Qt 4.3: QProgressBar Class Reference

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# QProgressBar Class Reference
[QtGui module]

The QProgressBar widget provides a horizontal or vertical progress bar. More...

     #include <QProgressBar>

Inherits QWidget.

- List of all members, including inherited members

### Public Types

- enum Direction { TopToBottom, BottomToTop }

### Properties

alignment : Qt::Alignment format : QString invertedAppearance : bool maximum : int minimum : int | orientation : Qt::Orientation text : const QString textDirection : Direction textVisible : bool value : int

- 56 properties inherited from QWidget
- 1 property inherited from QObject

### Public Functions

- QProgressBar ( QWidget * parent = 0 )
- Qt::Alignment alignment () const
- QString format () const
- bool invertedAppearance ()
- bool isTextVisible () const
- int maximum () const
- int minimum () const
- Qt::Orientation orientation () const
- 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 ()
- int value () const

- 201 public functions inherited from QWidget
- 29 public functions inherited from QObject
- 12 public functions inherited from QPaintDevice

### 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 )

- 19 public slots inherited from QWidget
- 1 public slot inherited from QObject

### Signals

- void valueChanged ( int value )

- 1 signal inherited from QWidget
- 1 signal inherited from QObject

### Protected Functions

- void initStyleOption ( QStyleOptionProgressBar * option ) const

- 38 protected functions inherited from QWidget
- 7 protected functions inherited from QObject
- 1 protected function inherited from QPaintDevice

### Additional Inherited Members

- 4 static public members inherited from QWidget
- 5 static public members inherited from QObject
- 1 protected slot inherited from QWidget

## Detailed Description

The QProgressBar widget provides a horizontal or vertical progress bar.

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 QFtp or QHttp to download items when they are unable to determine the size of the item being downloaded.

| A progress bar shown in the Macintosh widget style.
| A progress bar shown in the Windows XP widget style.
| A progress bar shown in the Plastique widget style.

See also QTimeLine, 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 CDE, CleanLooks, Motif, and Plastique draw the text. Mac, Windows and WindowsXP style do not.

This enum was introduced 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 )

See also text().

### invertedAppearance : bool

This property holds whether or not a progress bar shows its progress inverted.

If this property is false, 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 ()
- 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 ()
- void setTextDirection ( QProgressBar::Direction textDirection )

See also orientation and textVisible.

### textVisible : bool

This property holds whether the current completed percentage should be displayed.

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 )

## Member Function Documentation

### QProgressBar::QProgressBar ( QWidget * parent = 0 )

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().

### void QProgressBar::initStyleOption ( QStyleOptionProgressBar * option ) const `[protected]`

Initialize option with the values from this QProgressBar. This method is useful for subclasses when they need a QStyleOptionProgressBar or QStyleOptionProgressBarV2, but don't want to fill in all the information themselves. This function will check the version of the QStyleOptionProgressBar and fill in the additional values for a QStyleOptionProgressBarV2.

See also QStyleOption::initFrom().

### void QProgressBar::reset () `[slot]`

Reset the progress bar. The progress bar "rewinds" and shows no progress.

### void QProgressBar::setRange ( int minimum, int maximum ) `[slot]`

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().

See also minimum and maximum.

### void QProgressBar::valueChanged ( int value ) `[signal]`

This signal is emitted when the value shown in the progress bar changes. value is the new value shown by the progress bar.