我必须执行很多获取请求,并且必须以不同的方式处理它们。到目前为止,我有这种简单有效的方法:
下面是.h
的代码:
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include <QNetworkAccessManager>
#include <QNetworkRequest>
#include <QNetworkReply>
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = nullptr);
~MainWindow();
private slots:
void on_pushButton_clicked();
void on_pushButton_2_clicked();
void finish(QNetworkReply *reply);
void finish2(QNetworkReply *reply);
private:
Ui::MainWindow *ui;
QNetworkAccessManager* manager;
};
#endif // MAINWINDOW_H
.cpp
的代码:
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QDebug>
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
}
MainWindow::~MainWindow()
{
delete ui;
}
//First request here...
void MainWindow::on_pushButton_clicked()
{
manager = new QNetworkAccessManager(this);
connect(manager, &QNetworkAccessManager::finished, this, &MainWindow::finish);
manager->get(QNetworkRequest{QUrl{"http://www.link.com/path/"}});
}
//... is completed here
void MainWindow::finish(QNetworkReply *reply) {
if (reply->error()) {
ui->lineEdit->setText("error");
qDebug() << reply->errorString();
} else {
ui->lineEdit->setText(QString{reply->readAll()});
}
}
//Second request here...
void MainWindow::on_pushButton_2_clicked()
{
manager = new QNetworkAccessManager(this);
connect(manager, &QNetworkAccessManager::finished, this, &MainWindow::finish2);
manager->get(QNetworkRequest{QUrl{"https://ergast.com/api/f1/2008/5.json"}});
qDebug() << "chiamata";
}
//... is completed here
void MainWindow::finish2(QNetworkReply *reply) {
if (reply->error()) {
ui->lineEdit_2->setText("error");
qDebug() << reply->errorString();
} else {
ui->lineEdit_2->setText(QString{reply->readAll()});
}
}
当我按下两个按钮时,请求发生但我的 UI 阻塞。我已经尝试过这种方法,因为我在许多示例中看到将 QNetworkAccessManager* manager;
作为私有(private)字段并重新使用它是很好的。
顺便说一句,这似乎不是最好的方法。有没有正确的方法来进行多次调用?
我是否应该声明一个 QNetworkAccessManager*
数组并在那里执行所有调用?
我还看到可以创建一个名为 QNetworkReply* reply;
的私有(private)字段,然后像这样使用它:
manager = new QNetworkAccessManager(this);
reply = manager->get(QNetworkRequest{QUrl{"http://www.link.com/path/"}});
connect(manager, &QNetworkReply::finished, this, &MainWindow::finish);
我认为这等同于我正在使用的方法,但在这种情况下我不知道如何处理多个请求,因为我绑定(bind)到 finish
方法并且我应该实现所有那里的逻辑。
最佳答案
我已经测试了你的代码,但我没有注意到 GUI 被阻塞,除了使用信号和槽之外你不应该有那个问题。但是我看到您不必要地创建动态内存,在下面的代码中,我将 QNetworkReply
连接到一个插槽,过滤 QUrl
并删除 QNetworkReply
:
*.h
...
private slots:
void on_pushButton_clicked();
void on_pushButton_2_clicked();
void onReplyfinished();
private:
Ui::MainWindow *ui;
QNetworkAccessManager *manager;
...
*.cpp
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
manager = new QNetworkAccessManager(this);
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::on_pushButton_clicked()
{
QNetworkReply *reply = manager->get(QNetworkRequest{QUrl{"http://www.link.com/path/"}});
connect(reply, &QNetworkReply::finished, this, &MainWindow::onReplyfinished);
}
void MainWindow::on_pushButton_2_clicked()
{
QNetworkReply *reply = manager->get(QNetworkRequest{QUrl{"https://ergast.com/api/f1/2008/5.json"}});
connect(reply, &QNetworkReply::finished, this, &MainWindow::onReplyfinished);
}
void MainWindow::onReplyfinished()
{
QNetworkReply *reply = qobject_cast<QNetworkReply*>(sender());
if(reply->url() == QUrl{"http://www.link.com/path/"}){
ui->lineEdit->setText(reply->error() ? "error": reply->readAll());
}
else if (reply->url() == QUrl{"https://ergast.com/api/f1/2008/5.json"}){
ui->lineEdit_2->setText(reply->error() ? "error": reply->readAll());
}
reply->deleteLater();
}
关于c++ - Qt 使用 QNetworkAccessManager 执行多个 get,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/53111453/