10_文件对话框.md

文件对话框

目录

• 文件对话框

QFileDialog::getOpenFileName()来获取需要打开的文件

QString getOpenFileName(QWidget * parent = 0,
 			const QString & caption = QString(),
 			const QString & dir = QString(),
 			const QString & filter = QString(),
			QString * selectedFilter = 0,
			Options options = 0)

• parent: 父窗口
• caption： 标题
• dir：打开时的目录
• filter： 过滤器。过滤器就是用于过滤特定的后缀名。如果我们使用“Image Files(.jpg * .png)”，则只能显示后缀名是 jpg 或者 png 的文件。如果需要多个过滤器，使用“;;”分割，比如“JPEG Files( .jpg);;PNG Files(* .png)”；
• selectedFilter: 默认选择的过滤器
• options：对话框的一些参数设定，比如只显示文件夹等等，它的取值是 enum QFileDialog::Option，每个选项可以使用 | 运算组合起来

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
{
    setWindowTitle(tr("Main Window"));
    openAction = new QAction(tr("&Open..."), this);
    openAction->setShortcut(QKeySequence::Open);
    openAction->setStatusTip(tr("Open an existing file"));
    connect(openAction, &QAction::triggered, this, &MainWindow::open);

    QMenu *file = this->menuBar() -> addMenu(tr("&File"));
    file->addAction(openAction);

    saveAction = new QAction(tr("&Save"));
    saveAction->setShortcut(QKeySequence::Save);
    saveAction->setStatusTip(tr("Save this file"));
    connect(saveAction, &QAction::triggered, this, &MainWindow::save);
    file->addAction(saveAction);

    QToolBar *toolBar = addToolBar(tr("&File"));
    toolBar->addAction(openAction);

   textEdit = new QTextEdit();
   setCentralWidget(textEdit);

   statusBar();

}
void MainWindow::open() {
    QString path = QFileDialog::getOpenFileName(this, tr("Open File"), ".", tr("Text Files(*.txt)"));

    if (!path.isEmpty()) {
        QFile file(path);
        if (!file.open(QIODevice::ReadOnly | QIODevice::Text)) {
            QMessageBox::warning(this, tr("Read File"), tr("Cannot open file:\n%1").arg(path));
            return;
        }
        QTextStream in(&file);
        textEdit->setText(in.readAll());
        file.close();
    } else {
        QMessageBox::warning(this, tr("Path"), tr("You did not select any file."));
    }
}

void MainWindow::save() {
   QString path = QFileDialog::getSaveFileName(this, tr("Open File"), ".", tr("Text Files(*.txt)"));

   if (!path.isEmpty()) {
       QFile file(path);
       if (!file.open(QIODevice::WriteOnly | QIODevice::Text)) {
           QMessageBox::warning(this, tr("Write File"), tr("Can not open file:\n%1").arg(path));
           return;
       }
       QTextStream out(&file);
       out << textEdit->toPlainText();
       file.close();
   } else {
       QMessageBox::warning(this, tr("Path"), tr("You did not select any file.\n"));
   }
}