QProgressBar Class Reference
^{[QtGui module]}

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 minumum 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 QProgressDialog and GUI Design Handbook: Progress Indicator.

Member Type Documentation

enum QProgressBar::Direction

Specifies the reading direction of the text for vertical progress bars.

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 )

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 progressbar 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 progressbar 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::reset ()   [slot]

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

void QProgressBar::setRange ( int minimum, int maximum )

Sets the progressbar'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 progressbar 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.