Prerequisites

Debian10(buster) is highly recommended OS to develop.

Installing required packages

Please login and perform the following commands:

$ sudo apt-get install -y build-essential 
$ sudo apt-get install -y qtcreator 
$ sudo apt-get install -y qt5-default 
$ sudo apt-get install -y qt5-doc 
$ sudo apt-get install -y qt5-doc-html qtbase5-doc-html 
$ sudo apt-get install -y qtbase5-examples 
$ sudo apt-get install -y qt5-qmake 
$ sudo apt-get install -y rsync
$ sudo apt-get install -y gcc-8-arm-linux-gnueabihf g++-8-arm-linux-gnueabihf
$ sudo apt-get install -y gcc-8-aarch64-linux-gnu g++-8-aarch64-linux-gnu

Link arm-linux-gnu*-8 to arm-linux-gnu* and aarch64-linux-gnu*-8 to aarch64-linux-gnu*:

$ sudo su
$ cd /usr/bin
$ for f in $(ls arm-linux-gnu*-8);do ln -sf $f $(echo $f|sed "s/-8//");done 
$ for f in $(ls aarch64-linux-gnu*-8);do ln -sf $f $(echo $f|sed "s/-8//");done
$ exit

Installing cross toolchain

Please download RK3288(Password: gm9i) and RK3399(Password: 0kkn) cross compiler toolchain first. Then execute the following command to unzip the cross compiler tool to the /opt directory

For RK3288

$ sudo rm -rf /opt/toolchain_Qt_V5.11.3/rk3288/
$ sudo mkdir -p /opt/toolchain_Qt_V5.11.3/rk3288/
$ sudo tar -zxf rk3288_toolchain_Qt_V5.11.3_*.tar.gz -C /opt/toolchain_Qt_V5.11.3/rk3288/

For RK3399

$ sudo rm -rf /opt/toolchain_Qt_V5.11.3/rk3399/ 
$ sudo mkdir -p /opt/toolchain_Qt_V5.11.3/rk3399/ 
$ sudo tar -zxvf rk3399_toolchain_Qt_V5.11.3_*.tar.gz -C /opt/toolchain_Qt_V5.11.3/rk3399/

Working within QtCreator

Use qtcreator to configure a complete build kit.

Config QtCreator ---- Qt Versions

Bring up the options dialog using "Tools" -> "Options..."
Select the "Build & Run" page on the left, switch to "Qt Versions" tab, and click "Add..."
Select qmake file
Select "/opt/toolchain_Qt_V5.11.3/rk3288/sysroot/qmake-debian-buster-armhf".

or

RK3399 Select "/opt/toolchain_Qt_V5.11.3/rk3399/sysroot/qmake".

or RK3399 Select "/opt/toolchain_Qt_V5.11.3/rk3399/sysroot/qmake-debian-buster-armhf "
Input Version name "Qt 5.11.3 (RK3288 )" or "Qt 5.11.3 (RK3399 )".

Config QtCreator ---- Kits

Bring up the options dialog using "Tools" -> "Options..."
Select the "Build & Run" page on the left, switch to "Kits" tab, and click "Add..."
Click "Add".

RK3288
Name: input "RK3288 toolchain"
Device Tpye: Select "Generic Linux Device"
Device: Select "RK3288"
Compiler: Select "GCC (C,arm 32bit in /usr/bin)" and "GCC (C++,arm 32bit in /usr/bin)"
Qt version: Select "Qt 5.11.3 (RK3288)"

RK3399

Name: input "RK3399 toolchain"
Device Tpye: Select "Generic Linux Device"
Device: Select "RK3399"
Compiler: Select "GCC (C,arm 64bit in /usr/bin)" and "GCC (C++,arm 64bit in /usr/bin)"
Qt version: Select "Qt 5.11.3 (RK3399)"

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"

Building the Project

Switch to "Projects" mode
Check if "build configuration" is set to "Debug".
Check if "Files to deploy" is correct
Set environment variable DISPLAY in QtCreator -> Projects -> Run -> Run Environment. The value of DISPLAY is obtained from the rk3399. For example, execute instruction echo $DISPLAY on RK3399.
Switch to "Edit" mode
Click "Build" using context menu of project "Hello"
The green "Build" bar means no error occured.
Press "Alt+4" to show "Compile Output".