引言
树莓派因其低功耗和高性价比的特点，在嵌入式系统开发中得到了广泛应用。Qt和ROS（Robot Operating System）分别是跨平台GUI开发框架和机器人操作系统。本文将详细介绍如何在树莓派上实现Qt与ROS的交叉编译，帮助开发者快速搭建开发环境。
环境准备
1. 树莓派系统安装
首先，确保你的树莓派上安装了适合的操作系统，如Raspbian。
2. 软件包安装
在树莓派上安装以下软件包：
sudo apt-get update
sudo apt-get install build-essential
sudo apt-get install cmake
sudo apt-get install git
sudo apt-get install qmake
sudo apt-get install ros-<version>-desktop-full
其中<version>为ROS的版本号，如kinetic、melodic等。
3. 环境配置
配置ROS环境变量：
echo "source /opt/ros/<version>/setup.bash" >> ~/.bashrc
source ~/.bashrc
Qt交叉编译环境搭建
1. 下载Qt源码
从Qt官网下载对应版本的源码：
wget http://download.qt.io/official_releases/qt/<version>/submodules/qtbase-everywhere-src-<version>.tar.xz
tar -xvf qtbase-everywhere-src-<version>.tar.xz
cd qtbase-everywhere-src-<version>
2. 配置交叉编译参数
创建一个config文件，配置交叉编译参数：
mkdir config
cd config
cat << EOF > config.pri
QT_CONFIG += core gui widgets network xml sql
CONFIG += cross_compile
QMAKE_CROSS_COMPILE = arm-linux-gnueabihf-
QMAKE_CXX = arm-linux-gnueabihf-g++
QMAKE_LINK = arm-linux-gnueabihf-g++
QMAKE_AR = arm-linux-gnueabihf-ar cqs
QMAKE_STRIP = arm-linux-gnueabihf-strip
QMAKE_STRIPFLAGS =
QMAKE_OBJCOPY = arm-linux-gnueabihf-objcopy
QMAKE_NM = arm-linux-gnueabihf-nm
QMAKE_RANLIB = arm-linux-gnueabihf-ranlib
QMAKE_STRIPFLAGS =
QT_QPA_FONTENGINE = freetype
QT_QPA_PLATFORM = linuxfb
QT_QPA_PLATFORM_PLUGIN_PATH = .
QT_QPA_PLATFORM_THEMES_PATH = .
QT_QPA_FONTDIR = .
QT_QPA_INPUT = evdev
QT_QPA_EVDEV,evdev = evdev
QT_QPA_EVDEV,evdev.CONFIG = evdev
QT_QPA_EVDEV,evdev.DEFINES += QPA_EVDEV
QT_QPA_EVDEV,evdev.SOURCES += evdev.cpp
QT_QPA_EVDEV,evdev.HEADERS += evdev.h
QT_QPA_EVDEV,evdev.TYPE = dll
QT_QPA_EVDEV,evdev.NAME = evdev
QT_QPA_EVDEV,evdev.INCLUDEPATH += .
QT_QPA_EVDEV,evdev.BIN = evdev
QT_QPA_EVDEV,evdev.CONFIG += no_install
EOF
3. 编译Qt
在config目录下执行以下命令进行编译：
cd ..
qmake -makefile
make -j4
sudo make install
ROS交叉编译环境搭建
1. 下载ROS源码
从ROS官网下载对应版本的源码：
git clone https://github.com/ros/rosdistro.git
cd rosdistro
rosdep init
rosdep update
rosdep install --from-source --ignore-src --rosdistro <version> -y
2. 配置交叉编译参数
创建一个config文件，配置交叉编译参数：
mkdir config
cd config
cat << EOF > config.pri
CONFIG += cross_compile
QMAKE_CROSS_COMPILE = arm-linux-gnueabihf-
QMAKE_CXX = arm-linux-gnueabihf-g++
QMAKE_LINK = arm-linux-gnueabihf-g++
QMAKE_AR = arm-linux-gnueabihf-ar cqs
QMAKE_STRIP = arm-linux-gnueabihf-strip
QMAKE_OBJCOPY = arm-linux-gnueabihf-objcopy
QMAKE_NM = arm-linux-gnueabihf-nm
QMAKE_RANLIB = arm-linux-gnueabihf-ranlib
QMAKE_STRIPFLAGS =
QT_QPA_FONTENGINE = freetype
QT_QPA_PLATFORM = linuxfb
QT_QPA_PLATFORM_PLUGIN_PATH = .
QT_QPA_PLATFORM_THEMES_PATH = .
QT_QPA_FONTDIR = .
QT_QPA_INPUT = evdev
QT_QPA_EVDEV,evdev = evdev
QT_QPA_EVDEV,evdev.CONFIG = evdev
QT_QPA_EVDEV,evdev.DEFINES += QPA_EVDEV
QT_QPA_EVDEV,evdev.SOURCES += evdev.cpp
QT_QPA_EVDEV,evdev.HEADERS += evdev.h
QT_QPA_EVDEV,evdev.TYPE = dll
QT_QPA_EVDEV,evdev.NAME = evdev
QT_QPA_EVDEV,evdev.INCLUDEPATH += .
QT_QPA_EVDEV,evdev.BIN = evdev
QT_QPA_EVDEV,evdev.CONFIG += no_install
EOF
3. 编译ROS
在config目录下执行以下命令进行编译：
cd ..
rosdep install --from-source --ignore-src --rosdistro <version> -y
cd ..
rosbuild make
总结
通过以上步骤，你可以在树莓派上轻松实现Qt与ROS的交叉编译。这将帮助你快速搭建开发环境，为后续的机器人开发打下坚实的基础。