Prerequisites

All operations in this guide are based on Ubuntu 18.04 LTS 64bit only.
First please install Ubuntu 18.04 LTS 64bit^* with minimum 2GB memory.

Installing required packages

Please login and perform the following commands:

$ sudo apt-get install build-essential
$ sudo apt-get install qtcreator
$ sudo apt-get install qt5-default
$ sudo apt-get install qt5-doc
$ sudo apt-get install qt5-doc-html qtbase5-doc-html
$ sudo apt-get install qtbase5-examples

Installing cross toolchain

Please download cross compiler toolchain first. Then execute the following command to unzip the cross compiler tool to the /opt directory

$ sudo tar -zxf rk3399_risc_toolchain.tar.gz -C /opt

Working within QtCreator

Starting the QtCreator

$ qtcreator

The QtCreator's main window shows up.
Check QtCreator's version by using "Help" -> "About Qt Creator".

Configuring the Cross-Compiler Options

Bring up the options dialog using "Tools" -> "Options..."
Select the "Devices" page on the left, and click "Add..."
Select "Generic Linux Device" and click "Start Wizard".
Specify proper settings and click "Next>"
Click "Finish"
Device test finished successfully. Click "Close".

If device test failed, please go back to specify proper settings.

(It is necessary to set a blank password at least, null password does not work.)

(It means device's IP is incorrect or some network issues occured.)
Click "Apply"
Select the "Build & Run" page on the left, switch to "Compilers" tab, drop down "Add" menu and choose "GCC-->C++".
Name the compiler as "RK G++"
Click "Browse..." to select "/opt/rk3399_risc/buildroot/output/rockchip_rk3399/host/bin/aarch64-buildroot-linux-gnu-g++"
Click "Apply"
Switch to the "Debuggers" tab
Click "Add"
Name the debugger as "RK GDB"
Click "Browse..." to select "/opt/rk3399_risc/buildroot/output/rockchip_rk3399/host/bin/aarch64-buildroot-linux-gnu-gdb"
Click "Apply"
Switch to the "Qt Versions" tab.
Check if the "Qt 5.12.2 (host)" is auto detected in "Manual" item ?

If not, click "Add..." to choose the proper qmake.
Click "Apply"
Switch to the "Kits" tab.
Click "Add".
Name the kit as "RK toolchain"
Specify the correct "Device Tpye", "Compiler", "Debugger" and "Qt version"
Click "Browse..." to select "/opt/rk3399_risc/buildroot/output/rockchip_rk3399/host/aarch64-buildroot-linux-gnu/sysroot" as sysroot
Click Apply
Click OK to finalize the configuration.
Invoke the options dialog again to make sure the "iMX6 toolchain" is default kit.

Creating the Project

Bring up "New" dailog using "File" -> "New File or Project..."
Select "Applications" -> 'Qt Widgets Application"
Click "Choose..."
Use "Hello" as name
Create in "/mnt/sda1/work/qt/qt_PJ"
Click "Next"
Check "RK toolchain"
Click "Next".
Use default settings for "Class Information"
Click "Next"
Use default settings for "Project Management"
Click "Finish"
Double click "Hello.pro" to switch to editor window
In new project it is necessary to add following two lines into qt project file.
target.path = . INSTALLS += target
Press "Ctrl+S" to save file.
Double click "mainwindow.ui" to switch to Design mode
Drag & drop one Label widget on main form, use property editor on the right side to change text and font size
Save all project files using "File" -> "Save All"