QProgressDialog

The QProgressDialog class provides feedback on the progress of a slow operation. More

Inheritance diagram of PySide2.QtWidgets.QProgressDialog

Synopsis

Functions

Slots

Signals

Detailed Description

A progress dialog is used to give the user an indication of how long an operation is going to take, and to demonstrate that the application has not frozen. It can also give the user an opportunity to abort the operation.

A common problem with progress dialogs is that it is difficult to know when to use them; operations take different amounts of time on different hardware. QProgressDialog offers a solution to this problem: it estimates the time the operation will take (based on time for steps), and only shows itself if that estimate is beyond minimumDuration() (4 seconds by default).

Use setMinimum() and setMaximum() or the constructor to set the number of “steps” in the operation and call setValue() as the operation progresses. The number of steps can be chosen arbitrarily. It can be the number of files copied, the number of bytes received, the number of iterations through the main loop of your algorithm, or some other suitable unit. Progress starts at the value set by setMinimum() , and the progress dialog shows that the operation has finished when you call setValue() with the value set by setMaximum() as its argument.

The dialog automatically resets and hides itself at the end of the operation. Use setAutoReset() and setAutoClose() to change this behavior. Note that if you set a new maximum (using setMaximum() or setRange() ) that equals your current value() , the dialog will not close regardless.

There are two ways of using QProgressDialog : modal and modeless.

Compared to a modeless QProgressDialog , a modal QProgressDialog is simpler to use for the programmer. Do the operation in a loop, call setValue() at intervals, and check for cancellation with wasCanceled() . For example:

progress = QProgressDialog("Copying files...", "Abort Copy", 0, numFiles, self)
progress.setWindowModality(Qt.WindowModal)

for i in rang(numFiles):
    progress.setValue(i)

    if progress.wasCanceled():
        break
    #... copy one file

progress.setValue(numFiles)

A modeless progress dialog is suitable for operations that take place in the background, where the user is able to interact with the application. Such operations are typically based on QTimer (or timerEvent() ) or QSocketNotifier ; or performed in a separate thread. A QProgressBar in the status bar of your main window is often an alternative to a modeless progress dialog.

You need to have an event loop to be running, connect the canceled() signal to a slot that stops the operation, and call setValue() at intervals. For example:

# Operation constructor
def __init__(self, parent):
    QObject.__init__(self, parent)

    pd =  QProgressDialog("Operation in progress.", "Cancel", 0, 100)
    connect(pd, SIGNAL("canceled()"), self, SLOT("cancel()"))
    t =  QTimer(self)
    connect(t, SIGNAL("timeout()"), self, SLOT("perform()"))
    t.start(0)



def perform(self):

    pd.setValue(steps)
    #... perform one percent of the operation
    steps++
    if steps > pd.maximum():
        t.stop()



def cancel(self):

    t.stop()
    #... cleanup

In both modes the progress dialog may be customized by replacing the child widgets with custom widgets by using setLabel() , setBar() , and setCancelButton() . The functions setLabelText() and setCancelButtonText() set the texts shown.

../../_images/fusion-progressdialog.png

See also

QDialog QProgressBar GUI Design Handbook: Progress Indicator Find Files Example Pixelator Example

class QProgressDialog([parent=None[, flags=Qt.WindowFlags()]])

QProgressDialog(labelText, cancelButtonText, minimum, maximum[, parent=None[, flags=Qt.WindowFlags()]])

param parent

QWidget

param cancelButtonText

unicode

param flags

WindowFlags

param labelText

unicode

param minimum

int

param maximum

int

Constructs a progress dialog.

Default settings:

  • The label text is empty.

  • The cancel button text is (translated) “Cancel”.

  • minimum is 0;

  • maximum is 100

The parent argument is dialog’s parent widget. The widget flags, f , are passed to the QDialog() constructor.

Constructs a progress dialog.

The labelText is the text used to remind the user what is progressing.

The cancelButtonText is the text to display on the cancel button. If QString() is passed then no cancel button is shown.

The minimum and maximum is the number of steps in the operation for which this progress dialog shows progress. For example, if the operation is to examine 50 files, this value minimum value would be 0, and the maximum would be 50. Before examining the first file, call setValue (0). As each file is processed call setValue (1), setValue (2), etc., finally calling setValue (50) after examining the last file.

The parent argument is the dialog’s parent widget. The parent, parent , and widget flags, f , are passed to the QDialog() constructor.

PySide2.QtWidgets.QProgressDialog.autoClose()
Return type

bool

See also

setAutoClose()

PySide2.QtWidgets.QProgressDialog.autoReset()
Return type

bool

See also

setAutoReset()

PySide2.QtWidgets.QProgressDialog.cancel()

Resets the progress dialog. wasCanceled() becomes true until the progress dialog is reset. The progress dialog becomes hidden.

PySide2.QtWidgets.QProgressDialog.canceled()
PySide2.QtWidgets.QProgressDialog.forceShow()

Shows the dialog if it is still hidden after the algorithm has been started and minimumDuration milliseconds have passed.

PySide2.QtWidgets.QProgressDialog.labelText()
Return type

unicode

See also

setLabelText()

PySide2.QtWidgets.QProgressDialog.maximum()
Return type

int

See also

setMaximum()

PySide2.QtWidgets.QProgressDialog.minimum()
Return type

int

See also

setMinimum()

PySide2.QtWidgets.QProgressDialog.minimumDuration()
Return type

int

PySide2.QtWidgets.QProgressDialog.open(receiver, member)
Parameters
  • receiverQObject

  • member – str

Opens the dialog and connects its canceled() signal to the slot specified by receiver and member .

The signal will be disconnected from the slot when the dialog is closed.

PySide2.QtWidgets.QProgressDialog.reset()

Resets the progress dialog. The progress dialog becomes hidden if autoClose() is true.

PySide2.QtWidgets.QProgressDialog.setAutoClose(close)
Parameters

closebool

See also

autoClose()

PySide2.QtWidgets.QProgressDialog.setAutoReset(reset)
Parameters

resetbool

See also

autoReset()

PySide2.QtWidgets.QProgressDialog.setBar(bar)
Parameters

barQProgressBar

Sets the progress bar widget to bar . The progress dialog resizes to fit. The progress dialog takes ownership of the progress bar which will be deleted when necessary, so do not use a progress bar allocated on the stack.

PySide2.QtWidgets.QProgressDialog.setCancelButton(button)
Parameters

buttonQPushButton

Sets the cancel button to the push button, cancelButton . The progress dialog takes ownership of this button which will be deleted when necessary, so do not pass the address of an object that is on the stack, i.e. use new() to create the button. If None is passed, no cancel button will be shown.

PySide2.QtWidgets.QProgressDialog.setCancelButtonText(text)
Parameters

text – unicode

Sets the cancel button’s text to cancelButtonText . If the text is set to QString() then it will cause the cancel button to be hidden and deleted.

PySide2.QtWidgets.QProgressDialog.setLabel(label)
Parameters

labelQLabel

Sets the label to label . The progress dialog resizes to fit. The label becomes owned by the progress dialog and will be deleted when necessary, so do not pass the address of an object on the stack.

See also

setLabelText()

PySide2.QtWidgets.QProgressDialog.setLabelText(text)
Parameters

text – unicode

See also

labelText()

PySide2.QtWidgets.QProgressDialog.setMaximum(maximum)
Parameters

maximumint

See also

maximum()

PySide2.QtWidgets.QProgressDialog.setMinimum(minimum)
Parameters

minimumint

See also

minimum()

PySide2.QtWidgets.QProgressDialog.setMinimumDuration(ms)
Parameters

msint

PySide2.QtWidgets.QProgressDialog.setRange(minimum, maximum)
Parameters
  • minimumint

  • maximumint

Sets the progress dialog’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 dialog is reset with reset() .

See also

minimum maximum

PySide2.QtWidgets.QProgressDialog.setValue(progress)
Parameters

progressint

See also

value()

PySide2.QtWidgets.QProgressDialog.value()
Return type

int

See also

setValue()

PySide2.QtWidgets.QProgressDialog.wasCanceled()
Return type

bool