com.trolltech.qt.gui
Class QProgressDialog

java.lang.Object
  extended by com.trolltech.qt.internal.QSignalEmitterInternal
      extended by com.trolltech.qt.QSignalEmitter
          extended by com.trolltech.qt.QtJambiObject
              extended by com.trolltech.qt.core.QObject
                  extended by com.trolltech.qt.gui.QWidget
                      extended by com.trolltech.qt.gui.QDialog
                          extended by com.trolltech.qt.gui.QProgressDialog
All Implemented Interfaces:
QPaintDeviceInterface, QtJambiInterface

public class QProgressDialog
extends QDialog

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

        QProgressDialog progress =
            new QProgressDialog("Copying files...", "Abort Copy", 0, numFiles, this);
        progress.setWindowModality(Qt.WindowModality.WindowModal);

        for (int i = 0; i < numFiles; i++) {
            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 QObject::timerEvent()), QSocketNotifier, or QUrlOperator; 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:

    // Operationructor
    public Operation(QObject parent)
    {
        super(parent);

        pd = new QProgressDialog("Operation in progress.", "Cancel", 0, 100);
        pd.canceled.connect(this, "cancel()");

        t = new QTimer(this);
        t.timeout.connect(this, "perform()");

        t.start(0);
    }
    
void perform() { pd.setValue(steps); //... perform one percent of the operation steps++; if (steps > pd.maximum()) t.stop(); }
void cancel() { 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.

See also:
QDialog, QProgressBar, GUI Design Handbook: Progress Indicator, Find Files Example, and Pixelator Example.


Nested Class Summary
 
Nested classes/interfaces inherited from class com.trolltech.qt.gui.QDialog
QDialog.DialogCode
 
Nested classes/interfaces inherited from class com.trolltech.qt.gui.QWidget
QWidget.RenderFlag, QWidget.RenderFlags
 
Nested classes/interfaces inherited from class com.trolltech.qt.QSignalEmitter
QSignalEmitter.AbstractSignal, QSignalEmitter.PrivateSignal0, QSignalEmitter.PrivateSignal1, QSignalEmitter.PrivateSignal2, QSignalEmitter.PrivateSignal3, QSignalEmitter.PrivateSignal4, QSignalEmitter.PrivateSignal5, QSignalEmitter.PrivateSignal6, QSignalEmitter.PrivateSignal7, QSignalEmitter.PrivateSignal8, QSignalEmitter.PrivateSignal9, QSignalEmitter.Signal0, QSignalEmitter.Signal1, QSignalEmitter.Signal2, QSignalEmitter.Signal3, QSignalEmitter.Signal4, QSignalEmitter.Signal5, QSignalEmitter.Signal6, QSignalEmitter.Signal7, QSignalEmitter.Signal8, QSignalEmitter.Signal9
 
Nested classes/interfaces inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
com.trolltech.qt.internal.QSignalEmitterInternal.AbstractSignalInternal
 
Field Summary
 QSignalEmitter.Signal0 canceled
          This signal is emitted when the cancel button is clicked.
 
Fields inherited from class com.trolltech.qt.gui.QDialog
accepted, finished, rejected
 
Fields inherited from class com.trolltech.qt.gui.QWidget
customContextMenuRequested
 
Fields inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
currentSender
 
Constructor Summary
QProgressDialog()
          Constructs a progress dialog.
QProgressDialog(QWidget parent)
          Constructs a progress dialog.
QProgressDialog(QWidget parent, Qt.WindowFlags flags)
          Constructs a progress dialog.
QProgressDialog(QWidget parent, Qt.WindowType[] flags)
          This is an overloaded method provided for convenience.
QProgressDialog(java.lang.String labelText, java.lang.String cancelButtonText, int minimum, int maximum)
          Constructs a progress dialog.
QProgressDialog(java.lang.String labelText, java.lang.String cancelButtonText, int minimum, int maximum, QWidget parent)
          Constructs a progress dialog.
QProgressDialog(java.lang.String labelText, java.lang.String cancelButtonText, int minimum, int maximum, QWidget parent, Qt.WindowFlags flags)
          Constructs a progress dialog.
QProgressDialog(java.lang.String labelText, java.lang.String cancelButtonText, int minimum, int maximum, QWidget parent, Qt.WindowType[] flags)
          This is an overloaded method provided for convenience.
 
Method Summary
 boolean autoClose()
          This property holds whether the dialog gets hidden by reset().
 boolean autoReset()
          This property holds whether the progress dialog calls reset() as soon as value() equals maximum().
 void cancel()
          Resets the progress dialog.
protected  void forceShow()
          Shows the dialog if it is still hidden after the algorithm has been started and minimumDuration milliseconds have passed.
 java.lang.String labelText()
          This property holds the label's text.
 int maximum()
          This property holds the highest value represented by the progress bar.
 int minimum()
          This property holds the lowest value represented by the progress bar.
 int minimumDuration()
          This property holds the time that must pass before the dialog appears.
 void reset()
          Resets the progress dialog.
 void setAutoClose(boolean close)
          This property holds whether the dialog gets hidden by reset().
 void setAutoReset(boolean reset)
          This property holds whether the progress dialog calls reset() as soon as value() equals maximum().
 void setBar(QProgressBar bar)
          Sets the progress bar widget to bar.
 void setCancelButton(QPushButton button)
          Sets the cancel button to the push button, cancelButton.
 void setCancelButtonText(java.lang.String text)
          Sets the cancel button's text to cancelButtonText.
 void setLabel(QLabel label)
          Sets the label to label.
 void setLabelText(java.lang.String text)
          This property holds the label's text.
 void setMaximum(int maximum)
          This property holds the highest value represented by the progress bar.
 void setMinimum(int minimum)
          This property holds the lowest value represented by the progress bar.
 void setMinimumDuration(int ms)
          This property holds the time that must pass before the dialog appears.
 void setRange(int minimum, int maximum)
          Sets the progress dialog's minimum and maximum values to minimum and maximum, respectively.
 void setValue(int progress)
          This property holds the current amount of progress made.
 int value()
          This property holds the current amount of progress made.
 boolean wasCanceled()
          This property holds whether the dialog was canceled.
 
Methods inherited from class com.trolltech.qt.gui.QDialog
accept, done, exec, isSizeGripEnabled, open, reject, result, setModal, setResult, setSizeGripEnabled
 
Methods inherited from class com.trolltech.qt.gui.QWidget
acceptDrops, accessibleDescription, accessibleName, actionEvent, actions, activateWindow, addAction, addActions, adjustSize, autoFillBackground, backgroundRole, baseSize, changeEvent, childAt, childAt, childrenRect, childrenRegion, clearFocus, clearMask, close, closeEvent, contentsRect, contextMenuEvent, contextMenuPolicy, cursor, depth, destroy, destroy, destroy, dragEnterEvent, dragLeaveEvent, dragMoveEvent, dropEvent, effectiveWinId, ensurePolished, enterEvent, focusInEvent, focusNextChild, focusNextPrevChild, focusOutEvent, focusPolicy, focusPreviousChild, focusProxy, focusWidget, font, fontInfo, fontMetrics, foregroundRole, frameGeometry, frameSize, geometry, getContentsMargins, grabKeyboard, grabMouse, grabMouse, grabShortcut, grabShortcut, graphicsProxyWidget, hasFocus, hasMouseTracking, height, heightForWidth, heightMM, hide, hideEvent, inputContext, inputMethodEvent, inputMethodQuery, insertAction, insertActions, isActiveWindow, isAncestorOf, isEnabled, isEnabledTo, isFullScreen, isHidden, isMaximized, isMinimized, isModal, isVisible, isVisibleTo, isWindow, isWindowModified, keyboardGrabber, keyPressEvent, keyReleaseEvent, languageChange, layout, layoutDirection, leaveEvent, locale, logicalDpiX, logicalDpiY, lower, mapFrom, mapFromGlobal, mapFromParent, mapTo, mapToGlobal, mapToParent, mask, maximumHeight, maximumSize, maximumWidth, metric, minimumHeight, minimumSize, minimumSizeHint, minimumWidth, mouseDoubleClickEvent, mouseGrabber, mouseMoveEvent, mousePressEvent, mouseReleaseEvent, move, move, moveEvent, nativeParentWidget, nextInFocusChain, normalGeometry, numColors, overrideWindowFlags, overrideWindowFlags, overrideWindowState, paintEngine, paintEvent, paintingActive, palette, parentWidget, physicalDpiX, physicalDpiY, pos, raise, rect, releaseKeyboard, releaseMouse, releaseShortcut, removeAction, render, render, render, render, render, render, render, render, render, repaint, repaint, repaint, repaint, resetInputContext, resize, resize, resizeEvent, restoreGeometry, saveGeometry, scroll, scroll, setAcceptDrops, setAccessibleDescription, setAccessibleName, setAttribute, setAttribute, setAutoFillBackground, setBackgroundRole, setBaseSize, setBaseSize, setContentsMargins, setContentsMargins, setContextMenuPolicy, setCursor, setDisabled, setEnabled, setFixedHeight, setFixedSize, setFixedSize, setFixedWidth, setFocus, setFocus, setFocusPolicy, setFocusProxy, setFont, setForegroundRole, setGeometry, setGeometry, setHidden, setInputContext, setLayout, setLayoutDirection, setLocale, setMask, setMask, setMaximumHeight, setMaximumSize, setMaximumSize, setMaximumWidth, setMinimumHeight, setMinimumSize, setMinimumSize, setMinimumWidth, setMouseTracking, setPalette, setParent, setParent, setParent, setShortcutAutoRepeat, setShortcutAutoRepeat, setShortcutEnabled, setShortcutEnabled, setSizeIncrement, setSizeIncrement, setSizePolicy, setSizePolicy, setStatusTip, setStyle, setStyleSheet, setTabOrder, setToolTip, setUpdatesEnabled, setVisible, setWhatsThis, setWindowFilePath, setWindowFlags, setWindowFlags, setWindowIcon, setWindowIconText, setWindowModality, setWindowModified, setWindowOpacity, setWindowRole, setWindowState, setWindowState, setWindowTitle, show, showEvent, showFullScreen, showMaximized, showMinimized, showNormal, size, sizeHint, sizeIncrement, sizePolicy, stackUnder, statusTip, style, styleSheet, tabletEvent, testAttribute, toolTip, underMouse, unsetCursor, unsetLayoutDirection, unsetLocale, update, update, update, update, updateGeometry, updateMicroFocus, updatesEnabled, visibleRegion, whatsThis, wheelEvent, width, widthMM, window, windowFilePath, windowFlags, windowIcon, windowIconText, windowModality, windowOpacity, windowRole, windowState, windowTitle, windowType, winId, x, y
 
Methods inherited from class com.trolltech.qt.core.QObject
childEvent, children, connectSlotsByName, customEvent, disposeLater, dumpObjectInfo, dumpObjectTree, dynamicPropertyNames, event, eventFilter, findChild, findChild, findChild, findChildren, findChildren, findChildren, findChildren, indexOfProperty, installEventFilter, isWidgetType, killTimer, moveToThread, objectName, parent, properties, property, removeEventFilter, setObjectName, setParent, setProperty, startTimer, timerEvent, toString, userProperty
 
Methods inherited from class com.trolltech.qt.QtJambiObject
dispose, disposed, equals, finalize, reassignNativeResources, tr, tr, tr
 
Methods inherited from class com.trolltech.qt.QSignalEmitter
blockSignals, disconnect, disconnect, signalsBlocked, signalSender, thread
 
Methods inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
__qt_signalInitialization
 
Methods inherited from class java.lang.Object
clone, getClass, hashCode, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface com.trolltech.qt.QtJambiInterface
disableGarbageCollection, nativeId, nativePointer, reenableGarbageCollection, setJavaOwnership
 

Field Detail

canceled

public final QSignalEmitter.Signal0 canceled
This signal is emitted when the cancel button is clicked. It is connected to the cancel() slot by default.

See also:
wasCanceled().

Constructor Detail

QProgressDialog

public QProgressDialog(QWidget parent,
                       Qt.WindowType[] flags)
This is an overloaded method provided for convenience.


QProgressDialog

public QProgressDialog(QWidget parent)
Constructs a progress dialog.

Default settings:

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

See also:
setLabelText(), setCancelButtonText(), setCancelButton(), setMinimum(), and setMaximum().


QProgressDialog

public QProgressDialog()
Constructs a progress dialog.

Default settings:

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

See also:
setLabelText(), setCancelButtonText(), setCancelButton(), setMinimum(), and setMaximum().


QProgressDialog

public QProgressDialog(QWidget parent,
                       Qt.WindowFlags flags)
Constructs a progress dialog.

Default settings:

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

See also:
setLabelText(), setCancelButtonText(), setCancelButton(), setMinimum(), and setMaximum().


QProgressDialog

public QProgressDialog(java.lang.String labelText,
                       java.lang.String cancelButtonText,
                       int minimum,
                       int maximum,
                       QWidget parent,
                       Qt.WindowType[] flags)
This is an overloaded method provided for convenience.


QProgressDialog

public QProgressDialog(java.lang.String labelText,
                       java.lang.String cancelButtonText,
                       int minimum,
                       int maximum,
                       QWidget parent)
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, or 0 if no cancel button is to be 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::QDialog() constructor.

See also:
setLabelText(), setLabel(), setCancelButtonText(), setCancelButton(), setMinimum(), and setMaximum().


QProgressDialog

public QProgressDialog(java.lang.String labelText,
                       java.lang.String cancelButtonText,
                       int minimum,
                       int maximum)
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, or 0 if no cancel button is to be 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::QDialog() constructor.

See also:
setLabelText(), setLabel(), setCancelButtonText(), setCancelButton(), setMinimum(), and setMaximum().


QProgressDialog

public QProgressDialog(java.lang.String labelText,
                       java.lang.String cancelButtonText,
                       int minimum,
                       int maximum,
                       QWidget parent,
                       Qt.WindowFlags flags)
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, or 0 if no cancel button is to be 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::QDialog() constructor.

See also:
setLabelText(), setLabel(), setCancelButtonText(), setCancelButton(), setMinimum(), and setMaximum().

Method Detail

autoClose

public final boolean autoClose()
This property holds whether the dialog gets hidden by reset(). The default is true.

See also:
setAutoReset().


autoReset

public final boolean autoReset()
This property holds whether the progress dialog calls reset() as soon as value() equals maximum(). The default is true.

See also:
setAutoClose().


cancel

public final void cancel()
Resets the progress dialog. wasCanceled() becomes true until the progress dialog is reset. The progress dialog becomes hidden.


forceShow

protected final void forceShow()
Shows the dialog if it is still hidden after the algorithm has been started and minimumDuration milliseconds have passed.

See also:
setMinimumDuration().


labelText

public final java.lang.String labelText()
This property holds the label's text. The default text is an empty string.


maximum

public final int maximum()
This property holds the highest value represented by the progress bar. The default is 0.

See also:
minimum, and setRange().


minimum

public final int minimum()
This property holds the lowest value represented by the progress bar. The default is 0.

See also:
maximum, and setRange().


minimumDuration

public final int minimumDuration()
This property holds the time that must pass before the dialog appears. If the expected duration of the task is less than the minimumDuration, the dialog will not appear at all. This prevents the dialog popping up for tasks that are quickly over. For tasks that are expected to exceed the minimumDuration, the dialog will pop up after the minimumDuration time or as soon as any progress is set.

If set to 0, the dialog is always shown as soon as any progress is set. The default is 4000 milliseconds.


reset

public final void reset()
Resets the progress dialog. The progress dialog becomes hidden if autoClose() is true.

See also:
setAutoClose(), and setAutoReset().


setAutoClose

public final void setAutoClose(boolean close)
This property holds whether the dialog gets hidden by reset(). The default is true.

See also:
setAutoReset().


setAutoReset

public final void setAutoReset(boolean reset)
This property holds whether the progress dialog calls reset() as soon as value() equals maximum(). The default is true.

See also:
setAutoClose().


setBar

public final void setBar(QProgressBar bar)
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.


setCancelButton

public final void setCancelButton(QPushButton button)
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.

See also:
setCancelButtonText().


setCancelButtonText

public final void setCancelButtonText(java.lang.String text)
Sets the cancel button's text to cancelButtonText.

See also:
setCancelButton().


setLabel

public final void setLabel(QLabel label)
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().


setLabelText

public final void setLabelText(java.lang.String text)
This property holds the label's text. The default text is an empty string.


setMaximum

public final void setMaximum(int maximum)
This property holds the highest value represented by the progress bar. The default is 0.

See also:
minimum, and setRange().


setMinimum

public final void setMinimum(int minimum)
This property holds the lowest value represented by the progress bar. The default is 0.

See also:
maximum, and setRange().


setMinimumDuration

public final void setMinimumDuration(int ms)
This property holds the time that must pass before the dialog appears. If the expected duration of the task is less than the minimumDuration, the dialog will not appear at all. This prevents the dialog popping up for tasks that are quickly over. For tasks that are expected to exceed the minimumDuration, the dialog will pop up after the minimumDuration time or as soon as any progress is set.

If set to 0, the dialog is always shown as soon as any progress is set. The default is 4000 milliseconds.


setRange

public final void setRange(int minimum,
                           int maximum)
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, and maximum.


setValue

public final void setValue(int progress)
This property holds the current amount of progress made. For the progress dialog to work as expected, you should initially set this property to 0 and finally set it to QProgressDialog::maximum(); you can call setValue() any number of times in-between.

Warning: If the progress dialog is modal (see QProgressDialog::QProgressDialog()), this function calls QApplication::processEvents(), so take care that this does not cause undesirable re-entrancy in your code. For example, don't use a QProgressDialog inside a paintEvent()!

See also:
minimum, and maximum.


value

public final int value()
This property holds the current amount of progress made. For the progress dialog to work as expected, you should initially set this property to 0 and finally set it to QProgressDialog::maximum(); you can call setValue() any number of times in-between.

Warning: If the progress dialog is modal (see QProgressDialog::QProgressDialog()), this function calls QApplication::processEvents(), so take care that this does not cause undesirable re-entrancy in your code. For example, don't use a QProgressDialog inside a paintEvent()!

See also:
minimum, and maximum.


wasCanceled

public final boolean wasCanceled()
This property holds whether the dialog was canceled.