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## com.trolltech.qt.gui
Class QScrollArea

    java.lang.Object
      com.trolltech.qt.internal.QSignalEmitterInternal
          com.trolltech.qt.QSignalEmitter
              com.trolltech.qt.QtJambiObject
                  com.trolltech.qt.core.QObject
                      com.trolltech.qt.gui.QWidget
                          com.trolltech.qt.gui.QFrame
                              com.trolltech.qt.gui.QAbstractScrollArea
                                  com.trolltech.qt.gui.QScrollArea

All Implemented Interfaces:
  QPaintDeviceInterface, QtJambiInterface

    public class QScrollArea

extends QAbstractScrollArea

The QScrollArea class provides a scrolling view onto another widget. A scroll area is used to display the contents of a child widget within a frame. If the widget exceeds the size of the frame, the view can provide scroll bars so that the entire area of the child widget can be viewed. The child widget must be specified with `setWidget()`. For example:

            QLabel imageLabel = new QLabel();
            QImage image = new QImage("happyguy.png");
            imageLabel.setPixmap(QPixmap.fromImage(image));

            QScrollArea scrollArea = new QScrollArea();
            scrollArea.setBackgroundRole(QPalette.ColorRole.Dark);
            scrollArea.setWidget(imageLabel);

The code above creates a scroll area (shown in the images below) containing an image label. When scaling the image, the scroll area can provide the necessary scroll bars:

The scroll bars appearance depends on the currently set `scroll bar policies` . You can control the appearance of the scroll bars using the inherited functionality from `QAbstractScrollArea`.

For example, you can set the `QAbstractScrollArea::horizontalScrollBarPolicy` and `QAbstractScrollArea::verticalScrollBarPolicy` properties. Or if you want the scroll bars to adjust dynamically when the contents of the scroll area changes, you can use the `horizontalScrollBar()` and `verticalScrollBar()` functions (which enable you to access the scroll bars) and set the scroll bars' values whenever the scroll area's contents change, using the QScrollBar::setValue() function.

You can retrieve the child widget using the `widget()` function. The view can be made to be resizable with the `setWidgetResizable()` function. The alignment of the widget can be specified with `setAlignment()`.

Two convenience functions `ensureVisible()` and `ensureWidgetVisible()` ensure a certain region of the contents is visible inside the viewport, by scrolling the contents if necessary.

## Size Hints and Layouts

When using a scroll area to display the contents of a custom widget, it is important to ensure that the `size hint` of the child widget is set to a suitable value. If a standard `QWidget` is used for the child widget, it may be necessary to call `QWidget::setMinimumSize()` to ensure that the contents of the widget are shown correctly within the scroll area.

If a scroll area is used to display the contents of a widget that contains child widgets arranged in a layout, it is important to realise that the size policy of the layout will also determine the size of the widget. This is especially useful to know if you intend to dynamically change the contents of the layout. In such cases, setting the layout's `size constraint` property to one which provides constraints on the minimum and/or maximum size of the layout (e.g., `QLayout::SetMinAndMaxSize` ) will cause the size of the the scroll area to be updated whenever the contents of the layout changes.

For a complete example using the QScrollArea class, see the Image Viewer example. The example shows how to combine `QLabel` and QScrollArea to display an image.

See also:
  `QAbstractScrollArea`, `QScrollBar`, and Image Viewer Example.

Nested Class Summary

Nested classes/interfaces inherited from class com.trolltech.qt.gui.QFrame
`QFrame.Shadow, QFrame.Shape, QFrame.StyleMask`

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.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

Fields inherited from class com.trolltech.qt.gui.QWidget
`customContextMenuRequested`

Fields inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
`currentSender`

Constructor Summary
`QScrollArea()` Constructs an empty scroll area with the given `parent`.
`QScrollArea(QWidget parent)` Constructs an empty scroll area with the given `parent`.

Method Summary
`Qt.Alignment` | `alignment()` This property holds the alignment of the scroll area's widget.
`void` | `ensureVisible(int x, int y)` Scrolls the contents of the scroll area so that the point (`x`, `y`) is visible inside the region of the viewport with margins specified in pixels by `xmargin` and `ymargin`.
`void` | `ensureVisible(int x, int y, int xmargin)` Scrolls the contents of the scroll area so that the point (`x`, `y`) is visible inside the region of the viewport with margins specified in pixels by `xmargin` and `ymargin`.
`void` | `ensureVisible(int x, int y, int xmargin, int ymargin)` Scrolls the contents of the scroll area so that the point (`x`, `y`) is visible inside the region of the viewport with margins specified in pixels by `xmargin` and `ymargin`.
`void` | `ensureWidgetVisible(QWidget childWidget)` Scrolls the contents of the scroll area so that the `childWidget` of `QScrollArea::widget()` is visible inside the viewport with margins specified in pixels by `xmargin` and `ymargin`.
`void` | `ensureWidgetVisible(QWidget childWidget, int xmargin)` Scrolls the contents of the scroll area so that the `childWidget` of `QScrollArea::widget()` is visible inside the viewport with margins specified in pixels by `xmargin` and `ymargin`.
`void` | `ensureWidgetVisible(QWidget childWidget, int xmargin, int ymargin)` Scrolls the contents of the scroll area so that the `childWidget` of `QScrollArea::widget()` is visible inside the viewport with margins specified in pixels by `xmargin` and `ymargin`.
`void` | `setAlignment(Qt.Alignment arg__1)` This property holds the alignment of the scroll area's widget.
`void` | `setAlignment(Qt.AlignmentFlag[] arg__1)`
`void` | `setWidget(QWidget widget)` Sets the scroll area's `widget`.
`void` | `setWidgetResizable(boolean resizable)` This property holds whether the scroll area should resize the view widget.
`QWidget` | `takeWidget()` Removes the scroll area's widget, and passes ownership of the widget to the caller.
`QWidget` | `widget()` Returns the scroll area's widget, or 0 if there is none.
`boolean` | `widgetResizable()` This property holds whether the scroll area should resize the view widget.

Methods inherited from class com.trolltech.qt.gui.QAbstractScrollArea
`addScrollBarWidget, addScrollBarWidget, cornerWidget, horizontalScrollBar, horizontalScrollBarPolicy, maximumViewportSize, scrollBarWidgets, scrollBarWidgets, scrollContentsBy, setCornerWidget, setHorizontalScrollBar, setHorizontalScrollBarPolicy, setupViewport, setVerticalScrollBar, setVerticalScrollBarPolicy, setViewport, setViewportMargins, verticalScrollBar, verticalScrollBarPolicy, viewport, viewportEvent`

Methods inherited from class com.trolltech.qt.gui.QFrame
`frameRect, frameShadow, frameShape, frameStyle, frameWidth, lineWidth, midLineWidth, setFrameRect, setFrameShadow, setFrameShape, setFrameStyle, setLineWidth, setMidLineWidth`

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, 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`

Constructor Detail

### QScrollArea

    public QScrollArea()

  Constructs an empty scroll area with the given `parent`.

See also:
  `setWidget()`.

### QScrollArea

    public QScrollArea(QWidget parent)

  Constructs an empty scroll area with the given `parent`.

See also:
  `setWidget()`.

Method Detail

### alignment

    public final Qt.Alignment alignment()

  This property holds the alignment of the scroll area's widget. By default, the widget stays rooted to the top-left corner of the scroll area.

### ensureVisible

    public final void ensureVisible(int x,
                                    int y,
                                    int xmargin)

  Scrolls the contents of the scroll area so that the point (`x`, `y`) is visible inside the region of the viewport with margins specified in pixels by `xmargin` and `ymargin`. If the specified point cannot be reached, the contents are scrolled to the nearest valid position. The default value for both margins is 50 pixels.

### ensureVisible

    public final void ensureVisible(int x,
                                    int y)

  Scrolls the contents of the scroll area so that the point (`x`, `y`) is visible inside the region of the viewport with margins specified in pixels by `xmargin` and `ymargin`. If the specified point cannot be reached, the contents are scrolled to the nearest valid position. The default value for both margins is 50 pixels.

### ensureVisible

    public final void ensureVisible(int x,
                                    int y,
                                    int xmargin,
                                    int ymargin)

  Scrolls the contents of the scroll area so that the point (`x`, `y`) is visible inside the region of the viewport with margins specified in pixels by `xmargin` and `ymargin`. If the specified point cannot be reached, the contents are scrolled to the nearest valid position. The default value for both margins is 50 pixels.

### ensureWidgetVisible

    public final void ensureWidgetVisible(QWidget childWidget,
                                          int xmargin)

  Scrolls the contents of the scroll area so that the `childWidget` of `QScrollArea::widget()` is visible inside the viewport with margins specified in pixels by `xmargin` and `ymargin`. If the specified point cannot be reached, the contents are scrolled to the nearest valid position. The default value for both margins is 50 pixels.

### ensureWidgetVisible

    public final void ensureWidgetVisible(QWidget childWidget)

  Scrolls the contents of the scroll area so that the `childWidget` of `QScrollArea::widget()` is visible inside the viewport with margins specified in pixels by `xmargin` and `ymargin`. If the specified point cannot be reached, the contents are scrolled to the nearest valid position. The default value for both margins is 50 pixels.

### ensureWidgetVisible

    public final void ensureWidgetVisible(QWidget childWidget,
                                          int xmargin,
                                          int ymargin)

  Scrolls the contents of the scroll area so that the `childWidget` of `QScrollArea::widget()` is visible inside the viewport with margins specified in pixels by `xmargin` and `ymargin`. If the specified point cannot be reached, the contents are scrolled to the nearest valid position. The default value for both margins is 50 pixels.

### setAlignment

    public final void setAlignment(Qt.AlignmentFlag[] arg__1)

### setAlignment

    public final void setAlignment(Qt.Alignment arg__1)

  This property holds the alignment of the scroll area's widget. By default, the widget stays rooted to the top-left corner of the scroll area.

### setWidget

    public final void setWidget(QWidget widget)

  Sets the scroll area's `widget`.

  The `widget` becomes a child of the scroll area, and will be destroyed when the scroll area is deleted or when a new widget is set.

  The widget's `autoFillBackground` property will be set to `true`.

  If the scroll area is visible when the `widget` is added, you must `show()` it explicitly.

  Note that You must add the layout of `widget` before you call this function; if you add it later, the `widget` will not be visible - regardless of when you `show()` the scroll area. In this case, you can also not `show()` the `widget` later.

See also:
  `widget()`.

### setWidgetResizable

    public final void setWidgetResizable(boolean resizable)

  This property holds whether the scroll area should resize the view widget. If this property is set to false (the default), the scroll area honors the size of its widget. Regardless of this property, you can programmatically resize the widget using `widget()`->resize(), and the scroll area will automatically adjust itself to the new size.

  If this property is set to true, the scroll area will automatically resize the widget in order to avoid scroll bars where they can be avoided, or to take advantage of extra space.

### takeWidget

    public final QWidget takeWidget()

  Removes the scroll area's widget, and passes ownership of the widget to the caller.

See also:
  `widget()`.

### widget

    public final QWidget widget()

  Returns the scroll area's widget, or 0 if there is none.

See also:
  `setWidget()`.

### widgetResizable

    public final boolean widgetResizable()

  This property holds whether the scroll area should resize the view widget. If this property is set to false (the default), the scroll area honors the size of its widget. Regardless of this property, you can programmatically resize the widget using `widget()`->resize(), and the scroll area will automatically adjust itself to the new size.

  If this property is set to true, the scroll area will automatically resize the widget in order to avoid scroll bars where they can be avoided, or to take advantage of extra space.

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