xref: /haiku/docs/user/interface/Control.dox (revision 04a0e9c7b68cbe3a43d38e2bca8e860fd80936fb)
1/*
2 * Copyright 2011-2013 Haiku Inc. All rights reserved.
3 * Distributed under the terms of the MIT License.
4 *
5 * Authors:
6 *		John Scipione, jscipione@gmail.com
7 *
8 * Corresponds to:
9 *		headers/os/interface/Control.h	 rev 42794
10 *		src/kits/interface/Control.cpp	 rev 42794
11 */
12
13
14/*!
15	\file Control.h
16	\ingroup interface
17	\ingroup libbe
18	\brief BControl class definition and support enums.
19*/
20
21
22/*!
23	\var B_CONTROL_ON
24
25	Control on. Value equal to 1.
26*/
27
28
29/*!
30	\var B_CONTROL_OFF
31
32	Control off. Value equal to 0.
33*/
34
35
36/*!
37	\class BControl
38	\ingroup interface
39	\ingroup libbe
40	\brief BControl is the base class for user-event handling objects.
41
42	Simple controls such as BCheckBox and BButton deviate only a bit from
43	BControl, whereas more complicated controls such as BColorControl and
44	BSlider re-implement much more functionality. Whether you are building
45	a simple control or something more complicated you should inherit from
46	BControl as it provides a common set of methods for intercepting
47	received messages from mouse and keyboard events.
48
49	Controls have state which they keep in their value. The value of a
50	control, stored as an int32, is read and set by the virtual Value() and
51	SetValue() methods. BControl defines \c B_CONTROL_ON and \c B_CONTROL_OFF
52	values that you can use as a convenience if your control has a simple
53	on/off state. If your BControl derived class stores a larger set of
54	states then you should define your own integer values instead.
55*/
56
57
58/*!
59	\fn BControl::BControl(BRect frame, const char* name, const char* label,
60		BMessage* message, uint32 resizingMode, uint32 flags)
61	\brief Construct a control in the \a frame with a \a name, \a label,
62	       model \a message, \a resizingMode, and creation \a flags.
63
64	The initial value of the control is set to 0 (\c B_CONTROL_OFF).
65	The \a label and the \a message parameters can be set to \c NULL.
66
67	\param frame The \a frame to draw the control in.
68	\param name The \a name of the control.
69	\param label The \a label displayed along with the control.
70	\param message The \a message to send when the control is activated.
71	\param resizingMode Defines the behavior of the control as the parent
72	       view resizes, see BView for more details.
73	\param flags Behavior \a flags for the control, see BView for details.
74*/
75
76
77/*!
78	\fn BControl::BControl(const char* name, const char* label,
79		BMessage* message, uint32 flags)
80	\brief Construct a control with a \a name, \a label, model \a message,
81	       and creation \a flags suitable for use with the Layout API.
82
83	The initial value of the control is set to 0 (\c B_CONTROL_OFF).
84	The \a label and the \a message parameters can be set to \c NULL.
85
86	\note This method was not available in BeOS R5.
87
88	\param name The \a name of the control.
89	\param label The \a label displayed along with the control.
90	\param message The \a message to send when the control is activated.
91	\param flags Behavior \a flags for the control, see BView for details.
92*/
93
94
95/*!
96	\fn BControl::~BControl()
97	\brief Frees all memory used by the BControl object including the memory
98	       used by the model message.
99*/
100
101
102/*!
103	\fn BControl::BControl(BMessage* archive)
104	\brief Creates a new BControl object from an \a archive message.
105
106	This method is usually not called directly. If you want to build a
107	control from a message you should call Instantiate() which can
108	handle errors properly.
109
110	If the \a archive deep, the BControl object will also unarchive each
111	of its child views recursively.
112
113	\param archive The \a archive message to restore from.
114*/
115
116
117/*!
118	\fn BArchivable* BControl::Instantiate(BMessage* archive)
119	\brief Creates a new object from an \a archive.
120
121	If the message is a valid object then the instance created from the
122	passed in \a archive will be returned. Otherwise this method will
123	return \c NULL.
124
125	\param archive The \a archive message.
126
127	\returns An instance of the object if \a archive is valid or \c NULL.
128
129	\sa BArchivable::Instantiate()
130*/
131
132
133/*!
134	\fn status_t BControl::Archive(BMessage* archive, bool deep) const
135	\brief Archives the control into \a archive.
136
137	\param archive The target \a archive that the data will go into.
138	\param deep Whether or not to recursively archive child views.
139
140	\retval B_OK The archive operation was successful.
141	\retval B_BAD_VALUE \c NULL \a archive message.
142	\retval B_ERROR The archive operation failed.
143
144	\sa BArchivable::Archive()
145*/
146
147
148/*!
149	\fn void BControl::WindowActivated(bool active)
150	\brief Hook method called when the attached window is activated or
151	       deactivated.
152
153	Redraws the focus ring around the menu field when the window is activated
154	or deactivated if it is the window's current focus view.
155
156	\param active \c true if the window becomes activated, \c false if the
157	       window becomes deactivated.
158
159	\sa BView::WindowActivated()
160*/
161
162
163/*!
164	\fn void BControl::AttachedToWindow()
165	\brief Hook method called when the control is attached to a window.
166
167	This method overrides BView::AttachedToWindow() setting the low color
168	and view color of the BControl so that it matches the view color of the
169	control's parent view. It also makes the attached window the default
170	target for Invoke() as long as another target has not already been set.
171
172	\sa BView::AttachedToWindow()
173	\sa Invoke()
174	\sa BInvoker::SetTarget()
175*/
176
177
178/*!
179	\fn void BControl::DetachedFromWindow()
180	\brief Hook method called when the object is detached from a
181		window.
182
183	\sa BView::DetachedFromWindow()
184*/
185
186
187/*!
188	\fn void BControl::AllAttached()
189	\brief Similar to AttachedToWindow() but this method is triggered after
190	       all child views have already been attached to a window.
191
192	\sa BView::AllAttached()
193*/
194
195
196/*!
197	\fn void BControl::AllDetached()
198	\brief Similar to AttachedToWindow() but this method is triggered after
199	       all child views have already been detached from a window.
200
201	\sa BView::AllDetached()
202*/
203
204
205/*!
206	\fn void BControl::MakeFocus(bool focused)
207	\brief Gives or removes focus from the control.
208
209	BControl::MakeFocus() overrides BView::MakeFocus() to call Draw() when
210	the focus changes. Derived classes generally don't have to re-implement
211	MakeFocus().
212
213	IsFocusChanging() returns \c true when Draw() is called from this method.
214
215	\param focused \a true to set focus, \a false to remove it.
216
217	\sa BView::MakeFocus()
218	\sa IsFocusChanging()
219*/
220
221
222/*!
223	\fn void BControl::KeyDown(const char *bytes, int32 numBytes)
224	\brief Hook method called when a keyboard key is pressed.
225
226	Overrides BView::KeyDown() to toggle the control value and then
227	calls Invoke() for \c B_SPACE or \c B_ENTER. If this is not desired
228	you should override this method in derived classes.
229
230	The KeyDown() method is only called if the BControl is the focus view
231	in the active window. If the window has a default button, \c B_ENTER
232	will be passed to that object instead of the focus view.
233
234	\param bytes The bytes of the key combination pressed.
235	\param numBytes The number of bytes in \a bytes.
236
237	\sa BView::KeyDown()
238	\sa MakeFocus()
239*/
240
241
242/*!
243	\fn void BControl::MouseDown(BPoint point)
244	\brief Hook method called when a mouse button is pressed.
245
246	\param point The point on the screen where to mouse pointer is when
247	       the mouse button is pressed.
248
249	\sa BView::MouseDown()
250*/
251
252
253/*!
254	\fn void BControl::MouseUp(BPoint point)
255	\brief Hook method called when a mouse button is released.
256
257	\param point The point on the screen where to mouse pointer is when
258	       the mouse button is released.
259
260	\sa BView::MouseUp()
261*/
262
263
264/*!
265	\fn void BControl::MouseMoved(BPoint point, uint32 transit,
266		const BMessage *message)
267	\brief Hook method called when the mouse is moved.
268
269	\sa BView::MouseMoved()
270*/
271
272
273/*!
274	\fn void BControl::SetLabel(const char *label)
275	\brief Sets the \a label of the control.
276
277	If the \a label changes the control is redrawn.
278
279	\param label The \a label to set, can be \c NULL.
280*/
281
282
283/*!
284	\fn const char* BControl::Label() const
285	\brief Gets the label of the control.
286
287	\return The control's label.
288*/
289
290
291/*!
292	\fn void BControl::SetValue(int32 value)
293	\brief Sets the value of the control.
294
295	If the \a value changes the control is redrawn.
296
297	\param value The \a value to set.
298
299	\sa SetValueNoUpdate()
300*/
301
302
303/*!
304	\fn void BControl::SetValueNoUpdate(int32 value)
305	\brief Sets the value of the control without redrawing.
306
307	\note This method was not available in BeOS R5.
308
309	\param value The \a value to set.
310
311	\sa SetValue()
312*/
313
314
315/*!
316	\fn int32 BControl::Value() const
317	\brief Gets the value of the control.
318
319	\return The control's value.
320*/
321
322
323/*!
324	\fn void BControl::SetEnabled(bool enabled)
325	\brief Enables or disables the control.
326
327	BControl objects are enabled by default. If the control changes enabled
328	state then it is redrawn.
329
330	Disabled controls generally won't allow the user to focus on them
331	(The \c B_NAVIGABLE flag is turned off), and don't post any messages.
332
333	Disabled controls in derived classes should be drawn in subdued colors
334	to visually indicate that they are disabled and should not respond to
335	keyboard or mouse events.
336
337	\param enabled If \c true enables the control, if \c false, disables it.
338*/
339
340
341/*!
342	\fn bool BControl::IsEnabled() const
343	\brief Gets whether or not the control is currently enabled.
344
345	\return \c true if the control is enabled, \c false if it is disabled.
346*/
347
348
349/*!
350	\fn void BControl::GetPreferredSize(float *_width, float *_height)
351	\brief Fill out the preferred width and height of the control
352		into the \a _width and \a _height parameters.
353
354	Derived classes can override this method to set the preferred
355	width and height of the control.
356
357	\param _width Pointer to a \c float to hold the width of the control.
358	\param _height Pointer to a \c float to hold the height of the control.
359
360	\sa BView::GetPreferredSize()
361*/
362
363
364/*!
365	\fn void BControl::ResizeToPreferred()
366	\brief Resize the control to its preferred size.
367
368	\sa BView::ResizeToPreferred()
369*/
370
371
372/*!
373	\fn status_t BControl::Invoke(BMessage* message)
374	\brief Sends a copy of the model \a message to the designated target.
375
376	BControl::Invoke() overrides BInvoker::Invoke(). Derived classes
377	should use this method in their MouseDown() and KeyDown() methods
378	and should call IsEnabled() to check if the control is enabled
379	before calling Invoke().
380
381	The following fields added to the BMessage:
382		- "when"	\c B_INT64_TYPE	system_time()
383		- "source"	\c B_POINTER_TYPE	A pointer to the BControl object.
384
385	\param message The \a message to send.
386
387	\sa BInvoker::Invoke()
388	\sa IsEnabled()
389*/
390
391
392/*!
393	\fn BHandler* BControl::ResolveSpecifier(BMessage* message, int32 index,
394		BMessage* specifier, int32 what, const char* property)
395	\brief Determine the proper specifier for scripting messages.
396
397	\sa BHandler::ResolveSpecifier()
398*/
399
400
401/*!
402	\fn status_t BControl::GetSupportedSuites(BMessage* message)
403	\brief Report the suites of understood messages.
404
405	\sa BHandler::GetSupportedSuites();
406*/
407
408
409/*!
410	\fn status_t BControl::Perform(perform_code code, void* _data)
411	\brief Perform some action. (Internal Method)
412
413	The following perform codes are recognized:
414		- \c PERFORM_CODE_MIN_SIZE
415		- \c PERFORM_CODE_MAX_SIZE
416		- \c PERFORM_CODE_PREFERRED_SIZE
417		- \c PERFORM_CODE_LAYOUT_ALIGNMENT
418		- \c PERFORM_CODE_HAS_HEIGHT_FOR_WIDTH
419		- \c PERFORM_CODE_GET_HEIGHT_FOR_WIDTH
420		- \c PERFORM_CODE_SET_LAYOUT
421		- \c PERFORM_CODE_INVALIDATE_LAYOUT
422		- \c PERFORM_CODE_DO_LAYOUT
423
424	\param code The perform code.
425	\param _data A pointer to store some data.
426
427	\returns A status code.
428
429	\sa BHandler::Perform()
430*/
431