1. 替换下载源

        sudo vi /etc/apt/sources.list，替换为：

deb http://mirrors.aliyun.com/ubuntu-ports/ focal main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu-ports/ focal main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu-ports/ focal-security main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu-ports/ focal-security main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu-ports/ focal-updates main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu-ports/ focal-updates main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu-ports/ focal-proposed main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu-ports/ focal-proposed main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu-ports/ focal-backports main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu-ports/ focal-backports main restricted universe multiverse

2. 更新源

        sudo apt-get update

3. 安装qt-creator

sudo apt-get install build-essential
sudo apt-get install qtbase5-dev qtchooser qt5-qmake qtbase5-dev-tools
sudo apt-get install qtcreator

4. 食用

        在ARM ubuntu中运行QTcreator不需要配置qmake，使用默认的就行。