qte终于移植成功，但是在交叉编译自己写的程序是总是提示有错误，错误如下：In file included from main.cpp:3:
./database.h:3:23: QSqlDatabase: No such file or directory
./database.h:4:20: QSqlQuery: No such file or directory
In file included from main.cpp:3:
./database.h: In function `bool createConnection()':
./database.h:8: error: `QSqlDatabase' was not declared in this scope
./database.h:8: error: expected `;' before "db"
./database.h:9: error: `db' was not declared in this scope
./database.h:8: warning: unused variable 'QSqlDatabase'
make: *** [main.o] 错误
提示没有这两个文件或目录？明明在我的include里面怎么会没有?我想尽一切办法，又是该边境变量，又是删除编译文件重新编译，最后还是不行，我一遍一遍的查看include目录，最后发现错误提示的两个文件在include/QtSql/下面所以我就把程序的包含文件目录该了一下原来为：#include<QSqlDatabase>，#include<QSqlQuery>改过后为：#include<QtSql/QSqlDatabase>，#include<QtSql/QSqlQuery>就是在原来的基础上增加一个目录前缀，这样问题就解决了，这个编译通过，但是下面又出现了错误，错误如下：songlist.cpp:6:20: QSqlQuery: No such file or directory
songlist.cpp:12: error: `songlist' has not been declared
songlist.cpp:12: error: ISO C++ forbids declaration of `songlist' with no type
songlist.cpp: In function `int songlist(QWidget*)':
songlist.cpp:12: error: only constructors take base initializers
songlist.cpp:16: error: `ui' was not declared in this scope
songlist.cpp:16: error: invalid use of `this' in non-member function
songlist.cpp:20: error: `model' was not declared in this scope
songlist.cpp:20: error: `QSqlTableModel' has not been declared
songlist.cpp:20: error: invalid use of `this' in non-member function
songlist.cpp:31: error: `model2' was not declared in this scope
songlist.cpp:31: error: `QSqlTableModel' has not been declared
songlist.cpp:31: error: invalid use of `this' in non-member function
songlist.cpp: At global scope:
songlist.cpp:46: error: expected constructor, destructor, or type conversion before '::' token
songlist.cpp:51: error: `songlist' is not a class or namespace
songlist.cpp: In function `void changeEvent(QEvent*)':
songlist.cpp:53: error: cannot call member function `virtual void QWidget::changeEvent(QEvent*)' without object
songlist.cpp:56: error: `ui' was not declared in this scope
songlist.cpp:56: error: invalid use of `this' in non-member function
songlist.cpp:56: warning: unused variable 'ui'
songlist.cpp: At global scope:
songlist.cpp:63: error: `songlist' is not a class or namespace
songlist.cpp: In function `void on_pushButton_clicked()':
songlist.cpp:65: error: `ui' was not declared in this scope
songlist.cpp:70: error: `model' was not declared in this scope
songlist.cpp:80: error: `model2' was not declared in this scope
songlist.cpp:65: warning: unused variable 'ui'
songlist.cpp: At global scope:
songlist.cpp:87: error: `songlist' is not a class or namespace
songlist.cpp: In function `void on_pushButton_4_clicked()':
songlist.cpp:89: error: `ui' was not declared in this scope
songlist.cpp:90: error: `model2' was not declared in this scope
songlist.cpp:92: error: `Dir' was not declared in this scope
songlist.cpp:93: error: `prefix' was not declared in this scope
songlist.cpp:94: error: `PATH' was not declared in this scope
songlist.cpp:97: error: `play1' was not declared in this scope
songlist.cpp:97: warning: unused variable 'play1'
songlist.cpp: At global scope:
songlist.cpp:103: error: `songlist' is not a class or namespace
songlist.cpp: In function `void on_pushButton_3_clicked()':
songlist.cpp:105: error: `ui' was not declared in this scope
songlist.cpp:106: error: `model2' was not declared in this scope
songlist.cpp:105: warning: unused variable 'ui'
songlist.cpp: At global scope:
songlist.cpp:110: error: `songlist' is not a class or namespace
songlist.cpp: In function `void on_pushButton_2_clicked()':
songlist.cpp:115: error: invalid use of `this' in non-member function
database.h: At global scope:
database.h:7: warning: 'bool createConnection()' defined but not used
make: *** [songlist.o] 错误
交叉编译真是让人头大啊！从错误开始的地方找，添加头目录，发现问题还是没有解决，于是就查看songlist.h发现里面什么东西都没了，还提示任何的改动都可能造成文件内容丢失，于是就重新建立了一个工程，继续交叉编译，前面的问题都解决了 ，但是又出现了新的错误，错误如下：main.o: In function `main':
main.cpp:(.text+0x210): undefined reference to `QSqlQuery::~QSqlQuery()'
main.cpp:(.text+0x220): undefined reference to `QSqlDatabase::~QSqlDatabase()'
main.cpp:(.text+0x794): undefined reference to `QSqlDatabase::addDatabase(QString const&, QString const&)'
main.cpp:(.text+0x858): undefined reference to `QSqlDatabase::~QSqlDatabase()'
main.cpp:(.text+0xbac): undefined reference to `QSqlDatabase::setDatabaseName(QString const&)'
main.cpp:(.text+0xc48): undefined reference to `QSqlDatabase::open()'
main.cpp:(.text+0xcf0): undefined reference to `QSqlQuery::~QSqlQuery()'
main.cpp:(.text+0xd00): undefined reference to `QSqlDatabase::~QSqlDatabase()'
main.cpp:(.text+0xd68): undefined reference to `QSqlDatabase::QSqlDatabase()'
main.cpp:(.text+0xd80): undefined reference to `QSqlQuery::QSqlQuery(QString const&, QSqlDatabase)'
main.cpp:(.text+0xd90): undefined reference to `QSqlDatabase::~QSqlDatabase()'
main.cpp:(.text+0xe98): undefined reference to `QSqlQuery::exec(QString const&)'
main.cpp:(.text+0xef8): undefined reference to `QSqlDatabase::defaultConnection'
main.cpp:(.text+0xf90): undefined reference to `QSqlQuery::exec(QString const&)'
main.cpp:(.text+0x1038): undefined reference to `QSqlQuery::exec(QString const&)'
main.cpp:(.text+0x10e0): undefined reference to `QSqlQuery::exec(QString const&)'
main.cpp:(.text+0x1188): undefined reference to `QSqlQuery::exec(QString const&)'
main.cpp:(.text+0x1230): undefined reference to `QSqlQuery::exec(QString const&)'
main.o:main.cpp:(.text+0x12d8): more undefined references to `QSqlQuery::exec(QString const&)' follow
songlist.o: In function `songlist::songlist(QWidget*)':
songlist.cpp:(.text+0x1ac): undefined reference to `QSqlQuery::~QSqlQuery()'
songlist.cpp:(.text+0x47c): undefined reference to `QSqlDatabase::~QSqlDatabase()'
songlist.cpp:(.text+0x5b0): undefined reference to `QSqlDatabase::QSqlDatabase()'
songlist.cpp:(.text+0x5d8): undefined reference to `QSqlTableModel::QSqlTableModel(QObject*, QSqlDatabase)'
songlist.cpp:(.text+0x5f4): undefined reference to `QSqlDatabase::~QSqlDatabase()'
songlist.cpp:(.text+0x7c0): undefined reference to `QSqlDatabase::QSqlDatabase()'
songlist.cpp:(.text+0x7e8): undefined reference to `QSqlTableModel::QSqlTableModel(QObject*, QSqlDatabase)'
songlist.cpp:(.text+0x804): undefined reference to `QSqlDatabase::~QSqlDatabase()'
songlist.cpp:(.text+0x8cc): undefined reference to `QSqlQueryModel::query() const'
songlist.cpp:(.text+0x9d0): undefined reference to `QSqlQuery::~QSqlQuery()'
songlist.o: In function `songlist::songlist(QWidget*)':
songlist.cpp:(.text+0xbb8): undefined reference to `QSqlQuery::~QSqlQuery()'
songlist.cpp:(.text+0xe88): undefined reference to `QSqlDatabase::~QSqlDatabase()'
songlist.cpp:(.text+0xfbc): undefined reference to `QSqlDatabase::QSqlDatabase()'
songlist.cpp:(.text+0xfe4): undefined reference to `QSqlTableModel::QSqlTableModel(QObject*, QSqlDatabase)'
songlist.cpp:(.text+0x1000): undefined reference to `QSqlDatabase::~QSqlDatabase()'
songlist.cpp:(.text+0x11cc): undefined reference to `QSqlDatabase::QSqlDatabase()'
songlist.cpp:(.text+0x11f4): undefined reference to `QSqlTableModel::QSqlTableModel(QObject*, QSqlDatabase)'
songlist.cpp:(.text+0x1210): undefined reference to `QSqlDatabase::~QSqlDatabase()'
songlist.cpp:(.text+0x12d8): undefined reference to `QSqlQueryModel::query() const'
songlist.cpp:(.text+0x13dc): undefined reference to `QSqlQuery::~QSqlQuery()'
songlist.o: In function `songlist::on_pushButton_clicked()':
songlist.cpp:(.text+0x2f38): undefined reference to `QSqlTableModel::submitAll()'
songlist.o: In function `songlist::on_pushButton_4_clicked()':
songlist.cpp:(.text+0x43d0): undefined reference to `QSqlTableModel::submitAll()'
songlist.o: In function `songlist::on_pushButton_3_clicked()':
songlist.cpp:(.text+0x47b8): undefined reference to `QSqlTableModel::submitAll()'
collect2: ld returned 1 exit status
make: *** [SKTV] 错误
这样错误在交叉编译QTE时，出现了一个类似的，但是我重新解压再编译时却没有了 ，我在网上也没找到类似的问题，所以我只好再重新编译了，相同的错误还是出现，先静下心来想想，一夜没有睡好！
终于解决了，问题终于解决了。问题原因：由于交叉编译是使用qte的qmake -project手动建立的工程文件，无法自动判断是否包含数据库，所以我们如果使用了数据库既要手动在工程文件的最后添加一句话，QT +=sql这样问题就迎刃而解了，困扰了我好几天的错误，也是最关键的错误，如果无法解决，整个程序将无法编译和移植！啊，松了一口气！