前言
在Linux系统上会遇到Qt开发的程序无法输入中文的情况，原因就是因为输入法框架是采用的fcitx，而不是ibus，Qt默认只支持ibus输入法框架。在Qt/5.15.2/gcc_64/plugins/platforminputcontexts/路径下可以看到，只有libibusplatforminputcontextplugin.so，没有libfcitxplatforminputcontextplugin.so。而本文的目的就是编译出libfcitxplatforminputcontextplugin.so动态库，使其支持fcitx输入法框架，从而支持输入中文。
下载源代码
git clone https://github.com/fcitx/fcitx-qt5注意，是fcitx-qt5、fcitx-qt5、fcitx-qt5，fcitx 组织下还有一个容易混淆的仓库，请仔细区分。
构建编译fcitx-qt5
首先需要安装必备的依赖环境：
sudo apt install extra-cmake-modules在这之前，最好设置Qt的环境变量：
export PATH=$PATH:/home/leo/Qt/5.15.2/bin/不设置的话也行，可以 cmake 手动指定Qt目录。
如果你是 Qt 6，那么还需要修改一下fcitx-qt5的CMakeLists.txt文件：
option(ENABLE_QT4 "Enable Qt 4" On)option(ENABLE_QT5 "Enable Qt 5" Off)option(ENABLE_QT6 "Enable Qt 6" On)option(BUILD_ONLY_PLUGIN "Build only plugin" Off)option(BUILD_STATIC_PLUGIN "Build plugin as static" Off)option(WITH_FCITX_PLUGIN_NAME "Enable plugin name with fcitx" On)将ENABLE_QT5改为off，ENABLE_QT6改为on
然后创建一个build目录：
mkdir buildcd build执行cmake命令
cmake .. -DENABLE_LIBRARY=false执行make
make在build目录下的qt5/platforminputcontext就有需要的libfcitx5platforminputcontextplugin.so插件动态库了。
安装(可选)
make install 命令会将插件装到指定qt环境下的plugins目录下
$ make install[4%] Automatic MOC for target fcitxplatforminputcontextplugin[4%] Built target fcitxplatforminputcontextplugin_autogen[100%] Built target fcitxplatforminputcontextpluginInstall the project...-- Install configuration: ""-- Installing: /home/leo/Qt/5.15.2/plugins/platforminputcontexts/libfcitxplatforminputcontextplugin.so-- Set runtime path of "/home/leo/Qt/5.15.2/plugins/platforminputcontexts/libfcitxplatforminputcontextplugin.so" to ""也可自行将动态库拷贝到对应路径下或者自己的Qt程序打包路径下。
错误解决
找不到 FcitxConfig.cmake
CMake Error at CMakeLists.txt:36 (find_package):By not providing "FindFcitx.cmake" in CMAKE_MODULE_PATH this project hasasked CMake to find a package configuration file provided by "Fcitx", butCMake did not find one.Could not find a package configuration file provided by "Fcitx" (requestedversion 4.2.8) with any of the following names:FcitxConfig.cmakefcitx-config.cmakeAdd the installation prefix of "Fcitx" to CMAKE_PREFIX_PATH or set"Fcitx_DIR" to a directory containing one of the above files. If "Fcitx"provides a separate development package or SDK, be sure it has been installed. -- Configuring incomplete, errors occurred!See also "/media/veracrypt/mythware/gerrit/QT/ClassroomManagement/ClassroomManagement/Submodules/fcitx/fcitx-qt5/build/CMakeFiles/CMakeOutput.log".解决方案
命令行增加 “-DENABLE_LIBRARY=false” 参数
cmake .. -DENABLE_LIBRARY=false找不到 ECMConfig.cmake
CMake Error at CMakeLists.txt:8 (find_package):Could not find a package configuration file provided by "ECM" (requestedversion 1.4.0) with any of the following names:ECMConfig.cmakeecm-config.cmakeAdd the installation prefix of "ECM" to CMAKE_PREFIX_PATH or set "ECM_DIR"to a directory containing one of the above files. If "ECM" provides aseparate development package or SDK, be sure it has been installed.-- Configuring incomplete, errors occurred!See also "/home/shana/fcitx-qt5/build/CMakeFiles/CMakeOutput.log".解决方案:
安装extra-cmake-modules包:
sudo apt install extra-cmake-modules找不到 Qt5Config.cmake
解决方案:
命令行增加-DQt5_DIR=[Qt目录]/lib/cmake/Qt5参数
cmake .. -DENABLE_LIBRARY=false -DQt5_DIR=[Qt目录]/lib/cmake/Qt5