Question

我正在尝试同时打开多个文件（随机数量的文件）并将其文本流存储在qlist中，以便在其他代码中使用：

QList<QTextStream> files;
QList<QString> fnames;
fnames.append("file1.txt");
fnames.append("file2.txt");
// ..and so on with random iterations

// collect qtextsrams into qlist
foreach (QString file, fnames) {
        QFile f(file);
        f.open(QIODevice::ReadOnly);
        QTextStream textStream(&f);
        files2.append(&textStream);
}

// use qtextstreams in a loop
QList<QTextStream>::iterator i;
for (i = files.begin(); i != files.end(); ++i) {
      qDebug() << i->readLine();
}

所以我有一个错误：

/make debug 
make -f Makefile.Debug
make[1]: Entering directory `/home/pixx/Workspace/collocs'
g++ -c -pipe -g -Wall -W -D_REENTRANT -DQT_GUI_LIB -DQT_CORE_LIB -DQT_SHARED -I/usr/share/qt4/mkspecs/linux-g++ -I. -I/usr/include/qt4/QtCore -I/usr/include/qt4/QtGui -I/usr/include/qt4 -Idebug -o debug/main.o main.cpp
main.cpp: In function ‘int main(int, char**)’:
main.cpp:128: error: no matching function for call to ‘QList<QTextStream>::append(QTextStream*)’
/usr/include/qt4/QtCore/qlist.h:493: note: candidates are: void QList<T>::append(const T&) [with T = QTextStream]
/usr/include/qt4/QtCore/qlist.h:819: note:                 void QList<T>::append(const QList<T>&) [with T = QTextStream]
main.cpp:117: warning: unused variable ‘cc’
In file included from /usr/include/qt4/QtCore/QList:1,
                 from main.cpp:1:
/usr/include/qt4/QtCore/qtextstream.h: In member function ‘void QList<T>::node_copy(QList<T>::Node*, QList<T>::Node*, QList<T>::Node*) [with T = QTextStream]’:
/usr/include/qt4/QtCore/qlist.h:695:   instantiated from ‘void QList<T>::detach_helper(int) [with T = QTextStream]’
/usr/include/qt4/QtCore/qlist.h:709:   instantiated from ‘void QList<T>::detach_helper() [with T = QTextStream]’
/usr/include/qt4/QtCore/qlist.h:126:   instantiated from ‘void QList<T>::detach() [with T = QTextStream]’
/usr/include/qt4/QtCore/qlist.h:254:   instantiated from ‘QList<T>::iterator QList<T>::begin() [with T = QTextStream]’
main.cpp:133:   instantiated from here
/usr/include/qt4/QtCore/qtextstream.h:258: error: ‘QTextStream::QTextStream(const QTextStream&)’ is private
/usr/include/qt4/QtCore/qlist.h:386: error: within this context
/usr/include/qt4/QtCore/qtextstream.h:258: error: ‘QTextStream::QTextStream(const QTextStream&)’ is private
/usr/include/qt4/QtCore/qlist.h:399: error: within this context
make[1]: Leaving directory `/home/pixx/Workspace/collocs'
make[1]: *** [debug/main.o] Error 1
make: *** [debug] Error 2

我应该修理什么？我知道这是一个非常简单的问题，但我找不到谷歌的正确查询:(

Answer 1

第一个错误，即“没有用于调用'QList :: append（QTextStream *）'的匹配函数'”是由你使用＆amp;这一行的运营商：

files2.append(&textStream);

您的列表应该由QTextStream对象组成，而不是指向QTextStream对象的指针。

但真正的问题更深层次。要将对象放入列表，对象必须具有复制构造函数。 QTextStream没有任何内容，因为不清楚同一文本流的不同副本应该如何协同工作。我建议你创建一个指向文本流的指针列表，如“QList”。当然，在这种情况下，当不再需要它们时，不要忘记处理它们的破坏：

foreach (QTextStream *cur, files) delete cur;

如果你需要在代码的不同部分之间传递这个列表，制作它的多个副本等等，你可能需要智能指针（QSharedPointer），但我很难想到你的任务在哪里需要对文本流进行处理。

Answer 2

我找到了解决方案，感谢Septagram的想法！ QList文件2; //要合并的文件列表

QList<QTextStream> files;
QList<QString> fnames;
fnames.append("file1.txt");
fnames.append("file2.txt");
// ..and so on with random iterations
QList<QFile *> files2; // file list to merge
QList<QTextStream *> files3;
foreach (QString file, files) {
    files2.append(new QFile(file)); // create file obj
    files2.last()->open(QIODevice::ReadOnly); // open file
    files3.append(new QTextStream(files2.last())); // create textstream
}

QList< QTextStream * >::iterator i3;
for (i3 = files3.begin(); i3 != files3.end(); ++i3) {
      qDebug() << (*i3)->readLine();
}

QT：将QTextStream存储在QList中

2 个答案: