QProgressBar Class
The QProgressBar widget provides a horizontal or vertical progress bar. More...
| Header: | #include <QProgressBar> |
| qmake: | QT += widgets |
| Inherits: | QWidget |
Public Types
| enum | Direction { TopToBottom, BottomToTop } |
Properties
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Public Functions
| QProgressBar(QWidget *parent = nullptr) | |
| virtual | ~QProgressBar() |
| Qt::Alignment | alignment() const |
| QString | format() const |
| bool | invertedAppearance() const |
| bool | isTextVisible() const |
| int | maximum() const |
| int | minimum() const |
| Qt::Orientation | orientation() const |
| void | resetFormat() |
| void | setAlignment(Qt::Alignment alignment) |
| void | setFormat(const QString &format) |
| void | setInvertedAppearance(bool invert) |
| void | setTextDirection(QProgressBar::Direction textDirection) |
| void | setTextVisible(bool visible) |
| virtual QString | text() const |
| QProgressBar::Direction | textDirection() const |
| int | value() const |
Reimplemented Public Functions
| virtual QSize | minimumSizeHint() const override |
| virtual QSize | sizeHint() const override |
Public Slots
| void | reset() |
| void | setMaximum(int maximum) |
| void | setMinimum(int minimum) |
| void | setOrientation(Qt::Orientation) |
| void | setRange(int minimum, int maximum) |
| void | setValue(int value) |
Signals
| void | valueChanged(int value) |
Protected Functions
| void | initStyleOption(QStyleOptionProgressBar *option) const |
Reimplemented Protected Functions
| virtual bool | event(QEvent *e) override |
| virtual void | paintEvent(QPaintEvent *) override |
Detailed Description
A progress bar is used to give the user an indication of the progress of an operation and to reassure them that the application is still running.
The progress bar uses the concept of steps. You set it up by specifying the minimum and maximum possible step values, and it will display the percentage of steps that have been completed when you later give it the current step value. The percentage is calculated by dividing the progress (value() - minimum()) divided by maximum() - minimum().
You can specify the minimum and maximum number of steps with setMinimum() and setMaximum. The current number of steps is set with setValue(). The progress bar can be rewound to the beginning with reset().
If minimum and maximum both are set to 0, the bar shows a busy indicator instead of a percentage of steps. This is useful, for example, when using QNetworkAccessManager to download items when they are unable to determine the size of the item being downloaded.
See also QProgressDialog and GUI Design Handbook: Progress Indicator.
Member Type Documentation
enum QProgressBar::Direction
Specifies the reading direction of the text for vertical progress bars.
| Constant | Value | Description |
|---|---|---|
QProgressBar::TopToBottom | 0 | The text is rotated 90 degrees clockwise. |
QProgressBar::BottomToTop | 1 | The text is rotated 90 degrees counter-clockwise. |
Note that whether or not the text is drawn is dependent on the style. Currently CleanLooks and Plastique draw the text. Mac, Windows and WindowsVista style do not.
This enum was introduced or modified in Qt 4.1.
See also textDirection.
Property Documentation
alignment : Qt::Alignment
This property holds the alignment of the progress bar
Access functions:
| Qt::Alignment | alignment() const |
| void | setAlignment(Qt::Alignment alignment) |
format : QString
This property holds the string used to generate the current text
%p - is replaced by the percentage completed. %v - is replaced by the current value. %m - is replaced by the total number of steps.
The default value is "%p%".
This property was introduced in Qt 4.2.
Access functions:
| QString | format() const |
| void | setFormat(const QString &format) |
| void | resetFormat() |
See also text().
invertedAppearance : bool
This property holds whether or not a progress bar shows its progress inverted
If this property is true, the progress bar grows in the other direction (e.g. from right to left). By default, the progress bar is not inverted.
This property was introduced in Qt 4.1.
Access functions:
| bool | invertedAppearance() const |
| void | setInvertedAppearance(bool invert) |
See also orientation and layoutDirection.
maximum : int
This property holds the progress bar's maximum value
When setting this property, the minimum is adjusted if necessary to ensure that the range remains valid. If the current value falls outside the new range, the progress bar is reset with reset().
Access functions:
| int | maximum() const |
| void | setMaximum(int maximum) |
minimum : int
This property holds the progress bar's minimum value
When setting this property, the maximum is adjusted if necessary to ensure that the range remains valid. If the current value falls outside the new range, the progress bar is reset with reset().
Access functions:
| int | minimum() const |
| void | setMinimum(int minimum) |
orientation : Qt::Orientation
This property holds the orientation of the progress bar
The orientation must be Qt::Horizontal (the default) or Qt::Vertical.
This property was introduced in Qt 4.1.
Access functions:
| Qt::Orientation | orientation() const |
| void | setOrientation(Qt::Orientation) |
See also invertedAppearance and textDirection.
text : const QString
This property holds the descriptive text shown with the progress bar
The text returned is the same as the text displayed in the center (or in some styles, to the left) of the progress bar.
The progress shown in the text may be smaller than the minimum value, indicating that the progress bar is in the "reset" state before any progress is set.
In the default implementation, the text either contains a percentage value that indicates the progress so far, or it is blank because the progress bar is in the reset state.
Access functions:
| virtual QString | text() const |
textDirection : Direction
This property holds the reading direction of the text for vertical progress bars
This property has no impact on horizontal progress bars. By default, the reading direction is QProgressBar::TopToBottom.
This property was introduced in Qt 4.1.
Access functions:
| QProgressBar::Direction | textDirection() const |
| void | setTextDirection(QProgressBar::Direction textDirection) |
See also orientation and textVisible.
textVisible : bool
This property holds whether the current completed percentage should be displayed
This property may be ignored by the style (e.g., QMacStyle never draws the text).
Access functions:
| bool | isTextVisible() const |
| void | setTextVisible(bool visible) |
See also textDirection.
value : int
This property holds the progress bar's current value
Attempting to change the current value to one outside the minimum-maximum range has no effect on the current value.
Access functions:
| int | value() const |
| void | setValue(int value) |
Notifier signal:
| void | valueChanged(int value) |
Member Function Documentation
QProgressBar::QProgressBar(QWidget *parent = nullptr)
Constructs a progress bar with the given parent.
By default, the minimum step value is set to 0, and the maximum to 100.
See also setRange().
[slot] void QProgressBar::reset()
Reset the progress bar. The progress bar "rewinds" and shows no progress.
[slot] void QProgressBar::setRange(int minimum, int maximum)
Sets the progress bar's minimum and maximum values to minimum and maximum respectively.
If maximum is smaller than minimum, minimum becomes the only legal value.
If the current value falls outside the new range, the progress bar is reset with reset().
The QProgressBar can be set to undetermined state by using setRange(0, 0).
[signal] void QProgressBar::valueChanged(int value)
This signal is emitted when the value shown in the progress bar changes. value is the new value shown by the progress bar.
Note: Notifier signal for property value.
[virtual] QProgressBar::~QProgressBar()
Destructor.
[override virtual protected] bool QProgressBar::event(QEvent *e)
Reimplements: QWidget::event(QEvent *event).
[protected] void QProgressBar::initStyleOption(QStyleOptionProgressBar *option) const
Initialize option with the values from this QProgressBar. This method is useful for subclasses when they need a QStyleOptionProgressBar, but don't want to fill in all the information themselves.
See also QStyleOption::initFrom().
[override virtual] QSize QProgressBar::minimumSizeHint() const
Reimplements an access function for property: QWidget::minimumSizeHint.
[override virtual protected] void QProgressBar::paintEvent(QPaintEvent *)
Reimplements: QWidget::paintEvent(QPaintEvent *event).
[override virtual] QSize QProgressBar::sizeHint() const
Reimplements an access function for property: QWidget::sizeHint.