ListView.model 不能正常工作 [英] ListView.model does not work well
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问题描述
在下面的代码中，我有一个 ListView，我用 JSON 数据提供它.我使用 parse 函数来提取数据并将其分配给模型，即:
view.model = JSON.parse(io.text)但是，似乎 view.model 没有获取数据，因此我的应用程序无法显示任何内容.
这是我的完整代码.
导入QtQuick 2.0导入 FilesIO 1.0导入 QtQuick.Window 2.2导入 QtQuick.Controls 1.3导入 QtQml 2.2应用程序窗口{身份证:根宽度:320高度:410标题:LOLLLL"白颜色"可见:真实属性字符串 currentStockId: ""属性字符串 currentStockName: ""函数读取文档(){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()文件IO{id:io}列表显示 {编号:查看anchors.fill:父级宽度:parent.width剪辑:真实keyNavigationWraps: 真高亮移动持续时间:0焦点:真实snapMode:ListView.SnapToItem/* 模型:列表模型 {编号:股票//数据来自:http://en.wikipedia.org/wiki/NASDAQ-100ListElement {名称:苹果公司"；stockId:苹果"；值:0.0"；改变:0.0"；变化百分比:0.0"}ListElement {名称:Adobe Inc"；stockId: "ADBE";值:0.0"；改变:0.0"；变化百分比:0.0"}}*/onCurrentIndexChanged:{mainRect.listViewActive = 0;root.currentStockId = model.get(currentIndex).stockId;root.currentStockName = model.get(currentIndex).name;}委托:矩形{高度:102宽度:parent.width颜色:透明"鼠标区域{anchors.fill:父级；已点击:{view.currentIndex = 索引；}}文本 {id:stockIdTextanchors.top: parent.topanchors.topMargin: 15anchors.left: parent.left锚点.leftMargin:15宽度:125高度:40颜色:#000000"font.family: "Droid Sans Georgian"font.pointSize: 20font.weight: 字体粗体垂直对齐:Text.AlignVCenter文字:stockId}文本 {id:stockValueTextanchors.top: parent.topanchors.topMargin: 15anchors.right: parent.rightanchors.rightMargin: 0.31 * parent.width宽度:190高度:40颜色:#000000"font.family: "Droid Sans Ethiopic"font.pointSize: 20font.bold: 真水平对齐:Text.AlignRight垂直对齐:Text.AlignVCenter文本:值Component.onCompleted: view.getCloseValue(index);}文本 {id:stockValueChangeTextanchors.top: parent.topanchors.topMargin: 15anchors.right: parent.rightanchors.rightMargin: 20宽度:135高度:40颜色:#328930"font.family: "Droid Sans Hebrew"font.pointSize: 20font.bold: 真水平对齐:Text.AlignRight垂直对齐:Text.AlignVCenter文字:改变onTextChanged:{如果(解析浮动(文本)> = 0.0)颜色 = "#328930";别的颜色 = "#d40000";}}文本 {id:股票名称文本anchors.top: stockIdText.bottomanchors.left: parent.left锚点.leftMargin:15宽度:330身高:30颜色:#000000"font.family:打开Sans"字体点大小:16font.bold: 假elide: Text.ElideRight最大行数:1垂直对齐:Text.AlignVCenter文字:姓名}文本 {id:stockValueChangePercentageTextanchors.top: stockIdText.bottomanchors.right: parent.rightanchors.rightMargin: 20宽度:120身高:30颜色:#328930"font.family:打开Sans"字体点大小:18font.bold: 假水平对齐:Text.AlignRight垂直对齐:Text.AlignVCenter文本:更改百分比onTextChanged:{如果(解析浮动(文本)> = 0.0)颜色 = "#328930";别的颜色 = "#d40000";}}长方形 {id: 结束行anchors.bottom: parent.bottomanchors.left: parent.left高度:1宽度:parent.width颜色:#d7d7d7"}}突出显示:矩形{宽度:parent.width颜色:#eeeeee"}}}这里是用作输入的 stoc.json.
解决方案
看Qt 文档 你可以阅读
<块引用>模型可以使用 ListModel、XmlListModel 或 VisualItemModel 在 QML 中直接创建，或者由 C++ 模型类提供.
因此，没有关于 JSON 数据.您应该将其转换为 ListModel 或提供任何其他合适的方法.
以下是如何实现转换的示例:
ListView {anchors.fill:父级模型:列表模型{id:列表模型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]);}}}委托:文本{文本:名称 + ", " + stockId + ", " + value + ", " + change + ", " + changepercentage}}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"
},
]
解决方案
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
}
}
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