qbutton.3qt

Qt/Embedded是一个多平台的C++图形用户界面应用程序框架

.TH QButton 3qt "10 November 2000" "Trolltech AS" \" -*- nroff -*-
.\" Copyright 1992-2000 Trolltech AS.  All rights reserved.  See the
.\" license file included in the distribution for a complete license
.\" statement.
.\"
.ad l
.nh
.SH NAME
QButton \- The abstract base class of button widgets, providing functionality common to buttons
.SH SYNOPSIS
.br
.PP
\fC#include <qbutton.h>\fR
.PP
Inherits QWidget.
.PP
Inherited by QCheckBox, QPushButton, QRadioButton and QToolButton.
.PP
.SS "Public Members"
.in +1c
.ti -1c
.BI "\fBQButton\fR ( QWidget * " "parent" "=0, const char * " "name" "=0, WFlags " "f" "=0 ) "
.br
.ti -1c
.BI "\fB~QButton\fR () "
.br
.ti -1c
.BI "QString \fBtext\fR () const"
.br
.ti -1c
.BI "virtual void \fBsetText\fR ( const QString & ) "
.br
.ti -1c
.BI "const QPixmap* \fBpixmap\fR () const"
.br
.ti -1c
.BI "virtual void \fBsetPixmap\fR ( const QPixmap & ) "
.br
.ti -1c
.BI "int \fBaccel\fR () const"
.br
.ti -1c
.BI "virtual void \fBsetAccel\fR ( int ) "
.br
.ti -1c
.BI "bool \fBisToggleButton\fR () const"
.br
.ti -1c
.BI "enum \fBToggleType\fR { SingleShot, Toggle, Tristate }"
.br
.ti -1c
.BI "ToggleType \fBtoggleType\fR () const"
.br
.ti -1c
.BI "virtual void \fBsetDown\fR ( bool ) "
.br
.ti -1c
.BI "bool \fBisDown\fR () const"
.br
.ti -1c
.BI "bool \fBisOn\fR () const"
.br
.ti -1c
.BI "enum \fBToggleState\fR { Off, NoChange, On }"
.br
.ti -1c
.BI "ToggleState \fBstate\fR () const"
.br
.ti -1c
.BI "bool autoResize () const \fI(obsolete)\fR"
.br
.ti -1c
.BI "virtual void setAutoResize ( bool ) \fI(obsolete)\fR"
.br
.ti -1c
.BI "bool \fBautoRepeat\fR () const"
.br
.ti -1c
.BI "virtual void \fBsetAutoRepeat\fR ( bool ) "
.br
.ti -1c
.BI "bool \fBisExclusiveToggle\fR () const"
.br
.ti -1c
.BI "QButtonGroup* \fBgroup\fR () const"
.br
.in -1c
.SS "Public Slots"
.in +1c
.ti -1c
.BI "void \fBanimateClick\fR () "
.br
.ti -1c
.BI "void \fBtoggle\fR () "
.br
.in -1c
.SS "Signals"
.in +1c
.ti -1c
.BI "void \fBpressed\fR () "
.br
.ti -1c
.BI "void \fBreleased\fR () "
.br
.ti -1c
.BI "void \fBclicked\fR () "
.br
.ti -1c
.BI "void \fBtoggled\fR ( bool ) "
.br
.ti -1c
.BI "void \fBstateChanged\fR ( int ) "
.br
.in -1c
.SS "Protected Members"
.in +1c
.ti -1c
.BI "void \fBsetToggleButton\fR ( bool ) "
.br
.ti -1c
.BI "virtual void \fBsetToggleType\fR ( ToggleType ) "
.br
.ti -1c
.BI "void \fBsetOn\fR ( bool ) "
.br
.ti -1c
.BI "virtual void \fBsetState\fR ( ToggleState ) "
.br
.ti -1c
.BI "virtual bool \fBhitButton\fR ( const QPoint & pos ) const"
.br
.ti -1c
.BI "virtual void \fBdrawButton\fR ( QPainter * ) "
.br
.ti -1c
.BI "virtual void \fBdrawButtonLabel\fR ( QPainter * ) "
.br
.ti -1c
.BI "virtual void \fBpaintEvent\fR ( QPaintEvent * ) "
.br
.in -1c
.SS "Properties"
<table border=1 cellpadding=3 cellspacing=0> <tr><th>Type<th>Name<th>READ<th>WRITE<th>Options <tr><td>QString<td>text<td>text<td>setText<td>&nbsp; <tr><td>QPixmap<td>pixmap<td>pixmap<td>setPixmap<td>&nbsp; <tr><td>int<td>accel<td>accel<td>setAccel<td>&nbsp; <tr><td>bool<td>toggleButton<td>isToggleButton<td>&nbsp;<td>&nbsp; <tr><td>ToggleType<td>toggleType<td>toggleType<td>&nbsp;<td>&nbsp; <tr><td>bool<td>down<td>isDown<td>setDown<td> DESIGNABLE false <tr><td>bool<td>on<td>isOn<td>&nbsp;<td>&nbsp; <tr><td>ToggleState<td>toggleState<td>state<td>&nbsp;<td>&nbsp; <tr><td>bool<td>autoResize<td>autoResize<td>setAutoResize<td>&nbsp; <tr><td>bool<td>autoRepeat<td>autoRepeat<td>setAutoRepeat<td>&nbsp; <tr><td>bool<td>exclusiveToggle<td>isExclusiveToggle<td>&nbsp;<td>&nbsp; </table>
.SH DESCRIPTION
The QButton class is the abstract base class of button widgets, providing functionality common to buttons.
.PP
The QButton class implements an abstract button, and lets subclasses specify how to reply to user actions and how to draw the button.
.PP
QButton provides both push and toggle buttons. The QRadioButton and QCheckBox classes provide only toggle buttons, QPushButton and QToolButton provide both toggle and push buttons.
.PP
Any button can have either a text or pixmap label. setText() sets the button to be a text button and setPixmap() sets it to be a pixmap button. The text/pixmap is manipulated as necessary to create "disabled" appearance when the button is disabled.
.PP
QButton provides most of the states used for buttons:
.TP
isDown() determines whether the button is \fIpressed\fR down.
.TP
isOn() determines whether the button is \fIon.\fR Only toggle buttons can be switched on and off (see below).
.TP
isEnabled() determines whether the button can be pressed by the user.
.TP
setAutoRepeat() determines whether the button will auto-repeat if the user holds it down.
.TP
setToggleButton() determines whether the button is a toggle button or not.
.PP
The difference between isDown() and isOn() is as follows: When the user clicks a toggle button to toggle it on, the button is first \fIpressed,\fR then released into \fIon\fR state. When the user clicks it again (to toggle it off) the button moves first to the \fIpressed\fR state, then to the \fIoff\fR state (isOn() and isDown() are both FALSE).
.PP
Default buttons (as used in many dialogs) are provided by QPushButton::setDefault() and QPushButton::setAutoDefault().
.PP
QButton provides four signals:
.TP
pressed() is emitted when the left mouse button is pressed while the mouse cursor is inside the button.
.TP
released() is emitted when the left mouse button is released.
.TP
clicked() is emitted when the button is first pressed then released, or when the accelerator key is typed, or when animateClick() is called.
.TP
toggled(bool) is emitted when the state of a toggle button changes.
.TP
stateChanged(int) is emitted when the state of a tristate toggle button changes.
.PP
If the button is a text button with "&" in its text, QButton creates an automatic accelerator key. This code creates a push button labelled "Rock & Roll" (where the c is underscored). The button gets an automatic accelerator key, Alt-C:
.PP
.nf
.br
    QPushButton *p = new QPushButton( "Ro&ck && Roll", this );
.fi
.PP
In this example, when the user presses Alt-C the button will call animateClick().
.PP
You can also set a custom accelerator using the setAccel() function. This is useful mostly for pixmap buttons since they have no automatic accelerator.
.PP
.nf
.br
    QPushButton *p;
.br
    p->setPixmap( QPixmap("print.png") );
.br
    p->setAccel( ALT+Key_F7 );
.fi
.PP
All of the buttons provided by Qt (QPushButton, QToolButton, QCheckBox and QRadioButton) can display both text and pixmaps.
.PP
To subclass QButton, you have to reimplement at least drawButton() (to draw the button's outskirts) and drawButtonLabel() (to draw its text or pixmap). It is generally advisable to reimplement sizeHint() as well, and sometimes hitButton() (to determine whether a button press is within the button).
.PP
To reduce flickering the QButton::paintEvent() sets up a pixmap that the drawButton() function draws in. You should not reimplement paintEvent() for a subclass of QButton unless you want to take over all drawing.
.PP
See also QButtonGroup.
.PP
Examples:
.(l
scrollview/scrollview.cpp
.)l
.SS "Member Type Documentation"
.SH "QButton::ToggleState"
This enum defines the state of a toggle button at any moment. The possible values are: 
.TP
\fCOff\fR - the button is in the "off" state
.TP
\fCNoChange\fR - the button is in the default/unchanged state
.TP
\fCOn\fR - the button is in the "on" state
.IP
.SH "QButton::ToggleType"
This enum type defines what a button can do in response to a mouse/keyboard press: 
.TP
\fCSingleShot\fR - pressing the button causes an action, then the button returns to the unpressed state.
.TP
\fCToggle\fR - pressing the button toggles it between an \fCOn\fR and and \fCOff\fR state.
.TP
\fCTristate\fR - pressing the button cycles between the three states \fCOn, Off\fR and \fCNoChange\fR
.IP
.SH MEMBER FUNCTION DOCUMENTATION
.SH "QButton::QButton ( QWidget * parent=0, const char * name=0, WFlags f=0 )"
Constructs a standard button with a parent widget and a name.
.PP
If \fIparent\fR is a QButtonGroup, this constructor calls QButtonGroup::insert().
.SH "QButton::~QButton ()"
Destructs the button, deleting all its child widgets.
.SH "int QButton::accel () const"
Returns the accelerator key currently set for the button, or 0 if no accelerator key has been set.
.PP
See also setAccel().
.SH "void QButton::animateClick () \fC[slot]\fR"
Performs an animated click: The button is pressed and a short while later released.