QML 从无到有 3 （自动更新）

新的需求出来啦，需要自动更新功能，不怕程序升级了。

自动更新，QML不好写，需要c++来辅助，这里就涉及QML中调用c++功能（这里就不写了，百度一下，很多）。

思路：获取版本》下载程序》安装程序

第一步，获取版本信息，可以通过XMLHttpRequest获取最新版本。

第二步，下载程序，通过Qt c++的QtNetwork：

头文件：

 #ifndef ZRDOWNLOAD_H

 #define ZRDOWNLOAD_H

 #include <QObject>

 #include <QtNetwork/QNetworkAccessManager>

 #include <QFile>

 #include <QtNetwork/QNetworkReply>

 #include <QtNetwork/QNetworkRequest>

 #include <QIODevice>

 class ZRDownload : public QObject

 {

     Q_OBJECT

     Q_PROPERTY(QString url READ GetUrl WRITE SetUrl)

     Q_PROPERTY(QString fileName READ GetFileName WRITE SetFileName)

 public:

     explicit ZRDownload(QObject *parent = );

     ~ZRDownload();

     QString GetUrl();

     void SetUrl(QString u);

     QString GetFileName();

     void SetFileName(QString fn);

 private:

     QString url;

     QString fileName;

     QFile *file;

     QNetworkAccessManager *accessManager;

     QNetworkRequest request;

     QNetworkReply *reply;

 signals:

     void progressPosition(double pre);  //更新进度条信号

     void downloadFinished();            //结束信号

 protected slots:

     void httpDownload();

     void replyFinished(QNetworkReply*reply);

     void onDownloadProgress(qint64 bytesSent,qint64 bytesTotal);

     void onReadyRead();

 };

 #endif // ZRDOWNLOAD_H

CPP文件：

#include "zrdownload.h"

#include <QDebug>

ZRDownload::ZRDownload(QObject *parent) : QObject(parent)

{

    accessManager = NULL;

    reply = NULL;

}

ZRDownload::~ZRDownload()

{

}

QString ZRDownload::GetUrl()

{

    return url;

}

void ZRDownload::SetUrl(QString u)

{

    url = u;

}

QString ZRDownload::GetFileName()

{

    return fileName;

}

void ZRDownload::SetFileName(QString fn)

{

    fileName = fn;

}

void ZRDownload::httpDownload(){

  file=new QFile(fileName);

  bool suc = file->open(QIODevice::WriteOnly);//只读方式打开文件

  accessManager=new QNetworkAccessManager(this);

  request.setUrl(url);

  /******************设置http的header***********************/

  // request.setHeader(QNetworkRequest::ContentTypeHeader, "multipart/form-data");

  // request.setHeader(QNetworkRequest::ContentTypeHeader, "application/octet-stream");

  // request.setRawHeader("Content-Disposition","form-data;name='doc';filename='a.txt'");

  //request.setHeader(QNetworkRequest::ContentLengthHeader,post_data.length());

  reply=accessManager->get(request);//通过发送数据，返回值保存在reply指针里.

  connect(accessManager, SIGNAL(finished(QNetworkReply*)), this, SLOT(replyFinished(QNetworkReply*)));//finish为manager自带的信号，replyFinished是自定义的

  connect(reply, SIGNAL(downloadProgress(qint64,qint64)), this, SLOT( onDownloadProgress(qint64 ,qint64 )));//download文件时进度

  connect((QObject *)reply, SIGNAL(readyRead()),this, SLOT(onReadyRead()));

}

/***************响应结束**************************/

void ZRDownload::replyFinished(QNetworkReply *reply){

  //获取响应的信息，状态码为200表示正常

  QVariant status_code = reply->attribute(QNetworkRequest::HttpStatusCodeAttribute);

  QByteArray bytes = reply->readAll();  //获取字节

  QString result(bytes);  //转化为字符串

  //无错误返回

  if(reply->error() == QNetworkReply::NoError)

  {

    QByteArray bytes = reply->readAll();  //获取字节

    QString result(bytes);  //转化为字符串

    file->flush();

    file->close();

    delete file;

    file=NULL;

  }

  else

  {

    //处理错误

  }

  reply->deleteLater();//要删除reply，但是不能在repyfinished里直接delete，要调用deletelater;

  reply=NULL;

  accessManager->deleteLater();

  accessManager=NULL;

  downloadFinished();

}

/***********更新进度条*************/

void ZRDownload::onDownloadProgress(qint64 bytesSent, qint64 bytesTotal){

    double pre = double(bytesSent)/bytesTotal;

    progressPosition(pre);

}

void ZRDownload::onReadyRead(){

  file->write(reply->readAll());

}

上面的代码也是修改网上的代码，增加了QML调用的信息。

注意：项目文件pro中需要添加 QT += network

main.cpp：

添加 qmlRegisterType<ZRDownload>("xxx.xxx.ZRDownload", 1, 0, "ZRDownload");

QML调用：

 ZRDownload{

         id:download

         url:"http://xxx.xxx.com/xx.apk"

         fileName:""

         onProgressPosition:progressBar.update(pre) //自定义更新进度条函数

         onDownloadFinished: {

             //下载完成

         }

     }

 //启动下载

 download.fileName=getAppPath();//设置保存目录，pc和安卓不同

 download.httpDownload();

第三步，安装程序：

不同平台，安装程序的代码也不同，PC平台使用QProcess启动安装程序，安卓平台通过QAndroidJniObject调用Activity实现。下面是代码：

 #ifndef ZRINSTALL_H

 #define ZRINSTALL_H

 #include <QObject>

 #include <QString>

 class ZRInstall : public QObject

 {

     Q_OBJECT

     Q_PROPERTY(QString fileName WRITE SetFileName)

 public:

     explicit ZRInstall(QObject *parent = );

     void SetFileName(QString fn);

 signals:

 public slots:

     void install();

 private:

     QString m_FileName;

 };

 #endif // ZRINSTALL_H

头文件

 #include "zrinstall.h"

 #include <QDebug>

 #if defined(Q_OS_ANDROID)

 #include <QtAndroid>

 #else

 #include <QProcess>

 #endif

 ZRInstall::ZRInstall(QObject *parent) : QObject(parent)

 {

 }

 void ZRInstall::SetFileName(QString fn)

 {

     m_FileName = fn;

 }

 void ZRInstall::install()

 {

 #if defined(Q_OS_ANDROID)

     //安装apk

     QAndroidJniObject path = QAndroidJniObject::fromString("file://"+m_FileName);

     QAndroidJniObject uri = QAndroidJniObject::callStaticObjectMethod("android/net/Uri", "parse", "(Ljava/lang/String;)Landroid/net/Uri;", path.object<jstring>());

     QAndroidJniObject param = QAndroidJniObject::getStaticObjectField<jstring>("android/content/Intent", "ACTION_VIEW");

     QAndroidJniObject intent("android/content/Intent","(Ljava/lang/String;)V",param.object<jstring>());

     QAndroidJniObject type = QAndroidJniObject::fromString("application/vnd.android.package-archive");

     QAndroidJniObject result = intent.callObjectMethod("setDataAndTypeAndNormalize", "(Landroid/net/Uri;Ljava/lang/String;)Landroid/content/Intent;", uri.object<jobject>(), type.object<jstring>());

     QtAndroid::startActivity(intent, , );

 #else

     //qDebug()<<m_FileName;

     QProcess * proc = new QProcess();

     proc->startDetached(m_FileName,QStringList());

     delete proc;

 #endif

 }

CPP文件

 android{

     QT += androidextras

 }

项目文件pro

调用就不写了，可以参考上面download。

这样整个版本自动更新就写好了，有一些细节自己需要注意，如下载安装文件不同，安装目录不同。