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。