如何隐藏临时搜索栏？

Question

我有一个包含浏览器的窗口.Up是一个工具栏.在窗口的底部是一个搜索栏.搜索栏有一个关闭按钮[x].当用户单击关闭按钮时,我希望该栏消失.我希望只有当用户按下CTRL + F时才显示该栏.我尝试使用.hide()命令连接关闭的butoon,但应用程序崩溃.我需要帮助.

的.cpp

DocumentationWin::DocumentationWin (QWidget * parent){
    docs = new QTextBrowser( this );

    //Prepare toolbar
    toolbar = new QToolBar( this );
    //add stuff to toolbar


    //Prepare footer bar
    searchlabel = new QLabel(tr("Find in page:"),this);
    resultslabel = new QLabel("",this);
    searchinput = new QLineEdit();

    findprev = new QToolButton(this);
    findprev->setArrowType(Qt::UpArrow);
    connect(findprev, SIGNAL(clicked()), this, SLOT (clickFindPrev()));
    findnext = new QToolButton(this);
    findnext->setArrowType(Qt::DownArrow);
    connect(findnext, SIGNAL(clicked()), this, SLOT (clickFindNext()));

    QStyle *style = qApp->style();
    QIcon closeIcon = style->standardIcon(QStyle::SP_TitleBarCloseButton);
    QPushButton *closeButton = new QPushButton(this);
    closeButton->setIcon(closeIcon);
    closeButton->setFlat(true);
    connect(closeButton, SIGNAL(clicked()), this, SLOT (clickCloseFind()));
    QWidget *bottom = new QWidget;
    QHBoxLayout *footer = new QHBoxLayout();
    casecheckbox = new QCheckBox(tr("Case sensitive"),this);

    footer->setContentsMargins(5,5,5,5);
    footer->addWidget(searchlabel);
    footer->addSpacing(3);
    footer->addWidget(searchinput);
    footer->addWidget(findprev);
    footer->addWidget(findnext);
    footer->addSpacing(10);
    footer->addWidget(casecheckbox);
    footer->addSpacing(10);
    footer->addWidget(resultslabel);
    footer->addStretch(1);
    footer->addWidget(closeButton);
    bottom->setLayout(footer);


    //Prepare main layout
    layout = new QVBoxLayout;
    layout->setContentsMargins(0,0,0,0);
    layout->setSpacing(0);
    layout->addWidget(toolbar);
    layout->addWidget(docs);
    layout->addWidget(bottom);

    this->setLayout(layout);
    this->show();
}


void DocumentationWin::clickCloseFind(){
    bottom->hide();
}

.H

class DocumentationWin : public QDialog
{
  Q_OBJECT
  public:
    DocumentationWin(QWidget * parent);

  protected:
    virtual void keyPressEvent(QKeyEvent *);

  private slots:
    void clickCloseFind();

  private:
    QVBoxLayout* layout;
    QToolBar* toolbar;
    QTextBrowser* docs;
    QBoxLayout* footer;
    QLabel *searchlabel;
    QLabel *resultslabel;
    QLineEdit *searchinput;
    QToolButton *findprev;
    QToolButton *findnext;
    QCheckBox *casecheckbox;
    QWidget *bottom;
    QPushButton *closeButton;
};

Answer 1

啊,隐藏成员的局部变量的经典案例.关于这一点,有很多相同的问题.这是错的:

QWidget *bottom = new QWidget;

你要:

bottom = new QWidget;

你会遇到这些问题总是因为你动态分配所有的小部件 - 这是完全没必要的.

建议:

1. 按值保存子窗口小部件和布局,不要动态分配它们.

2. 不要将父级传递给由布局管理的窗口小部件.布局的每个小部件都将自动成为父级.

3. 不要多余打电话setLayout.A QLayout将小部件作为构造函数参数放置其子元素.

4. QWidget::hide() 是一个插槽.

5. 许多小部件将文本作为构造函数参数.

6. 如果你没有任何参数传递给new表达式中的构造函数,你可以删除括号(但我们试图避免这些):

   searchinput = new QLineEdit; // not QLineEdit();
   

7. 小部件通常不应该show()在构造时自己.没有Qt小部件那样做.这取决于小部件的用户.

8. C++使用构造语法重载方法调用语法.为了区分这两者,更喜欢统一初始化(Type{arg0, arg1, ...})而不是使用的旧语法().

以下是使用C++ 11时代码的外观.这可以使用Qt 4或Qt 5编译.如果你没有针对Qt 4,你应该使用新的连接语法.

正如您所看到的,没有一个显式的动态分配 - 当使用的类型是理智的时候,这就是C++ 11代码的外观.

// https://github.com/KubaO/stackoverflown/tree/master/questions/find-hide-38082794
#include <QtGui>
#if QT_VERSION >= QT_VERSION_CHECK(5,0,0)
#include <QtWidgets>
#endif

class DocumentationWin : public QDialog
{
   Q_OBJECT
public:
   explicit DocumentationWin(QWidget * parent = 0);
private:
   QVBoxLayout layout{this};
   QToolBar toolbar;
   QTextBrowser docs;
   QWidget bottom;
   QHBoxLayout footer{&bottom};
   QLabel searchlabel{tr("Find in page:")};
   QLabel resultslabel;
   QLineEdit searchinput;
   QToolButton findprev;
   QToolButton findnext;
   QCheckBox casecheckbox{tr("Case sensitive")};
   QPushButton closeButton;

   Q_SLOT void onFindPrev() {}
   Q_SLOT void onFindNext() {}
};

DocumentationWin::DocumentationWin(QWidget * parent) : QDialog(parent) {
   findprev.setArrowType(Qt::UpArrow);
   connect(&findprev, SIGNAL(clicked()), this, SLOT(onFindPrev()));
   findnext.setArrowType(Qt::DownArrow);
   connect(&findnext, SIGNAL(clicked()), this, SLOT(onFindNext()));

   auto style = qApp->style();
   auto closeIcon = style->standardIcon(QStyle::SP_TitleBarCloseButton);
   closeButton.setIcon(closeIcon);
   closeButton.setFlat(true);
   connect(&closeButton, SIGNAL(clicked(bool)), &bottom, SLOT(hide()));

   footer.setContentsMargins(5,5,5,5);
   footer.addWidget(&searchlabel);
   footer.addSpacing(3);
   footer.addWidget(&searchinput);
   footer.addWidget(&findprev);
   footer.addWidget(&findnext);
   footer.addSpacing(10);
   footer.addWidget(&casecheckbox);
   footer.addSpacing(10);
   footer.addWidget(&resultslabel);
   footer.addStretch(1);
   footer.addWidget(&closeButton);

   layout.setContentsMargins(0,0,0,0);
   layout.setSpacing(0);
   layout.addWidget(&toolbar);
   layout.addWidget(&docs);
   layout.addWidget(&bottom);
}

int main(int argc, char ** argv) {
   QApplication app{argc, argv};
   DocumentationWin win;
   win.show();
   return app.exec();
}

#include "main.moc"