- Qt 5.5
- Qt Quick
- Qt Quick Demo - Calqlatr
- Display.qml Example File
- Qt 5.5.1 Reference Documentation

# Display.qml Example File

demos/calqlatr/content/Display.qml

    /****************************************************************************
    **
    ** Copyright (C) 2015 The Qt Company Ltd.
    ** Contact: http://www.qt.io/licensing/
    **
    ** This file is part of the examples of the Qt Toolkit.
    **
    ** $QT_BEGIN_LICENSE:BSD$
    ** You may use this file under the terms of the BSD license as follows:
    **
    ** "Redistribution and use in source and binary forms, with or without
    ** modification, are permitted provided that the following conditions are
    ** met:
    **   * Redistributions of source code must retain the above copyright
    **     notice, this list of conditions and the following disclaimer.
    **   * Redistributions in binary form must reproduce the above copyright
    **     notice, this list of conditions and the following disclaimer in
    **     the documentation and/or other materials provided with the
    **     distribution.
    **   * Neither the name of The Qt Company Ltd nor the names of its
    **     contributors may be used to endorse or promote products derived
    **     from this software without specific prior written permission.
    **
    **
    ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
    ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
    ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
    ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
    ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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    ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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    ****************************************************************************/

    import QtQuick 2.0
    import QtQuick.Window 2.0

    Item {
        id: display
        property real fontSize: Math.floor(Screen.pixelDensity * 5.0)
        property bool enteringDigits: false
        property int maxDigits: (width / fontSize) + 1
        property string displayedOperand
        property string errorString: qsTr("ERROR")
        property bool isError: displayedOperand === errorString

        function displayOperator(operator)
        {
            listView.model.append({ "operator": operator, "operand": "" })
            enteringDigits = true
            listView.positionViewAtEnd()
        }

        function newLine(operator, operand)
        {
            displayedOperand = displayNumber(operand)
            listView.model.append({ "operator": operator, "operand": displayedOperand })
            enteringDigits = false
            listView.positionViewAtEnd()
        }

        function appendDigit(digit)
        {
            if (!enteringDigits)
                listView.model.append({ "operator": "", "operand": "" })
            var i = listView.model.count - 1;
            listView.model.get(i).operand = listView.model.get(i).operand + digit;
            enteringDigits = true
            listView.positionViewAtEnd()
        }

        function setDigit(digit)
        {
            var i = listView.model.count - 1;
            listView.model.get(i).operand = digit;
            listView.positionViewAtEnd()
        }

        function clear()
        {
            displayedOperand = ""
            if (enteringDigits) {
                var i = listView.model.count - 1
                if (i >= 0)
                    listView.model.remove(i)
                enteringDigits = false
            }
        }

        // Returns a string representation of a number that fits in
        // display.maxDigits characters, trying to keep as much precision
        // as possible. If the number cannot be displayed, returns an
        // error string.
        function displayNumber(num) {
            if (typeof(num) != "number")
                return errorString;

            var intNum = parseInt(num);
            var intLen = intNum.toString().length;

            // Do not count the minus sign as a digit
            var maxLen = num < 0 ? maxDigits + 1 : maxDigits;

            if (num.toString().length <= maxLen) {
                if (isFinite(num))
                    return num.toString();
                return errorString;
            }

            // Integer part of the number is too long - try
            // an exponential notation
            if (intNum == num || intLen > maxLen - 3) {
                var expVal = num.toExponential(maxDigits - 6).toString();
                if (expVal.length <= maxLen)
                    return expVal;
            }

            // Try a float presentation with fixed number of digits
            var floatStr = parseFloat(num).toFixed(maxDigits - intLen - 1).toString();
            if (floatStr.length <= maxLen)
                return floatStr;

            return errorString;
        }

        Item {
            id: theItem
            width: parent.width + 32
            height: parent.height

            Rectangle {
                id: rect
                x: 16
                color: "white"
                height: parent.height
                width: display.width - 16
            }
            Image {
                anchors.right: rect.left
                source: "images/paper-edge-left.png"
                height: parent.height
                fillMode: Image.TileVertically
            }
            Image {
                anchors.left: rect.right
                source: "images/paper-edge-right.png"
                height: parent.height
                fillMode: Image.TileVertically
            }

            Image {
                id: grip
                source: "images/paper-grip.png"
                anchors.horizontalCenter: parent.horizontalCenter
                anchors.bottom: parent.bottom
                anchors.bottomMargin: 20
            }

            ListView {
                id: listView
                x: 16; y: 30
                width: display.width
                height: display.height - 50 - y
                delegate: Item {
                    height: display.fontSize * 1.1
                    width: parent.width
                    Text {
                        id: operator
                        x: 6
                        font.pixelSize: display.fontSize
                        color: "#6da43d"
                        text: model.operator
                    }
                    Text {
                        id: operand
                        font.pixelSize: display.fontSize
                        anchors.right: parent.right
                        anchors.rightMargin: 22
                        text: model.operand
                    }
                }
                model: ListModel { }
            }

        }

    }