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Use QSaveFile in MainWindow examples

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QSaveFile should preferably be used by editor applications to catch
write errors.

Task-number: QTBUG-60635
Change-Id: Ia609435871b56b45714c3dd3d32bbc85b5cb4dd5
Reviewed-by: Paul Wicking <paul.wicking@qt.io>
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
This commit is contained in:
Friedemann Kleint 2019-06-11 14:20:20 +02:00
parent 0ad5e16268
commit 8c9e41cc78
4 changed files with 63 additions and 38 deletions
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9
examples/widgets/doc/src/application.qdoc
View File

@ -327,9 +327,12 @@
\snippet mainwindows/application/mainwindow.cpp 44
\snippet mainwindows/application/mainwindow.cpp 45
Saving a file is very similar to loading one. Here, the
QFile::Text flag ensures that on Windows, "\\n" is converted into
"\\r\\n" to conform to the Windows convension.
Saving a file is similar to loading one. We use QSaveFile to ensure
all data are safely written and existing files are not damaged
should writing fail.
We use the QFile::Text flag to make sure that on Windows, "\\n"
is converted into "\\r\\n" to conform to the Windows convention.
\snippet mainwindows/application/mainwindow.cpp 46
\snippet mainwindows/application/mainwindow.cpp 47

34
examples/widgets/mainwindows/application/mainwindow.cpp
View File

@ -353,24 +353,28 @@ void MainWindow::loadFile(const QString &fileName)
bool MainWindow::saveFile(const QString &fileName)
//! [44] //! [45]
{
QFile file(fileName);
if (!file.open(QFile::WriteOnly | QFile::Text)) {
QMessageBox::warning(this, tr("Application"),
tr("Cannot write file %1:\n%2.")
.arg(QDir::toNativeSeparators(fileName),
file.errorString()));
QString errorMessage;
QGuiApplication::setOverrideCursor(Qt::WaitCursor);
QSaveFile file(fileName);
if (file.open(QFile::WriteOnly | QFile::Text)) {
QTextStream out(&file);
out << textEdit->toPlainText();
if (!file.commit()) {
errorMessage = tr("Cannot write file %1:\n%2.")
.arg(QDir::toNativeSeparators(fileName), file.errorString());
}
} else {
errorMessage = tr("Cannot open file %1 for writing:\n%2.")
.arg(QDir::toNativeSeparators(fileName), file.errorString());
}
QGuiApplication::restoreOverrideCursor();
if (!errorMessage.isEmpty()) {
QMessageBox::warning(this, tr("Application"), errorMessage);
return false;
}
QTextStream out(&file);
#ifndef QT_NO_CURSOR
QGuiApplication::setOverrideCursor(Qt::WaitCursor);
#endif
out << textEdit->toPlainText();
#ifndef QT_NO_CURSOR
QGuiApplication::restoreOverrideCursor();
#endif
setCurrentFile(fileName);
statusBar()->showMessage(tr("File saved"), 2000);
return true;

29
examples/widgets/mainwindows/mdi/mdichild.cpp
View File

@ -115,19 +115,28 @@ bool MdiChild::saveAs()
bool MdiChild::saveFile(const QString &fileName)
{
QFile file(fileName);
if (!file.open(QFile::WriteOnly | QFile::Text)) {
QMessageBox::warning(this, tr("MDI"),
tr("Cannot write file %1:\n%2.")
.arg(QDir::toNativeSeparators(fileName), file.errorString()));
QString errorMessage;
QGuiApplication::setOverrideCursor(Qt::WaitCursor);
QSaveFile file(fileName);
if (file.open(QFile::WriteOnly | QFile::Text)) {
QTextStream out(&file);
out << toPlainText();
if (!file.commit()) {
errorMessage = tr("Cannot write file %1:\n%2.")
.arg(QDir::toNativeSeparators(fileName), file.errorString());
}
} else {
errorMessage = tr("Cannot open file %1 for writing:\n%2.")
.arg(QDir::toNativeSeparators(fileName), file.errorString());
}
QGuiApplication::restoreOverrideCursor();
if (!errorMessage.isEmpty()) {
QMessageBox::warning(this, tr("MDI"), errorMessage);
return false;
}
QTextStream out(&file);
QGuiApplication::setOverrideCursor(Qt::WaitCursor);
out << toPlainText();
QGuiApplication::restoreOverrideCursor();
setCurrentFile(fileName);
return true;
}

29
examples/widgets/mainwindows/sdi/mainwindow.cpp
View File

@ -425,19 +425,28 @@ void MainWindow::openRecentFile()
bool MainWindow::saveFile(const QString &fileName)
{
QFile file(fileName);
if (!file.open(QFile::WriteOnly | QFile::Text)) {
QMessageBox::warning(this, tr("SDI"),
tr("Cannot write file %1:\n%2.")
.arg(QDir::toNativeSeparators(fileName), file.errorString()));
QString errorMessage;
QGuiApplication::setOverrideCursor(Qt::WaitCursor);
QSaveFile file(fileName);
if (file.open(QFile::WriteOnly | QFile::Text)) {
QTextStream out(&file);
out << textEdit->toPlainText();
if (!file.commit()) {
errorMessage = tr("Cannot write file %1:\n%2.")
.arg(QDir::toNativeSeparators(fileName), file.errorString());
}
} else {
errorMessage = tr("Cannot open file %1 for writing:\n%2.")
.arg(QDir::toNativeSeparators(fileName), file.errorString());
}
QGuiApplication::restoreOverrideCursor();
if (!errorMessage.isEmpty()) {
QMessageBox::warning(this, tr("SDI"), errorMessage);
return false;
}
QTextStream out(&file);
QGuiApplication::setOverrideCursor(Qt::WaitCursor);
out << textEdit->toPlainText();
QGuiApplication::restoreOverrideCursor();
setCurrentFile(fileName);
statusBar()->showMessage(tr("File saved"), 2000);
return true;