TextArea does not automatically scroll

[Leon_2001]

Hello,

I have some problems with TextArea.
My goal is to program a Code Editor, but I have some problems adding Linenumbers next to the textArea.

This is my attempt:

Pane {
  RowLayout {
    anchors.fill: parent
    spacing: 0

    ColumnLayout {
      id: lineNumbers
      Repeater {
        id: lineNumberRepeater
        model: editor.lineCount
        Layout.fillHeight: true
        Text {
          text: index + 1
          color: 'lightgray'
          font.pointSize: editor.font.pointSize
        }
      }
    }

    Flickable {
      id: flickable
      Layout.fillHeight: true
      Layout.fillWidth: true
      TextArea.flickable: TextArea {
        id: editor
        focus: true
        persistentSelection: true
        selectByMouse: true
        textMargin: 10
        wrapMode: Text.WrapAtWordBoundaryOrAnywhere

        Keys.onPressed: {
          if(event.key === Qt.Key_PageUp)
            flickable.flick(0,  60*Math.sqrt(flickable.height))
          if(event.key === Qt.Key_PageDown)
            flickable.flick(0, -60*Math.sqrt(flickable.height))
        }
      }
      ScrollBar.vertical: ScrollBar { }
    }
  }
}

But there are two Problems:

1. It doesn't scroll up if I reach the last visible line and press enter (it does if I remove the line numbers). I guess that's because the ScrollView/ Flickable does only apply to the CodeEditor but not to the lineNumbers?
2. LineNumbers and Code in the TextArea are not one the same Hight. One Reason for this is that the TextArea has a margin, but even without it they aren't on the same hight (or if I apply a top margin/padding to the lineNumbers).

I am even not sure if this is the right way to achieve this ... using pane as a root element for example

It should be one Page of a SwipeView. Is there a better solution?

By the way, can anyone explain to me what the property clip is? I have some problems understanding what clipping is.

Greetings Leon

[shaan7]

This sort-of does what you wanted-

import QtQuick 2.10
import QtQuick.Window 2.10
import QtQuick.Layouts 1.3
import QtQuick.Controls 2.2

Window {
    visible: true
    width: 640
    height: 480
    title: qsTr("Hello World")

    Pane {
        anchors.fill: parent

        ScrollView {
            anchors.fill: parent

            RowLayout {
                spacing: 0
                width: parent.parent.width

                ColumnLayout {
                    id: lineNumbers

                    Repeater {
                        id: lineNumberRepeater
                        model: editor.lineCount
                        Layout.fillHeight: true

                        Text {
                            text: index + 1
                            color: 'lightgray'
                            font.pointSize: editor.font.pointSize
                        }
                    }
                }

                TextArea {
                    id: editor
                    Layout.fillWidth: true

                    focus: true
                    persistentSelection: true
                    selectByMouse: true
                    textMargin: 10
                    wrapMode: Text.WrapAtWordBoundaryOrAnywhere

                    Rectangle {
                        anchors.fill: parent
                        color: "red"
                        opacity: 0.1
                    }
                }
            }
        }
    }
}

[Leon_2001]

Doesn't solve things.

I can scroll now both, but that is not really what I want (at least not completely).

Actually, I wish, that the scrolling is done automatically. So if I am in the last visible line, the next should be added while the rest is scrolled up by one line.
In your solution, I have to scroll up manually to see the new lines.

Furthermore, it would also be awesome to don't miss the feature of flickable. If you have 1000 of lines of code you can go up to line one really fast by pressing and moving up. Kind of throwing the TextArea up/down.

[timday]

@Leon_2001 You realize you can control the region a Flickable is displaying by simply assigning to it's contentY property? (Or binding it to some suitable expression). You're not limited to flickable.flick to move it around from code.

[Leon_2001]

@timday I am not quite sure, what you mean by this. I am new to qml, examples help me a lot understanding all these things.

Anyways, I figured out a working solution. The only thing I maybe could think about, how to use flicking not only in the column but also in the editor itself. At the moment, it isn't possible, because the editor has the focus (which he needs for things like marking text)

Pane {
  Item {
    id: editorItem
    anchors.fill: parent

    Flickable {
      id: flickable
      anchors.fill: parent
      flickableDirection: Flickable.VerticalFlick
      contentWidth: parent.width
      contentHeight: editor.height

      ColumnLayout {
        id: lineNumber
        spacing: 0
        Repeater {
          id: lineNumberRepeater
          model: editor.lineCount
          Text {
            text: index + 1
            color: 'lightgray'
            font.pointSize: editor.font.pointSize
          }
        }
      }
      TextArea.flickable: TextArea {
        id: editor
        anchors.left: lineNumber.right
        topPadding: 0
        leftPadding: 20
        rightPadding: 20
        bottomPadding: 0
        background: Rectangle {
           color: "transparent"
           border.color: "transparent"
        }
        font.pointSize: 18
        persistentSelection: true
        selectByMouse: true
        wrapMode: Text.WrapAtWordBoundaryOrAnywhere

        Keys.onPressed: {
          if(event.key === Qt.Key_PageUp)
            flickable.flick(0,  60*Math.sqrt(flickable.height))
          if(event.key === Qt.Key_PageDown)
            flickable.flick(0, -60*Math.sqrt(flickable.height))
        }
      }
      ScrollBar.vertical: ScrollBar { }
    }
    Documenthandler {
      id: documenthandler
      document: editor.textDocument
      cursorPosition: editor.cursorPosition
      selectionStart: editor.selectionStart
      selectionEnd: editor.selectionEnd
    }
  }
}

The solution is simply to put everything in the Flickable and to avoid nesting the TextArea into a RowLayout because TextArea.flickable: TextArea {} won't be working. Instead, I use anchors for the layout.

Would be interested if there is a solution for the nesting

Flickable {
  RowLayout {
    ColumnLayout {
    }
    TextArea.flickable: TextArea { //not possible
    }
  }
}

I have seen in the Documentation that it is sometimes possible to write down, that TextArea is nested -> Something Like TextArea.flickable: RowLayout.TextArea ... don't know