QT 子线程 更改UI

一、问题原因：

QT和Android类似，不能在子线程中直接更新UI，否则会有崩溃；

二、实现方式

方式有几种，我这里只说一种，使用 信号机制；

三、原理：

原理其实是信号槽机制，槽连接方式：

有以下四种，如果未设置默认 auto,即可跨线程通信;

Direction、queued、blockingqueued、unique、auto

四、实现步骤：

首先 MainWindow 声明，定义（UI 线程）

public  slots:
   // 参数类型，注册最好不要自定义
   void sltCallBackkSocketState(int state,QString socketInfo );

void MainWindow::sltCallBackkSocketState(int state,QString socketInfo )
{
     //通过信号槽过来，可以直接修改UI
     ui->label_connect_state->setText(socketInfo);
}

  MainWindow  中，通过connect 将 信号和槽连结起来

mWorker = new HMyTcpWorker(mSocketCallInterface,m_nHandle);
    m_thread = new QThread(mWorker);
    mWorker->moveToThread(m_thread);

    connect(mWorker, SIGNAL(sigCallBackkSocketState(int,QString)),
          this, SLOT(sltCallBackkSocketState(int,QString)));

子线程

signals:
  

    void sigCallBackkSocketState(int state,QString socketInfo );

void HMyTcpWorker::onError(QAbstractSocket::SocketError)
{
    QTcpSocket* sock = (QTcpSocket*)sender();

    if(QAbstractSocket::ConnectedState != sock->state())
    {
      emit sigCallBackkSocketState(SOCKET_STATE_ERROR,sock->errorString());
    }
    qDebug() << "Socket error:" << sock->errorString();
}

以下是全部代码：

MainWindow  

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include "HMyTcpClient.h"
#include <QtNetwork>
#include <QTcpSocket>
#include <QHostAddress>

#include <QDataStream>
#include <QByteArray>
#include <QDebug>
#include <QDateTime>
#include <QFile>
#include "HMyTcpWorker.h"

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();

 

private:
    Ui::MainWindow *ui;


public  slots:
   // 参数类型，注册最好不要自定义
   void sltCallBackkSocketState(int state,QString socketInfo );

 

private:
HMyTcpWorker * mWorker;
  
};

#endif // MAINWINDOW_H

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QGridLayout>
#include <QDebug>
 
#include <qfiledialog.h>
#include <qfile.h>
#include <qstring.h>

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
 
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
 

    this->setWindowTitle("Client");
    ui->mainToolBar->setVisible (false);// 
    ui->label_connect_state->setText("未连接");

   mWorker = new HMyTcpWorker(mSocketCallInterface,m_nHandle);
    m_thread = new QThread(mWorker);
    mWorker->moveToThread(m_thread);

    connect(mWorker, SIGNAL(sigCallBackkSocketState(int,QString)),
          this, SLOT(sltCallBackkSocketState(int,QString)));

 
}

MainWindow::~MainWindow()
{
    delete ui;
}

 void MainWindow::sltCallBackkSocketState(int state,QString socketInfo )
{
     ui->label_connect_state->setText(socketInfo);
}

HMyTcpWorker

#ifndef HMYTCPWORKER_H
#define HMYTCPWORKER_H

#include <QObject>
#include "HMyTcpSocket.h"
#include <QTcpSocket>
#include <QDateTime>
#include <QFile>
#include "socketcallinterface.h"

class HMyTcpWorker : public QObject
{
    Q_OBJECT
public:
    explicit HMyTcpWorker(qintptr socketHandle, QObject *parent = 0);
    ~HMyTcpWorker();
 

 
private:
    HMyTcpSocket* m_tcpSocket;
 


signals:
  

    void sigCallBackkSocketState(int state,QString socketInfo );

public slots:
    
     void  onConnect();


     void  onError(QAbstractSocket::SocketError);

private:
  

        系统时间
        QDateTime current_date_time;
        QString str_date_time;
};

#endif // HMYTCPWORKER_H

#include "HMyTcpWorker.h"
#include <QDebug>
#include <QXmlStreamReader>
#include <QDataStream>

#include <QMessageBox>

HMyTcpWorker::HMyTcpWorker( qintptr socketHandle, QObject *parent)
    : QObject(parent),
      m_nID(socketHandle),
      mSocketCallInterface(interface)
{
    m_tcpSocket = NULL;
 
}

HMyTcpWorker::~HMyTcpWorker()
{
    qDebug() << QString::fromLocal8Bit("析构……。……。……。……。……。……………。");
}

 
 
void HMyTcpWorker::sltConnectServer(QString hostName, int port, int timeout)
{
    if(NULL == m_tcpSocket)
    {
        m_tcpSocket = new HMyTcpSocket(m_nID);
 
         connect(m_tcpSocket, SIGNAL(error(QAbstractSocket::SocketError)),
                 this, SLOT(onError(QAbstractSocket::SocketError)));
          connect(m_tcpSocket, SIGNAL(connected()), this, SLOT(onConnect()));

      
    }

    if(m_tcpSocket)
    {
        m_tcpSocket->connectToHost(hostName, port);
        if(!m_tcpSocket->waitForConnected(timeout))
        {
            qDebug()<<"conncet to server is timeout";
            emit sigResult(-1);
        }
        else
        {
            emit sigResult(0);
        }
    }
}

 
void HMyTcpWorker::onConnect()
{
    qDebug() << "Connected!";
}

void HMyTcpWorker::onError(QAbstractSocket::SocketError)
{
    QTcpSocket* sock = (QTcpSocket*)sender();

    if(QAbstractSocket::ConnectedState != sock->state())
    {
      emit sigCallBackkSocketState(SOCKET_STATE_ERROR,sock->errorString());
    }
    qDebug() << "Socket error:" << sock->errorString();
}