This section discusses how selecting a button changes its state and how the application should respond. The two tabbing methods are part of the predefined keyboard interface provided by the system. For a complete description of this interface, see Dialog Boxes. The focus state applies to a check box, radio button, push button, or owner-drawn button.
A button receives the keyboard focus when the user selects it and loses the focus when the user selects another control. Only one control can have the keyboard focus at a time. When a button has the keyboard focus, the system typically highlights the text, icon, or bitmap of a button by surrounding it with a dotted line.
In addition, a push button has a heavy dark border when it has the focus. The system automatically changes the highlight for an automatic button, but the application must change the highlight for a non-automatic button by sending messages.
The push state applies to a push button, check box, radio button, or three-state check box, but does not apply to other buttons. The push state of a button can be either pushed or not pushed. When it is not pushed, it is drawn as a raised button.
When a check box, radio button, or three-state check box is clicked, the background of the button is grayed. When it is not pushed, the background of the button is not grayed. The check state applies to a check box, radio button, or three-state check box, but does not apply to other buttons. The state can be checked, cleared, or for three-state check boxes indeterminate.
A check box is checked when it contains a check mark, and is cleared when it does not. A radio button is checked when it contains a black dot; it is cleared when it does not. A three-state check box is checked when it contains a check mark, is cleared when it does not, and is indeterminate when it contains a grayed box. The system automatically changes the check state of an automatic button, but the application must change the check state of a non-automatic button.
When the user selects a button, it is generally necessary to change one or more of the button's state elements.In this part of the PyQt4 programming tutorial, we will explore events and signals occurring in applications. All GUI applications are event-driven. Events are generated mainly by the user of an application. But they can be generated by other means as well: e. The main loop fetches events and sends them to the objects.
The event source is the object whose state changes. It generates events. The event object event encapsulates the state changes in the event source. The event target is the object that wants to be notified.
Event source object delegates the task of handling an event to the event target. PyQt4 has a unique signal and slot mechanism to deal with events. Signals and slots are used for communication between objects. A signal is emitted when a particular event occurs. A slot can be any Python callable. A slot is called when a signal connected to it is emitted. In our example, we display a QtGui. We change the lcd number by dragging the slider knob. Here we connect a valueChanged signal of the slider to the display slot of the lcd number.
The sender is an object that sends a signal. The receiver is the object that receives the signal. The slot is the method that reacts to the signal.
Sometimes it is convenient to know which widget is the sender of a signal. For this, PyQt4 has the sender method.The QRadiobutton widget has also the text label together with the round radio button. The below code asks which city you live in and creates two radio buttons for the user to choose. It displays the in the label text after the user selects one of the radio buttons. We create two radio buttons rbtn1 and rbtn2. The string in the parenthesis is the text label shown next to the round radio button.
The button emits the toggled signal every time the button is selected or deselected. The onClicked function is connected to the toggled signal of two radio buttons. We could get the particular radio button that is selected from the group of radio buttons by checking the isChecked method. The QRadiobutton is not checked by default after it is initiated. We could change the default the state of the radio button to be Checked during initialization by using setChecked method.
For example, we add the below line to the above example codes to check the radio button New York. All the radio buttons in the same parent window are within the same group and it means that only one radio button could be selected at one time even the toggled signals are connected to different functions.
QButtonGroup from QtWidgets groups the selected buttons together and we could create multiple QButtonGroup instances to isolate radio buttons from different groups so that more buttons could be checked in the same parent widget.
The following shows the example to ask the user to select both city and state from two groups of radio buttons. QRadiobutton Basic Example. PyQt5 Tutorial - MenuBar.The QAbstractButton class is the abstract base class of button widgets, providing functionality common to buttons. More …. This class implements an abstract button. Subclasses of this class handle user actions, and specify how the button is drawn. QAbstractButton provides support for both push buttons and checkable toggle buttons.
Push buttons are implemented in the QPushButton and QToolButton classes; these also provide toggle behavior if required. Any button can display a label containing text and an icon. For example:. See the QShortcut documentation for details.
You can also set a custom shortcut key using the setShortcut function. A button can be made the default button in a dialog by means of setDefault and setAutoDefault. QAbstractButton provides most of the states used for buttons:. Only checkable buttons can be checked and unchecked see below. As opposed to other widgets, buttons derived from QAbstractButton accept mouse and context menu events when disabled.
The difference between isDown and isChecked is as follows. When the user clicks a toggle button to check it, the button is first pressed then released into the checked state. When the user clicks it again to uncheck itthe button moves first to the pressed state, then to the unchecked state isChecked and isDown are both false. QAbstractButton provides four signals:. It is generally advisable to reimplement sizeHint as well, and sometimes hitButton to determine whether a button press is within the button.
For buttons with more than two states like tri-state buttonsyou will also have to reimplement checkStateSet and nextCheckState. Constructs an abstract button with a parent. Performs an animated click: the button is pressed immediately, and released msec milliseconds later the default is ms. This function does nothing if the button is PySide2. This virtual handler is called when setChecked is used, unless it is called from within nextCheckState.
The dark mode beta is finally here. Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. I started learning pyQt and I want a button which will be when clicked always in pressed state and when it's going to be clicked againit's going to be released. I guess it can be achieved with QtWidgets. QPushButton, but which flags to use I don't know.
I tried to read all of thembut a lot still looks so hard to grasp.PyQt5 Lesson 3 PushButton
Can anybody help newbie? Note: this flag is not available in Qt Creator and must be set programatically. Learn more. Create button which will be in pressed state when it's clicked Ask Question. Asked 2 years ago. Active 2 years ago. Viewed 83 times. Vlad Vlad 1 1 silver badge 10 10 bronze badges. Active Oldest Votes. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name.
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Checkboxes are typically used to represent features in an application that can be enabled or disabled without affecting others, but different types of behavior can be implemented. For example, a QButtonGroup can be used to group check buttons logically, allowing exclusive checkboxes.
However, QButtonGroup does not provide any visual representation. The image below further illustrates the differences between exclusive and non-exclusive checkboxes. Whenever a checkbox is checked or cleared it emits the signal stateChanged. Connect to this signal if you want to trigger an action each time the checkbox changes state. You can use isChecked to query whether or not a checkbox is checked.
In addition to the usual checked and unchecked states, QCheckBox optionally provides a third state to indicate "no change". This is useful whenever you need to give the user the option of neither checking nor unchecking a checkbox. If you need this third state, enable it with setTristateand use checkState to query the current toggle state. Just like QPushButtona checkbox displays text, and optionally a small icon. The icon is set with setIcon. The text can be set in the constructor or with setText.
A shortcut key can be specified by preceding the preferred character with an ampersand. For example:. Important inherited functions: textsetTexttextpixmapsetPixmapaccelsetAccelisToggleButtonsetDownisDownisOncheckStateautoRepeatisExclusiveTogglegroupsetAutoRepeattogglepressedreleasedclickedtoggledcheckStateand stateChanged. Returns the check box's check state. If you do not need tristate support, you can also use QAbstractButton. See also setCheckState and Qt. Reimplemented from QAbstractButton.
Initializes option with the values from this QCheckBox. This method is useful for subclasses that require a QStyleOptionButtonbut do not want to fill in all the information themselves.
Sets the check box's check state to state. See also checkState and Qt. This signal is emitted whenever the check box's state changes, i. A checkbox shown in the Macintosh widget style. A checkbox shown in the Windows XP widget style. A checkbox shown in the Plastique widget style. Method Documentation QCheckBox. Constructs a checkbox with the given parentbut with no text. Constructs a checkbox with the given parent and text. CheckState QCheckBox. See also QStyleOption.
This function was introduced in Qt 4.The QPushButton widget provides a command button.
PyQt - QCheckBox Widget
More …. Inherited by: QCommandLinkButton. The push button, or command button, is perhaps the most commonly used widget in any graphical user interface.
Push click a button to command the computer to perform some action, or to answer a question. A command button is rectangular and typically displays a text label describing its action. A shortcut key can be specified by preceding the preferred character with an ampersand in the text.
For example:. Push buttons display a textual label, and optionally a small icon. These can be set using the constructors and changed later using setText and setIcon.
A push button emits the signal clicked when it is activated by the mouse, the Spacebar or by a keyboard shortcut. Push buttons also provide less commonly used signals, for example pressed and released. Command buttons in dialogs are by default auto-default buttons, i. A default button is a push button that is activated when the user presses the Enter or Return key in a dialog. You can change this with setAutoDefault. Note that auto-default buttons reserve a little extra space which is necessary to draw a default-button indicator.
If you do not want this space around your buttons, call setAutoDefault false. Being so central, the button widget has grown to accommodate a great many variations in the past decade.
The Microsoft style guide now shows about ten different states of Windows push buttons and the text implies that there are dozens more when all the combinations of features are taken into consideration. Default or normal. As a general rule, use a push button when the application or dialog window performs an action when the user clicks on it such as Apply, Cancel, Close and Help and when the widget is supposed to have a wide, rectangular shape with a text label.
Small, typically square buttons that change the state of the window rather than performing an action such as the buttons in the top-right corner of the QFileDialog are not command buttons, but tool buttons.
Qt provides a special class QToolButton for these buttons. If you need toggle behavior see setCheckable or a button that auto-repeats the activation signal when being pushed down like the arrows in a scroll bar see setAutoRepeata command button is probably not what you want.