Qt 4.0: QProgressBar Class Reference

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# QProgressBar Class Reference
[QtGui module]

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

    #include <QProgressBar>

Inherits QWidget.

- List of all members, including inherited members

### Properties

alignment : Qt::Alignment maximum : int minimum : int | text : const QString textVisible : bool value : int

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

### Public Functions

- QProgressBar ( QWidget * parent = 0 )
- Qt::Alignment alignment () const
- bool isTextVisible () const
- int maximum () const
- int minimum () const
- void setAlignment ( Qt::Alignment alignment )
- void setRange ( int minimum, int maximum )
- void setTextVisible ( bool visible )
- virtual QString text () const
- int value () const

- 184 public functions inherited from QWidget
- 28 public functions inherited from QObject
- 10 public functions inherited from QPaintDevice

### Public Slots

- void reset ()
- void setMaximum ( int maximum )
- void setMinimum ( int minimum )
- void setValue ( int value )

- 17 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

### Additional Inherited Members

- 4 static public members inherited from QWidget
- 4 static public members inherited from QObject
- 39 protected functions inherited from QWidget
- 7 protected functions inherited from QObject

## Detailed Description

The QProgressBar widget provides a horizontal 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.

See also QProgressDialog and GUI Design Handbook: Progress Indicator.

## 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 )

### 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 )

### 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

### textVisible : bool

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

Access functions:

- bool isTextVisible () const
- void setTextVisible ( bool visible )

### value : int

This property holds the progressbar's current value.

Attemting to change the current value to one outside the minimum-maximum range has no effect 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.