Qt 文件操作

写文件

QFile file("filename.bin");
file.open(QIODevice::WriteOnly);
file.write(...);
file.close();

qint64 write(const char *data, qint64 len);
qint64 write(const char *data);
qint64 write(const QByteArray &data);

读文件

QFile file("filename.bin");
file.open(QIODevice::ReadOnly);
QByteArray data = file.readAll();
file.close();

qint64 read(char *data, qint64 maxlen);
QByteArray read(qint64 maxlen);
QByteArray readAll();
qint64 readLine(char *data, qint64 maxlen);
QByteArray readLine(qint64 maxlen = 0);

选择文件

QString filename;
filename = QFileDialog::getOpenFileName(this, "打开", "D:\", "图片文件(*.bmp *.jpg);;所有文件(*.*)");
filename = QFileDialog::getSaveFileName(this, "保存为", "D:\", "文本文档(*.txt);;所有文件(*.*)");

将函数的目录参数"D:\"改成NULL,首次打开文件选择窗口时默认为程序所在目录，后续打开文件选择就为上一次操作所在目录。

选择目录

QDir dirPath;
dirPath = QFileDialog::getExistingDirectory( this, "选择文件夹", "D:\");

文件信息

QFileInfo info(name);
bool exists = info.exists();
bool isDir = info.isDir();
bool isFile= info.isFile();
bool isRead= info.isReadable();
bool isWrite=info.isWritable();
bool isExec= info.isExecutable();