Ubuntu20.04 安装qt5.12.8

首先设置清华源，/etc/apt/sources.list

deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal main restricted universe multiverse
deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-updates main restricted universe multiverse
deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-backports main restricted universe multiverse
deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-security main restricted universe multiverse

2. 下载qt

sudo apt install qtbase5-dev qtchooser qt5-qmake qtbase5-doc-html libqt5webkit5 libqt5webengine5 libqt5sql5 libqt5sql5-sqlite qml-module-qtquick-controls qml-module-qtquick-dialogs qml-module-qtquick-layouts qml-module-qtquick-window2 qml-module-qtquick2 qml-module-qtquick-xmllistmodel qml-module-qtgraphicaleffects qml-module-qtmultimedia qml-module-qtquick2 qml-module-qtquick-privatewidgets qml-module-qttest qmlscene qmlplugindump
  500  sudo apt install qtbase5-dev qtchooser qt5-qmake qtbase5-doc-html libqt5webkit5 libqt5webengine5 libqt5sql5 libqt5sql5-sqlite qml-module-qtquick-controls qml-module-qtquick-dialogs qml-module-qtquick-layouts qml-module-qtquick-window2 qml-module-qtquick2 qml-module-qtquick-xmllistmodel qml-module-qtgraphicaleffects qml-module-qtmultimedia qml-module-qtquick2 qml-module-qtquick-privatewidgets qml-module-qttest qmlscene qmlplugindump  –download-only
  501  sudo apt install qtbase5-dev qtchooser qt5-qmake qtbase5-doc-html libqt5webkit5 libqt5webengine5 libqt5sql5 libqt5sql5-sqlite qml-module-qtquick-controls qml-module-qtquick-dialogs qml-module-qtquick-layouts qml-module-qtquick-window2 qml-module-qtquick2 qml-module-qtquick-xmllistmodel qml-module-qtgraphicaleffects qml-module-qtmultimedia qml-module-qtquick2 qml-module-qtquick-privatewidgets qml-module-qttest qmlscene qtdeclarative5-dev  –download-only

3.下载qtcreator

sudo apt-get install qtcreator qt5-default –download-only

4. 最后进入到 /var/cache/apt/archives 里面，执行 sudo dpkg -i *.deb 完成安装