Shrink QMainWindow to Minimum Size

[fanat9]

Well, again you have to set correct size/size policy for all widgets. Check sizeHint's for your widgets before and after resizing - it will tell you a lot =)
...override sizeHint ? Try to set maximum, not minimum size =)

[kloffy]

After trying out various combinations I came up with this:

ApplicationWindow::ApplicationWindow(QWidget* parent) : QMainWindow(parent, Qt::WindowTitleHint |  Qt::WindowMinimizeButtonHint | Qt::WindowSystemMenuHint)
{
	setWindowTitle(tr("QTApp"));
	setSizePolicy(QSizePolicy::Minimum, QSizePolicy::Minimum);
	setMinimumSize(400, 150);
 
	createActions();
	createMenus();
 
	center = new QWidget(this);
	center->setSizePolicy(QSizePolicy::Minimum, QSizePolicy::Minimum);
 
	QStringList types;
	types << "Executable Files (*.exe)" << "Any files (*)";
 
	fileDialog = new QFileDialog(this);
	fileDialog->setWindowTitle(tr("Select a program"));
	fileDialog->setAcceptMode(QFileDialog::AcceptOpen);
	fileDialog->setFilters(types);
 
	QGroupBox *groupBoxOptions = new QGroupBox(tr("Options"), center);
	QGridLayout *layoutOptions = new QGridLayout(groupBoxOptions);
 
	exepathEdit = new QLineEdit(groupBoxOptions);
	cmdlineEdit = new QLineEdit(groupBoxOptions);
 
	buttonSelectFile = new QPushButton(tr("Select..."), groupBoxOptions);
 
	connect(buttonSelectFile, SIGNAL(clicked()), this, SLOT(selectFile()));
 
	layoutOptions->addWidget(new QLabel(tr("Exepath:")), 1, 1);
	layoutOptions->addWidget(exepathEdit, 1, 2);
	layoutOptions->addWidget(buttonSelectFile, 1, 3);
 
	layoutOptions->addWidget(new QLabel(tr("Cmdline:")), 2, 1);
	layoutOptions->addWidget(cmdlineEdit, 2, 2, 1, 2);
 
	layoutOptions->setColumnStretch(1, 20);
	layoutOptions->setColumnStretch(2, 60);
	layoutOptions->setColumnStretch(3, 20);
 
	groupBoxOptions->setLayout(layoutOptions);
 
	dock = new QDockWidget(tr("Output"), this);
	dock->setAllowedAreas(Qt::BottomDockWidgetArea);
	dock->setFeatures(QDockWidget::DockWidgetClosable);
 
	textEdit = new QTextEdit(dock);
	textEdit->setReadOnly(true);
	textEdit->setFixedHeight(100);
 
	dock->setWidget(textEdit);
 
	addDockWidget(Qt::BottomDockWidgetArea, dock);
 
	viewMenu->addAction(dock->toggleViewAction());
 
	connect(dock, SIGNAL(visibilityChanged(bool)), this, SLOT(adjust()));
 
	buttonStart = new QPushButton(tr("Start"));
	buttonStart->setDefault(true);
 
	connect(buttonStart, SIGNAL(clicked()), this, SLOT(start()));
 
	QHBoxLayout *buttonLayout = new QHBoxLayout;
	buttonLayout->addStretch(1);
	buttonLayout->addWidget(buttonStart);
	buttonLayout->addStretch(1);
 
	QVBoxLayout *centerLayout = new QVBoxLayout;
	centerLayout->addWidget(groupBoxOptions);
	centerLayout->addLayout(buttonLayout);
	center->setLayout(centerLayout);
 
	setCentralWidget(center);
}
 
void ApplicationWindow::adjust()
{
	adjustSize();
}

ApplicationWindow::ApplicationWindow(QWidget* parent) : QMainWindow(parent, Qt::WindowTitleHint |  Qt::WindowMinimizeButtonHint | Qt::WindowSystemMenuHint)
{
	setWindowTitle(tr("QTApp"));
	setSizePolicy(QSizePolicy::Minimum, QSizePolicy::Minimum);
	setMinimumSize(400, 150);

	createActions();
	createMenus();

	center = new QWidget(this);
	center->setSizePolicy(QSizePolicy::Minimum, QSizePolicy::Minimum);

	QStringList types;
	types << "Executable Files (*.exe)" << "Any files (*)";

	fileDialog = new QFileDialog(this);
	fileDialog->setWindowTitle(tr("Select a program"));
	fileDialog->setAcceptMode(QFileDialog::AcceptOpen);
	fileDialog->setFilters(types);

	QGroupBox *groupBoxOptions = new QGroupBox(tr("Options"), center);
	QGridLayout *layoutOptions = new QGridLayout(groupBoxOptions);

	exepathEdit = new QLineEdit(groupBoxOptions);
	cmdlineEdit = new QLineEdit(groupBoxOptions);

	buttonSelectFile = new QPushButton(tr("Select..."), groupBoxOptions);

	connect(buttonSelectFile, SIGNAL(clicked()), this, SLOT(selectFile()));

	layoutOptions->addWidget(new QLabel(tr("Exepath:")), 1, 1);
	layoutOptions->addWidget(exepathEdit, 1, 2);
	layoutOptions->addWidget(buttonSelectFile, 1, 3);

	layoutOptions->addWidget(new QLabel(tr("Cmdline:")), 2, 1);
	layoutOptions->addWidget(cmdlineEdit, 2, 2, 1, 2);

	layoutOptions->setColumnStretch(1, 20);
	layoutOptions->setColumnStretch(2, 60);
	layoutOptions->setColumnStretch(3, 20);

	groupBoxOptions->setLayout(layoutOptions);

	dock = new QDockWidget(tr("Output"), this);
	dock->setAllowedAreas(Qt::BottomDockWidgetArea);
	dock->setFeatures(QDockWidget::DockWidgetClosable);

	textEdit = new QTextEdit(dock);
	textEdit->setReadOnly(true);
	textEdit->setFixedHeight(100);

	dock->setWidget(textEdit);

	addDockWidget(Qt::BottomDockWidgetArea, dock);

	viewMenu->addAction(dock->toggleViewAction());

	connect(dock, SIGNAL(visibilityChanged(bool)), this, SLOT(adjust()));

	buttonStart = new QPushButton(tr("Start"));
	buttonStart->setDefault(true);

	connect(buttonStart, SIGNAL(clicked()), this, SLOT(start()));

	QHBoxLayout *buttonLayout = new QHBoxLayout;
	buttonLayout->addStretch(1);
	buttonLayout->addWidget(buttonStart);
	buttonLayout->addStretch(1);

	QVBoxLayout *centerLayout = new QVBoxLayout;
	centerLayout->addWidget(groupBoxOptions);
	centerLayout->addLayout(buttonLayout);
	center->setLayout(centerLayout);

	setCentralWidget(center);
}

void ApplicationWindow::adjust()
{
	adjustSize();
}

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There is something about having a minimumSize on the QMainWindow and a fixedHeight on the dock widget that makes it work. It's not a nice solution - I had to sacrifice floating and the dock widget cannot be resized - but it'll do for now. I would still love to find a propper way of doing this. Here's a quick and dirty ASCII art:

Without Dock:
 ____________________
|Main                |
|--------------------|
| .-Options---------.|
| | Exe: [Blablub ] ||
| | Cmd: [Blablub ] ||
| |_________________||
|       [Start]      |
|____________________|
 
With dock:
 ____________________
|Main                |
|--------------------|
| .-Options---------.|
| | Exe: [Blablub ] ||
| | Cmd: [Blablub ] ||
| |_________________||
|       [Start]      |
|--------------------|
|Output             x|
| .-----------------.|
| |Blablub...       ||
| |Blablub...       ||
| |                 ||
| |_________________||
|____________________|

Without Dock:
 ____________________
|Main                |
|--------------------|
| .-Options---------.|
| | Exe: [Blablub ] ||
| | Cmd: [Blablub ] ||
| |_________________||
|       [Start]      |
|____________________|

With dock:
 ____________________
|Main                |
|--------------------|
| .-Options---------.|
| | Exe: [Blablub ] ||
| | Cmd: [Blablub ] ||
| |_________________||
|       [Start]      |
|--------------------|
|Output             x|
| .-----------------.|
| |Blablub...       ||
| |Blablub...       ||
| |                 ||
| |_________________||
|____________________|

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It doesn't have to be a dock, if anyone knows a custom widget that allows you to do something like this, I would appreciate if you point me to it.