我正在使用 Blackberry 10 Cascades、QML 和 C++ QT，我正在尝试从我编写的一个小型 php web 服务中获取一些 XML 数据，以加载到我正在使用的 Blackberry 10 Dev Alpha Simulator 的列表中 - 但它是不工作。
那就是xml数据没有加载到QML文档的ListView中，显示在黑莓模拟器的屏幕上。我需要帮助才能完成这项工作。
我从一个涉及常规 http 请求的示例开始，并对其进行了修改以使其适合我的目的（这是一个 http post 请求）。（此代码在文本字段中获取世代编号 (1-5)）并打印出该世代的口袋妖怪游戏颜色列表）。
这是我开始使用的 QML 文件：
import bb.cascades 1.0
TabbedPane {
activePane: Page {
actions: [
// An action item that calls the C++ function that retrieves
// the contact list
ActionItem {
title: "Refresh"
onTriggered: app.initiateRequest()
}
]
content: Container {
layout: DockLayout {}
// A list that has two list item components, one for a header
// and one for contact names. The list has an object name so
// that we can set the data model from C++.
ListView {
objectName: "list"
layout: FlowListLayout {
topPadding: 6
rightPadding: 6
bottomPadding: 6
leftPadding: 6
}
// A simple data model is loaded with just a header.
// This will be replaced when we load the real one
// from C++.
dataModel: XmlDataModel {
source: "model.xml"
}
listItemComponents: [
// The header list item displays a title along with a counter
// that displays the number of children
ListItemComponent {
type: "header"
HeaderListItem {
topMargin: 8
title: ListItemData.title
subtitle: (ListItem.initialized ?
ListItem.view.dataModel
.childCount(ListItem.indexPath) : 0);
}
},
// The contact list item displays the name of the contact
ListItemComponent {
type: "contacts"
StandardListItem {
title: ListItemData.title
}
}
]
}
// The activity indicator has an object name set so that
// we can start and stop it from C++
ActivityIndicator {
objectName: "indicator"
layoutProperties: DockLayoutProperties {
verticalAlignment: VerticalAlignment.Fill
horizontalAlignment: HorizontalAlignment.Fill
}
}
} // Ends the root Container
} // Ends the Page
} // Ends the TabbedPane
这是我的 QML 文件：
import bb.cascades 1.0
TabbedPane {
activePane: Page {
actions: [
// An action item that calls the C++ function that retrieves
// the contact list
ActionItem {
title: "Refresh"
onTriggered: app.initiateRequest(txtGen.text)
}
]
content: Container {
layout: StackLayout {}
Button {
text: "Get Games"
onClicked: app.initiateRequest(txtGen.text)
}
Label {
text: "Enter Generation (1-5)"
}
TextField {
id: txtGen
}
// A list that has two list item components, one for a header
// and one for contact names. The list has an object name so
// that we can set the data model from C++.
ListView {
objectName: "list"
layout: FlowListLayout {
topPadding: 6
rightPadding: 6
bottomPadding: 6
leftPadding: 6
}
// A simple data model is loaded with just a header.
// This will be replaced when we load the real one
// from C++.
dataModel: XmlDataModel {
source: "model.xml"
}
listItemComponents: [
// The header list item displays a title along with a counter
// that displays the number of children
ListItemComponent {
type: "games"
HeaderListItem {
topMargin: 8
title: ListItemData.generation
subtitle: (ListItem.initialized ?
ListItem.view.dataModel
.childCount(ListItem.indexPath) : 0);
}
},
// The contact list item displays the name of the contact
ListItemComponent {
type: "game"
StandardListItem {
title: ListItemData.title
}
}
]
}
// The activity indicator has an object name set so that
// we can start and stop it from C++
ActivityIndicator {
objectName: "indicator"
layoutProperties: DockLayoutProperties {
verticalAlignment: VerticalAlignment.Fill
horizontalAlignment: HorizontalAlignment.Fill
}
}
} // Ends the root Container
} // Ends the Page
} // Ends the TabbedPane
我的项目目录的 assets/model.xml 下还有一个 xml 文件夹，其中包含以下内容：
<?xml version="1.0" encoding="utf-8"?>
<xml>
<games>
</games>
</xml>
另外，这是我编写的 App.cpp 代码：
#include "app.hpp"
#include <bb/cascades/Application>
#include <bb/cascades/QmlDocument>
#include <bb/cascades/AbstractPane>
#include <bb/cascades/Button>
#include <bb/cascades/TextField>
#include <QDir>
using namespace bb::cascades;
App::App()
{
// Load the QML document and retrieve the root node
QmlDocument *qml = QmlDocument::create("main.qml");
mRoot = qml->createRootNode<AbstractPane>();
// Retrieve the activity indicator from QML so that we can start
// and stop it from C++
mActivityIndicator = mRoot->findChild<ActivityIndicator*>("indicator");
// Retrieve the list so we can set the data model on it once
// we retrieve it
mListView = mRoot->findChild<ListView*>("list");
//mTextField = mRoot->findChild<TextField*>("textField");
//qDebug() << "Generation: " << mTextField->text();
// Expose this class to QML so that we can call its functions from there
qml->setContextProperty("app", this);
// Create a network access manager and connect a custom slot to its
// finished signal
mNetworkAccessManager = new QNetworkAccessManager(this);
Q_ASSERT(connect(mNetworkAccessManager, SIGNAL(finished(QNetworkReply*)), this, SLOT(requestFinished(QNetworkReply*))));
// Displays a warning message if there's an issue connecting the signal
// and slot. This is a good practice with signals and slots as it can
// be easier to mistype a slot or signal definition
//Q_ASSERT(result);
//Q_UNUSED(result);
// Create a file in the application's data directory
mFile = new QFile("data/model.xml");
// Set the scene using the root node
Application::setScene(mRoot);
}
void App::initiateRequest(QString text)
{
// Start the activity indicator
mActivityIndicator->start();
// Create and send the network request
QNetworkRequest request = QNetworkRequest();
request.setUrl(QUrl("http://192.168.1.109/TESTWEBSERVICE/MAKEXML.php")); //https://developer.blackberry.com/cascades/files/documentation/device_platform/networking/model.xml"));
request.setHeader(QNetworkRequest::ContentTypeHeader, "application/x-www-form-urlencoded");
QByteArray bytes;
QUrl params;
params.addQueryItem(QString::fromStdString("generation"), text);
bytes = params.encodedQuery();
mNetworkAccessManager->post(request, bytes);
}
void App::requestFinished(QNetworkReply* reply)
{
// Check the network reply for errors
if (reply->error() == QNetworkReply::NoError) {
// Open the file and print an error if the file cannot be opened
if (!mFile->open(QIODevice::ReadWrite))
{
qDebug() << "\n Failed to open file";
return;
}
mFile->resize(0);
// Write to the file using the reply data and close the file
QByteArray xml = reply->readAll();
mFile->write(xml);
qDebug() << xml;
mFile->flush();
mFile->close();
// Create the data model using the contents of the file. The
// location of the file is relative to the assets directory.
XmlDataModel *dataModel = new XmlDataModel();
dataModel->setSource(QUrl("../../../data/model.xml"));
// Set the new data model on the list and stop the activity indicator
mListView->setDataModel(dataModel);
mActivityIndicator->stop();
}
else
{
qDebug() << "\n Problem with the network";
qDebug() << "\n" << reply->errorString();
}
}
这是我的 App.h 文件：
#ifndef APP_H
#define APP_H
#include <QObject>
#include <QFile>
#include <bb/cascades/ActivityIndicator>
#include <bb/cascades/ListView>
#include <bb/cascades/XMLDataModel>
#include <bb/cascades/AbstractPane>
#include <bb/cascades/TextField>
using namespace bb::cascades;
/*!
* @brief Application GUI object
*/
class App : public QObject
{
Q_OBJECT
public:
/*!
* Constructor.
*/
App();
/*!
* Initiates the network request.
*/
Q_INVOKABLE void initiateRequest(QString text);
private slots:
/*!
* Handles the network reply.
*/
void requestFinished(QNetworkReply* reply);
private:
AbstractPane *mRoot;
ActivityIndicator *mActivityIndicator;
ListView *mListView;
TextField *mTextField;
QNetworkAccessManager *mNetworkAccessManager;
QFile *mFile;
QString apiKey;
QString apiString;
};
#endif // ifndef APP_H
QDebug() 流打印出生成参数为 1 的以下内容：
"<?xml version="1.0" encoding="utf-8"?>
<xml>
<games generation="1">
<game title="green">green</game>
<game title="red">red</game>
<game title="blue">blue</game>
<game title="yellow">yellow</game>
</games>
</xml>"
对于生成参数为 2：
"<?xml version="1.0" encoding="utf-8"?>
<xml>
<games generation="2">
<game title="gold">gold</game>
<game title="silver">silver</game>
<game title="crystal">crystal</game>
</games>
</xml>"
对于生成参数为 3：
"<?xml version="1.0" encoding="utf-8"?>
<xml>
<games generation="3">
<game title="ruby">ruby</game>
<game title="sapphire">sapphire</game>
<game title="emerald">emerald</game>
</games>
</xml>"
对于 Generation 参数为 4：
"<?xml version="1.0" encoding="utf-8"?>
<xml>
<games generation="4">
<game title="perl">perl</game>
<game title="diamond">diamond</game>
<game title="platinum">platinum</game>
</games>
</xml>"
对于 Generation 参数为 5：
"<?xml version="1.0" encoding="utf-8"?>
<xml>
<games generation="5">
<game title="black">black</game>
<game title="white">white</game>
<game title="black 2">black 2</game>
<game title="white 2">white 2</game>
</games>
</xml>"
对于其他任何事情，参数生成是 foo （foo 是占位符）：
"<?xml version="1.0" encoding="utf-8"?>
<xml>
<games generation="foo">
</games>
</xml>"
我不太确定，为什么这不起作用。我尝试四处寻找其他示例，看看是否可以使用它来弄清楚如何使我的代码正常工作，但这没有成功。
我知道这个问题很长，但我想提供尽可能多的关于我在做什么的细节，以获得最佳答案。话虽如此，我真的不认为我的 main.cpp 文件是相关的，所以我不会把它放在这里，除非有人要求查看它。
（我在我的 xml 代码中将 title 属性添加到我的游戏标签中，并在这些标签中放入与主要数据值相同的值，例如转动
<game>yellow</game>
进入
<game title="yellow">yellow</game>
在试图让它在没有 title 属性的情况下使用前者之后，因为我认为这可能会解决我的问题，即使它有点 hackish，但它没有。理想情况下，我想弄清楚如何让它以两种方式工作，在游戏标签中使用和不使用 title 属性。