Between two dockwidgets, how to change the size of one dock when the other is changed?

kaien

I have two dockwidgets (one Top and one bottom). In both of them, there are some other widgets. I hope that when the size of one dock is changed, the other one (as well as the Inside widgets) will be changed accordingly.
My question is that, once I incrise the size of the buttom dock, and decrise it again, the top dock will not be changed accordingly. Please see the picture as follows:

Does anyone can help to make it work?
Please find the .ui file as well here: [0_1506843876276_QtGuiApplication2.ui](Uploading 100%)
Thanks in advance!

mrjj

Hi
Did you use layout for the inside widgets?
That will normally take care of scaling to the size of the dock so they take up all space.

kaien

Sorry, as a new user, I am not allowed to upload .ui file. but i hope that it will be not difficult to see the problem. Looking forwards to any suggestion and remark. Thanks a lot!

mrjj

@kaien
Im not sure any of us can upload Ui files. :)

They are text, so you can just paste it as text here.

And welcome to the forums.

mrjj

Anyway
if your issue is that widgets you place inside the dock do not follow
the dock size, you should have a look at layouts
http://doc.qt.io/qt-5/layout.html
They are for that.

kaien

@mrjj Thanks for your reply and suggestions. Here is the ui file:

<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
 <class>QtGuiApplication2Class</class>
 <widget class="QMainWindow" name="QtGuiApplication2Class">
  <property name="geometry">
   <rect>
    <x>0</x>
    <y>0</y>
    <width>664</width>
    <height>485</height>
   </rect>
  </property>
  <property name="windowTitle">
   <string>QtGuiApplication2</string>
  </property>
  <widget class="QWidget" name="centralWidget"/>
  <widget class="QMenuBar" name="menuBar">
   <property name="geometry">
    <rect>
     <x>0</x>
     <y>0</y>
     <width>664</width>
     <height>23</height>
    </rect>
   </property>
  </widget>
  <widget class="QDockWidget" name="dockWidget_3">
   <attribute name="dockWidgetArea">
    <number>4</number>
   </attribute>
   <widget class="QWidget" name="dockWidgetContents_3">
    <layout class="QVBoxLayout" name="verticalLayout_2">
     <item>
      <widget class="QMdiArea" name="mdiArea_2"/>
     </item>
    </layout>
   </widget>
  </widget>
  <widget class="QDockWidget" name="dockWidget_4">
   <attribute name="dockWidgetArea">
    <number>8</number>
   </attribute>
   <widget class="QWidget" name="dockWidgetContents_4">
    <layout class="QVBoxLayout" name="verticalLayout">
     <item>
      <widget class="QListWidget" name="listWidget"/>
     </item>
    </layout>
   </widget>
  </widget>
 </widget>
 <layoutdefault spacing="6" margin="11"/>
 <resources>
  <include location="QtGuiApplication2.qrc"/>
 </resources>
 <connections/>
</ui>

Thanks a lot for your help.

mrjj

Hi
It seems you did use layout ?
If you float the dock and drag the border , does the inside widgets rescale ?

kaien

@mrjj said in Between two dockwidgets, how to change the size of one dock when the other is changed?:

Hi
It seems you did use layout ?
If you float the dock and drag the border , does the inside widgets rescale ?

The Inside widgets of top dock rescale when the bottom one up, but not change when the bottom one down.

mrjj

@kaien
that sounds odd , they should always rescale no matter if up or down.

If you play around with this
http://doc.qt.io/qt-5/qtwidgets-mainwindows-mainwindow-example.html
you will see that there is never space between the docks
so i think its inside widgets that something up.

So my best guess is that your layout inside dock widget is not working since it dont
take all space.

Show the code that creates the docks.

kaien

@mrjj I've tried some ways to use layout.

The first think is to set a QVBoxLayout as a centralWidget, then I can put two docks Inside.
Here is the code

#include "stdafx.h"
#include "QtGuiApplication2.h"

QtGuiApplication2::QtGuiApplication2(QWidget *parent)
	: QMainWindow(parent)
{
	ui.setupUi(this);
	QVBoxLayout *mainlayout = new QVBoxLayout(this);
	mainlayout->addWidget(ui.dockWidget);
	mainlayout->addWidget(ui.dockWidget_4);
	ui.centralWidget->setLayout(mainlayout);
}

However, this is not what I want since I found that I can not drag the border of docks anymore, and once it float, it can not be docked again.

The second try is to add top dock Inside of centralWidget as follows:

#include "stdafx.h"
#include "QtGuiApplication2.h"

QtGuiApplication2::QtGuiApplication2(QWidget *parent)
	: QMainWindow(parent)
{
	ui.setupUi(this);
	QVBoxLayout *mainlayout = new QVBoxLayout(this);
	mainlayout->addWidget(ui.dockWidget);
	ui.centralWidget->setLayout(mainlayout);
}

This time, I really get what I want without that gap, but I can not dock anymore the top dockWidget!

If I don't define centralWidget and just use defaut setting as:

Then I can dock the two dockwidgets, but I will get the problem asked in this post.

So could you please give me an example to show how to do it in a correct way.
Thanks a lot!

kaien

@mrjj Here is all codes for this sample:

main.cpp

#include "mainwindow.h"
#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    w.show();

    return a.exec();
}

mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
}

MainWindow::~MainWindow()
{
    delete ui;
}

mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();

private:
    Ui::MainWindow *ui;
};

#endif // MAINWINDOW_H

mainwindow.ui

<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
 <class>MainWindow</class>
 <widget class="QMainWindow" name="MainWindow">
  <property name="geometry">
   <rect>
    <x>0</x>
    <y>0</y>
    <width>746</width>
    <height>500</height>
   </rect>
  </property>
  <property name="windowTitle">
   <string>MainWindow</string>
  </property>
  <widget class="QWidget" name="centralWidget"/>
  <widget class="QMenuBar" name="menuBar">
   <property name="geometry">
    <rect>
     <x>0</x>
     <y>0</y>
     <width>746</width>
     <height>23</height>
    </rect>
   </property>
  </widget>
  <widget class="QToolBar" name="mainToolBar">
   <attribute name="toolBarArea">
    <enum>TopToolBarArea</enum>
   </attribute>
   <attribute name="toolBarBreak">
    <bool>false</bool>
   </attribute>
  </widget>
  <widget class="QStatusBar" name="statusBar"/>
  <widget class="QDockWidget" name="dockWidget">
   <attribute name="dockWidgetArea">
    <number>4</number>
   </attribute>
   <widget class="QWidget" name="dockWidgetContents">
    <layout class="QVBoxLayout" name="verticalLayout_2">
     <item>
      <widget class="QMdiArea" name="mdiArea"/>
     </item>
    </layout>
   </widget>
  </widget>
  <widget class="QDockWidget" name="dockWidget_2">
   <attribute name="dockWidgetArea">
    <number>8</number>
   </attribute>
   <widget class="QWidget" name="dockWidgetContents_2">
    <layout class="QVBoxLayout" name="verticalLayout">
     <item>
      <widget class="QListWidget" name="listWidget"/>
     </item>
    </layout>
   </widget>
  </widget>
 </widget>
 <layoutdefault spacing="6" margin="11"/>
 <resources/>
 <connections/>
</ui>

kaien

Ok, very a lot of tests, finally, I found a way to solve the problem.
We just need to add central Widget as of one of the dock widget, for example, the top widget as

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    setCentralWidget(ui.dockWidget);
}

Then everything will be all right! I got excatly what I want :)
Thanks @mrjj for your discussion.

mrjj

@kaien
Super
Normally the docks only likes do dock to the sides of central but it seems you
found a way :)