This application failed to start because it could not find or load the Qt platform plugin "linuxfb"

你好！这里是风筝的博客，

欢迎和我一起交流。

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在ARM板子上执行QT程序的时候，发现错误：

This application failed to start because it could not find or load the Qt platform plugin "linuxfb"
in "/work/qt/qt_arm".

Available platform plugins are: linuxfb, minimal, offscreen, vnc.

Reinstalling the application may fix this problem.
Aborted

这是因为没有找到linuxfb插件引起的，在QT的安装路径下：plugins/platforms，里面就存在libqlinuxfb.so，我把整个交叉编译过的QT复制到板子上，设置好环境变量：
vi /etc/profile

export QTEDIR=/work/qt/qt_arm
export LD_LIBRARY_PATH=/work/qt/qt_arm/lib:$LD_LIBRARY_PATH
#export QT_QPA_GENERIC_PLUGINS=tslib
#export QT_QPA_FONTDIR=$QTEDIR/lib/fonts
export QT_QPA_PLATFORM_PLUGIN_PATH=$QTEDIR/plugins/
export QT_QPA_PLATFORM=linuxfb:fb=/dev/fb0:size=176x220:mmSize=22x27:offset=0x0:
export QT_PLUGIN_PATH=/work/qt/qt_arm/plugins/

重启之后发现问题依旧没有解决，这样子，只好借助工具查看了！
使用strace：
如果是glibc的话可以从ubuntu下把starce拷出来放到板子上，就可以运行。
或者从网上下载一个别人编译好的strace，直接下载下来用，这里我也放一个下载链接吧，文章末尾提供。
或者是自己去下载strace源码来编译安装得到执行文件。

把stace放到板子根文件系统的bin目录即可。

起初是以为真的找不到linuxfb.so导致的错误，
执行：strace ./hello 2>&1 | grep “linuxfb.so”
其中hello是我们的QT程序，发现：

lstat64("/work/qt/qt_arm/plugins/platforms/libqlinuxfb.so", {st_mode=S_IFREG|0755, st_size=721352, ...}) = 0
open("/work/qt/qt_arm/plugins/platforms/libqlinuxfb.so", O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 3

这表明是可以找到linuxfb.so的，并且成功打开了，那我们这个错误到底是什么呢？
直接执行：
strace ./hello
就会发现真正的错误是：

open("/work/qt/qt_arm/lib/libts-1.0.so.0", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No s                                                              uch file or directory)
open("tls/v7l/neon/vfp/libts-1.0.so.0", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such                                                               file or directory)
open("tls/v7l/neon/libts-1.0.so.0", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such fil                                                              e or directory)
open("tls/v7l/vfp/libts-1.0.so.0", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file                                                               or directory)
open("tls/v7l/libts-1.0.so.0", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or                                                               directory)
open("tls/neon/vfp/libts-1.0.so.0", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such fil                                                              e or directory)
open("tls/neon/libts-1.0.so.0", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or                                                               directory)
open("tls/vfp/libts-1.0.so.0", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or                                                               directory)
open("tls/libts-1.0.so.0", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or dire                                                              ctory)

也就是找不到libts-1.0.so.0
这个错误是因为，我交叉编译QT时，因为我没有触摸屏，所以我并没有管 libts 关于触摸这部分，所以导致不能找到libts-1.0.so.0。
最后我在交叉工具链上寻找libts-1.0.so：
find -name libts-1.0.so
找到后拷到板子的lib目录下即可