qt心得（QT experience）.docVIP

qt心得（QT experience） Qt experience.Txt File read and write 1. required header files #include qstring.h #include qfile.h #include qtextstream.h #include qtextcodec.h 2. about QString: String lists can be handled using the QStringList class. You can use the QStringList:: split () to take a string into a list of strings, and you can use the QStringList:: join () to string a string into a list of connection using symbols at random intervals. You can also use QStringList:: grep () to obtain a list of strings containing a specific substring or containing a specific regex from a list of strings. 3. about QFile: When you arrive at the end of the file, the return value of EOF () is not 0, otherwise 0; The QFile class is an input / output device for operating files. QFile is an input / output device for reading and writing binary and text files. QFile can be used by itself, but it will be more convenient if used with QDataStream or QTextStream. Filenames can usually be passed by constructors, but they can also be set with setName (). You can check whether a file exists by exists (), and you can remove a file by remove (). The file can be opened with open (), closed with close (), and refreshed with flush (). Data can usually be read and written using QDataStream or QTextStream, but you can also use readBlock () and readLine () to read, and use writeBlock () to write. QFile also supports getch (), ungetch () and Putch (). Size () returns the size of the file. You can get the current file location or move to a new file location by using the at () function. If you arrive at the end of the file, atEnd () returns true. Handle () returns the file handle. Here is a snippet of code that uses QTextStream to read a text file line by line. It will print each line with a line number. QStringList lines; QFile file (file.txt); If (file.open (IO_ReadOnly)) { QTextStream stream (file); QString line; Int n = 1; While (... Stream.eof ()) { Line = (stream.readLine); / / does not include a line o