdateUIEvent::Check}{wxupdateuieventcheck}. For wxWidgets internal use only. |
| 152 | |
| 153 | \membersection{wxUpdateUIEvent::GetSetEnabled}\label{wxupdateuieventgetsetenabled} |
| 154 | |
| 155 | \constfunc{bool}{GetSetEnabled}{\void} |
| 156 | |
| 157 | Returns true if the application has called \helpref{wxUpdateUIEvent::Enable}{wxupdateuieventenable}. For wxWidgets internal use only. |
| 158 | |
| 159 | \membersection{wxUpdateUIEvent::GetSetShown}\label{wxupdateuieventgetsetshown} |
| 160 | |
| 161 | \constfunc{bool}{GetSetShown}{\void} |
| 162 | |
| 163 | Returns true if the application has called \helpref{wxUpdateUIEvent::Show}{wxupdateuieventshow}. For wxWidgets internal use only. |
| 164 | |
| 165 | \membersection{wxUpdateUIEvent::GetSetText}\label{wxupdateuieventgetsettext} |
| 166 | |
| 167 | \constfunc{bool}{GetSetText}{\void} |
| 168 | |
| 169 | Returns true if the application has called \helpref{wxUpdateUIEvent::SetText}{wxupdateuieventsettext}. For wxWidgets internal use only. |
| 170 | |
| 171 | \membersection{wxUpdateUIEvent::GetText}\label{wxupdateuieventgettext} |
| 172 | |
| 173 | \constfunc{wxString}{GetText}{\void} |
| 174 | |
| 175 | Returns the text that should be set for the UI element. |
| 176 | |
| 177 | \membersection{wxUpdateUIEvent::GetMode}\label{wxupdateuieventgetmode} |
| 178 | |
| 179 | \func{static wxUpdateUIMode}{GetMode}{\void} |
| 180 | |
| 181 | Static function returning a value specifying how wxWidgets |
| 182 | will send update events: to all windows, or only to those which specify that they |
| 183 | will process the events. |
| 184 | |
| 185 | See \helpref{wxUpdateUIEvent::SetMode}{wxupdateuieventsetmode}. |
| 186 | |
| 187 | \membersection{wxUpdateUIEvent::GetUpdateInterval}\label{wxupdateuieventgetupdateinterval} |
| 188 | |
| 189 | \func{static long}{GetUpdateInterval}{\void} |
| 190 | |
| 191 | Returns the current interval between updates in milliseconds. |
| 192 | -1 disables updates, 0 updates as frequently as possible. |
| 193 | |
| 194 | See \helpref{wxUpdateUIEvent::SetUpdateInterval}{wxupdateuieventsetupdateinterval}. |
| 195 | |
| 196 | \membersection{wxUpdateUIEvent::ResetUpdateTime}\label{wxupdateuieventresetupdatetime} |
| 197 | |
| 198 | \func{static void}{ResetUpdateTime}{\void} |
| 199 | |
| 200 | Used internally to reset the last-updated time to the |
| 201 | current time. It is assumed that update events are |
| 202 | normally sent in idle time, so this is called at the end of |
| 203 | idle processing. |
| 204 | |
| 205 | \wxheading{See also} |
| 206 | |
| 207 | \helpref{wxUpdateUIEvent::CanUpdate}{wxupdateuieventcanupdate}, |
| 208 | \helpref{wxUpdateUIEvent::SetUpdateInterval}{wxupdateuieventsetupdateinterval}, |
| 209 | \helpref{wxUpdateUIEvent::SetMode}{wxupdateuieventsetmode} |
| 210 | |
| 211 | \membersection{wxUpdateUIEvent::SetMode}\label{wxupdateuieventsetmode} |
| 212 | |
| 213 | \func{static void}{SetMode}{\param{wxUpdateUIMode }{mode}} |
| 214 | |
| 215 | Specify how wxWidgets will send update events: to |
| 216 | all windows, or only to those which specify that they |
| 217 | will process the events. |
| 218 | |
| 219 | {\it mode} may be one of the following values. |
| 220 | The default is wxUPDATE\_UI\_PROCESS\_ALL. |
| 221 | |
| 222 | \begin{verbatim} |
| 223 | enum wxUpdateUIMode |
| 224 | { |
| 225 | // Send UI update events to all windows |
| 226 | wxUPDATE_UI_PROCESS_ALL, |
| 227 | |
| 228 | // Send UI update events to windows that have |
| 229 | // the wxWS_EX_PROCESS_UI_UPDATES flag specified |
| 230 | wxUPDATE_UI_PROCESS_SPECIFIED |
| 231 | }; |
| 232 | \end{verbatim} |
| 233 | |
| 234 | \membersection{wxUpdateUIEvent::SetText}\label{wxupdateuieventsettext} |
| 235 | |
| 236 | \func{void}{SetText}{\param{const wxString\&}{ text}} |
| 237 | |
| 238 | Sets the text for this UI element. |
| 239 | |
| 240 | \membersection{wxUpdateUIEvent::SetUpdateInterval}\label{wxupdateuieventsetupdateinterval} |
| 241 | |
| 242 | \func{static void}{SetUpdateInterval}{\param{long }{updateInterval}} |
| 243 | |
| 244 | Sets the interval between updates in milliseconds. |
| 245 | Set to -1 to disable updates, or to 0 to update as frequently as possible. |
| 246 | The default is 0. |
| 247 | |
| 248 | Use this to reduce the overhead of UI update events if your application |
| 249 | has a lot of windows. If you set the value to -1 or greater than 0, |
| 250 | you may also need to call \helpref{wxWindow::UpdateWindowUI}{wxwindowupdatewindowui} |
| 251 | at appropriate points in your application, such as when a dialog |
| 252 | is about to be shown. |
| 253 | |