Qt网络编程之HTTP编程练习（20200220）

﹏ヽ暗。殇╰゛Y 2023-07-07 04:56 1阅读 0赞

#-------------------------------------------------
    #
    # Project created by QtCreator 2020-02-20T20:09:24
    #
    #-------------------------------------------------
    
    QT       += core gui network
    
    greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
    
    TARGET = myGui6
    TEMPLATE = app
    
    # The following define makes your compiler emit warnings if you use
    # any feature of Qt which as been marked as deprecated (the exact warnings
    # depend on your compiler). Please consult the documentation of the
    # deprecated API in order to know how to port your code away from it.
    DEFINES += QT_DEPRECATED_WARNINGS
    
    # You can also make your code fail to compile if you use deprecated APIs.
    # In order to do so, uncomment the following line.
    # You can also select to disable deprecated APIs only up to a certain version of Qt.
    #DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0
    
    
    SOURCES += main.cpp\
            widget.cpp
    
    HEADERS  += widget.h

#ifndef WIDGET_H
    #define WIDGET_H
    
    #include <QWidget>
    #include <QtNetwork>
    #include <QLabel>
    #include <QTextBrowser>
    #include <QLayout>
    #include <QTextCodec>
    #include <QDebug>
    
    class Widget : public QWidget
    {
        Q_OBJECT
    
    public:
        Widget(QWidget *parent = 0);
        ~Widget();
    
    private:
        QNetworkAccessManager *manager;
        QTextBrowser *myTextBrowser;
    
    private slots:
        void replyFinished(QNetworkReply *reply);
    
    };
    
    #endif // WIDGET_H

#include "widget.h"
    
    Widget::Widget(QWidget *parent)
        : QWidget(parent)
    {
        resize(600,600);
        myTextBrowser = new QTextBrowser;
        QHBoxLayout *mainHBLayout = new QHBoxLayout;
        mainHBLayout->addWidget(myTextBrowser);
        setLayout(mainHBLayout);
        manager = new QNetworkAccessManager(this);
        connect(manager, SIGNAL(finished(QNetworkReply*)),this,SLOT(replyFinished(QNetworkReply*)));
        manager->get(QNetworkRequest(QUrl("https://www.sina.com.cn")));
    
    }
    
    Widget::~Widget()
    {
    
    }
    
    void Widget::replyFinished(QNetworkReply *reply)
    {
        QTextCodec *codec = QTextCodec::codecForName("utf8");
        QString all = codec->toUnicode(reply->readAll());
        myTextBrowser->setText(all);
        reply->deleteLater();
    
    
    }

这里先创建了一个`QNetworkAccessManager`类的实例，它用来发送网络请求和接收应答。然后关联了管理器的`finished()`信号和我们自定义的槽，每当网络应答结束时都会发射这个信号。最后使用了`get()`函数来发送一个网络请求，网络请求使用`QNetworkRequest`类表示，`get()`函数返回一个`QNetworkReply`对象。除了`get()`函数，管理器还提供了发送HTTP POST请求的`post()`函数。

因为`QNetworkReply`继承自`QIODevice`类，所以可以操作一般的I/O设备一样来操作该类。这里使用了`readAll()`函数来读取所有的应答数据，为了正常显示中文，使用了`QTextCodec`类来转换编码。在完成数据的读取后，需要使用`deleteLater()`来删除`replay`对象。

**问题：** 网页内容较大时，会出现卡死想象，暂时还没有解决