ListView.model does not work well

问题

In the following code I have a ListView which I feed with JSON data. I use the parse function to extract data and assign it to the model, i.e. :

view.model = JSON.parse(io.text)  

However, it seems that view.model don't get the data so that my application can't show anything.

Here is my full code.

import QtQuick 2.0
import FilesIO 1.0
import QtQuick.Window 2.2
import QtQuick.Controls 1.3
import QtQml 2.2

ApplicationWindow{
    id: root
    width: 320
    height: 410
    title:"LOLLLLL"
    color: "white"
    visible: true
    property string currentStockId: ""
    property string currentStockName: ""
    function readDocument(){
        io.source =Qt.resolvedUrl( "/home/yuhongsong/Qt/Examples/Qt-5.4/quick/demos/stocqt/content/stoc.json");
        io.read();
        view.model=JSON.parse(io.text);
    }
    Component.onCompleted: readDocument()
    FileIO{
        id:io
    }
    
    
    ListView {
        id: view
        anchors.fill: parent
        width: parent.width
        clip: true
        keyNavigationWraps: true
        highlightMoveDuration: 0
        focus: true
        snapMode: ListView.SnapToItem
        /*    model:ListModel {
              id: stocks
              // Data from : http://en.wikipedia.org/wiki/NASDAQ-100
             ListElement {name: "Apple Inc."; stockId: "AAPL"; value: "0.0"; change: "0.0"; changePercentage: "0.0"}
              ListElement {name: "Adobe Inc"; stockId: "ADBE"; value: "0.0"; change: "0.0"; changePercentage: "0.0"}
    }
    */
        
        onCurrentIndexChanged: {
            mainRect.listViewActive = 0;
            root.currentStockId = model.get(currentIndex).stockId;
            root.currentStockName = model.get(currentIndex).name;
        }
        
        delegate: Rectangle {
            height: 102
            width: parent.width
            color: "transparent"
            MouseArea {
                anchors.fill: parent;
                onClicked: {
                    view.currentIndex = index;
                }
            }
            
            Text {
                id: stockIdText
                anchors.top: parent.top
                anchors.topMargin: 15
                anchors.left: parent.left
                anchors.leftMargin: 15
                width: 125
                height: 40
                color: "#000000"
                font.family: "Droid Sans Georgian"
                font.pointSize: 20
                font.weight: Font.Bold
                verticalAlignment: Text.AlignVCenter
                text: stockId
            }
            
            Text {
                id: stockValueText
                anchors.top: parent.top
                anchors.topMargin: 15
                anchors.right: parent.right
                anchors.rightMargin: 0.31 * parent.width
                width: 190
                height: 40
                color: "#000000"
                font.family: "Droid Sans Ethiopic"
                font.pointSize: 20
                font.bold: true
                horizontalAlignment: Text.AlignRight
                verticalAlignment: Text.AlignVCenter
                text: value
                Component.onCompleted: view.getCloseValue(index);
            }
            
            Text {
                id: stockValueChangeText
                anchors.top: parent.top
                anchors.topMargin: 15
                anchors.right: parent.right
                anchors.rightMargin: 20
                width: 135
                height: 40
                color: "#328930"
                font.family: "Droid Sans Hebrew"
                font.pointSize: 20
                font.bold: true
                horizontalAlignment: Text.AlignRight
                verticalAlignment: Text.AlignVCenter
                text: change
                onTextChanged: {
                    if (parseFloat(text) >= 0.0)
                        color = "#328930";
                    else
                        color = "#d40000";
                }
            }
            
            Text {
                id: stockNameText
                anchors.top: stockIdText.bottom
                anchors.left: parent.left
                anchors.leftMargin: 15
                width: 330
                height: 30
                color: "#000000"
                font.family: "Open Sans"
                font.pointSize: 16
                font.bold: false
                elide: Text.ElideRight
                maximumLineCount: 1
                verticalAlignment: Text.AlignVCenter
                text: name
            }
            
            Text {
                id: stockValueChangePercentageText
                anchors.top: stockIdText.bottom
                anchors.right: parent.right
                anchors.rightMargin: 20
                width: 120
                height: 30
                color: "#328930"
                font.family: "Open Sans"
                font.pointSize: 18
                font.bold: false
                horizontalAlignment: Text.AlignRight
                verticalAlignment: Text.AlignVCenter
                text: changePercentage
                onTextChanged: {
                    if (parseFloat(text) >= 0.0)
                        color = "#328930";
                    else
                        color = "#d40000";
                }
            }
            
            Rectangle {
                id: endingLine
                anchors.bottom: parent.bottom
                anchors.left: parent.left
                height: 1
                width: parent.width
                color: "#d7d7d7"
            }
        }
        
        highlight: Rectangle {
            width: parent.width
            color: "#eeeeee"
        }
    }
    
}

And here is the stoc.json used as input.

[
   {
      "name": "Apple Inc",
      "stockId":"AAPL",
      "value":"0.0",
      "change":"0.0",
      "changepercentage":"0.0"
    },
    {
      "name": "Adobe Inc",
      "stockId":"ADBE",
      "value":"0.0",
      "change":"0.0",
      "changepercentage":"0.0"
    },
    {
      "name": "Analog Devices Inc",
      "stockId":"ADI",
      "value":"0.0",
      "change":"0.0",
      "changepercentage":"0.0"
    },
    {
      "name": "Automatic Data Processing Inc",
      "stockId":"ADP",
      "value":"0.0",
      "change":"0.0",
      "changepercentage":"0.0"
    },
]

回答1:

Looking at the Qt docs you can read that

Models can be created directly in QML using ListModel, XmlListModel or VisualItemModel, or provided by C++ model classes.

Hence, there is nothing about JSON data. You should either convert it to ListModel or provide any another suitable method.

Here is an example on how conversion can be realised:

ListView {
    anchors.fill: parent
    model: ListModel {
        id: listModel
        Component.onCompleted: {
            var data = [{ "name": "Apple Inc", "stockId":"AAPL", "value":"0.0", "change":"0.0", "changepercentage":"0.0" }, { "name": "Adobe Inc", "stockId":"ADBE", "value":"0.0", "change":"0.0", "changepercentage":"0.0" }, { "name": "Analog Devices Inc", "stockId":"ADI", "value":"0.0", "change":"0.0", "changepercentage":"0.0" }, { "name": "Automatic Data Processing Inc", "stockId":"ADP", "value":"0.0", "change":"0.0", "changepercentage":"0.0" }]
            for(var i = 0;i < data.length;i ++) {
                listModel.append(data[i]);
            }
        }
    }
    delegate: Text {
        text: name + ", " + stockId + ", " + value + ", " + change + ", " + changepercentage
    }
}

来源：https://stackoverflow.com/questions/32752532/listview-model-does-not-work-well