AutoScroller.qml Example File

basic/content/AutoScroller.qml

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  ** Copyright (C) 2016 The Qt Company Ltd.
  ** Contact: https://www.qt.io/licensing/
  **
  ** This file is part of the Qt Virtual Keyboard module of the Qt Toolkit.
  **
  ** $QT_BEGIN_LICENSE:GPL$
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  ** Alternatively, this file may be used under the terms of the GNU
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  import QtQuick 2.0
  import QtQuick.VirtualKeyboard 2.1

  Item {
      property var flickable
      readonly property var inputItem: InputContext.inputItem

      onInputItemChanged: delayedLoading.start()

      function ensureVisible(flickable) {
          if (!Qt.inputMethod.visible || !inputItem || !flickable || !flickable.visible/* || !flickable.interactive*/)
              return;

          var verticallyFlickable = (flickable.flickableDirection === Flickable.HorizontalAndVerticalFlick || flickable.flickableDirection === Flickable.VerticalFlick
                                     || (flickable.flickableDirection === Flickable.AutoFlickDirection && flickable.contentHeight > flickable.height))
          var horizontallyFlickable = (flickable.flickableDirection === Flickable.HorizontalAndVerticalFlick || flickable.flickableDirection === Flickable.HorizontalFlick
                                       || (flickable.flickableDirection === Flickable.AutoFlickDirection && flickable.contentWidth > flickable.width))

          if ((!verticallyFlickable && !horizontallyFlickable) || !inputItem.hasOwnProperty("cursorRectangle"))
              return

          var cursorRectangle = flickable.contentItem.mapFromItem(inputItem, inputItem.cursorRectangle.x, inputItem.cursorRectangle.y)

          if (verticallyFlickable) {
              var scrollMarginVertical = flickable.scrollMarginVertical ? flickable.scrollMarginVertical : 10
              if (flickable.contentY >= cursorRectangle.y - scrollMarginVertical) {
                  // The flickable is foo far down; move it up.
                  flickable.contentY = Math.max(0, cursorRectangle.y  - scrollMarginVertical)
              } else if (flickable.contentY + flickable.height <= cursorRectangle.y  + inputItem.cursorRectangle.height + scrollMarginVertical) {
                  // The flickable is foo far up; move it down.
                  flickable.contentY = Math.min(flickable.contentHeight - flickable.height, cursorRectangle.y + inputItem.cursorRectangle.height - flickable.height + scrollMarginVertical)
              }
          }
          if (horizontallyFlickable) {
              var scrollMarginHorizontal = flickable.scrollMarginHorizontal ? flickable.scrollMarginHorizontal : 10
              if (flickable.contentX >= cursorRectangle.x - scrollMarginHorizontal) {
                  // The flickable is foo far down; move it up.
                  flickable.contentX = Math.max(0, cursorRectangle.x - scrollMarginHorizontal)
              } else if (flickable.contentX + flickable.width <= cursorRectangle.x + inputItem.cursorRectangle.width + scrollMarginHorizontal) {
                  // The flickable is foo far up; move it down.
                  flickable.contentX = Math.min(flickable.contentWidth - flickable.width, cursorRectangle.x + inputItem.cursorRectangle.width - flickable.width + scrollMarginHorizontal)
              }
          }
      }
      Timer {
          id: delayedLoading
          interval: 10
          onTriggered: ensureVisible(flickable)
      }
      Connections {
          ignoreUnknownSignals: true
          target: Qt.inputMethod
          onKeyboardRectangleChanged: delayedLoading.start()
      }
      Connections {
          ignoreUnknownSignals: true
          target: inputItem
          enabled: inputItem && inputItem.activeFocus
          onCursorRectangleChanged: delayedLoading.start()
      }
  }