I want to get file from server

Armin

Hi
I want to get file from server ( download )
I write this code and get error:

void MainWindow::on_pushButton_clicked()
{
QNetworkAccessManager downloadmanager;
QNetworkRequest dl2;
downloadmanager.get(dl2.setUrl(ui->textEdit->toPlainText.toString()));
}

error: '((MainWindow*)this)->MainWindow::ui->Ui::MainWindow::<anonymous>.Ui_MainWindow::textEdit->QTextEdit::toPlainText' does not have class type
downloadmanager.get(dl2.setUrl(ui->textEdit->toPlainText.toString()));
^

Armin

I change my code but get error again :(

void MainWindow::on_pushButton_clicked()
{
QNetworkAccessManager downloadmanager;
QNetworkRequest dl2;
t = ui->textEdit->toPlainText();
downloadmanager.get(dl2.setUrl(QUrl::url(t)));
}

? Offline

Hi! void QNetworkRequest::setUrl(const QUrl &url) returns void, but QNetworkReply *QNetworkAccessManager::get(const QNetworkRequest &request) takes a const QNetworkRequest &.

Armin

Thanks @Wieland
I get error from this code:

void MainWindow::on_pushButton_clicked()
{
t = ui->textEdit->toPlainText();
QNetworkAccessManager::get(QNetworkRequest::setUrl(QUrl::url()));
}

C:\Users\armin\Documents\DownloadManager\mainwindow.cpp:22: error: cannot call member function 'QString QUrl::url(QUrl::FormattingOptions) const' without object
QNetworkAccessManager::get(QNetworkRequest::setUrl(QUrl::url()));
^

SGaist

Hi,

You are calling a normal function as it was static. You need to have a QUrl object if you want to call the url method on it.

jsulm

@Armin said in I want to get file from server:

QNetworkRequest

As @Wieland already told you setUrl() does not return anything. But QNetworkAccessManager::get() expects a QNetworkRequest.
And as @SGaist said calling QUrl::url() is just wrong as url() is not static (and what do you actually expect it to return?).
Why not just

void MainWindow::on_pushButton_clicked()
{
QNetworkAccessManager *downloadmanager = new QNetworkAccessManager(this);
QNetworkRequest dl2;
t = ui->textEdit->toPlainText();
dl2.setUrl(QUrl::url(t));
downloadmanager.get(dl2);
}

You should allocate QNetworkAccessManager on the heap via new because else it will disappear as soon as on_pushButton_clicked() finishes. Important: downloadmanager.get(dl2) is asynchronous! You should really read the documentation.

Armin

Thanks @SGaist and Thanks @jsulm
@jsulm I put your and replace with my code but i get error:

C:\Users\armin\Documents\DownloadManager\mainwindow.cpp:22: error: no matching function for call to 'QUrl::url(QString&)'
dl2.setUrl(QUrl::url(t));
^

C:\Users\armin\Documents\DownloadManager\mainwindow.cpp:23: error: request for member 'get' in 'downloadmanager', which is of pointer type 'QNetworkAccessManager*' (maybe you meant to use '->' ?)
downloadmanager.get(dl2);
^

jsulm

@Armin Well, QUrl does not have a get() method, you just use the constructor (that's why a said you should read documentation):

dl2.setUrl(QUrl(t));

The second error message actually tells you what is wrong:

downloadmanager->get(dl2);

Armin

Really thanks @jsulm

I don't have any error but i replace this code with your code and i don't get error , My new code isn't wrong?

void MainWindow::on_pushButton_clicked()
{
    QNetworkAccessManager downloadmanager;

QNetworkRequest dl2;
t = ui->textEdit->toPlainText();
dl2.setUrl(QUrl(t));
downloadmanager.get(dl2);
}

jsulm

@Armin Are you aware that downloadmanager will be destroyed as soon as void MainWindow::on_pushButton_clicked() terminates? I already said that you should allocate it on the heap using new. downloadmanager.get(dl2) is assynchronous - that means the result will be available later, after downloadmanager.get(dl2) finishes.
Do it like this:

QNetworkAccessManager *downloadmanager = new QNetworkAccessManager(this);

jsulm

@Armin And how do you want to get the result? Currently you do not connect any slots to the signals. You will need http://doc.qt.io/qt-5/qnetworkaccessmanager.html#finished

SGaist

To add to @jsulm, make your downloadmanager a member of MainWindow and initialise it in your constructor, otherwise you are going to uselessly create new QNetworkAccessManager.