QHBoxLayout 、QFormLayout 遍歷子部件，查找QLineEdit控件

布局如下：

QLineEdit * edit1 = new QLineEdit;
QLineEdit * edit2 = new QLineEdit;
QLineEdit * edit3 = new QLineEdit;
QLineEdit * edit4 = new QLineEdit;

QFormLayout * formLayout1 = new QFormLayout;
QFormLayout * formLayout2 = new QFormLayout;

formLayout1->addRow(QStringLiteral("編輯1"), edit1);
formLayout1->addRow(QStringLiteral("編輯2"), edit2);

formLayout2->addRow(QStringLiteral("編輯3"), edit3);
formLayout2->addRow(QStringLiteral("編輯4"), edit4);

QHBoxLayout * hLayout = new QHBoxLayout;
hLayout->addLayout(formLayout1);
hLayout->addLayout(formLayout2);

...
遍歷查找每一個布局，判斷QLineEdit輸入是否為空
foreach(auto formLayoutChild,  hLayout->children())
{
          QFormLayout * formLayout = qobject_cast<QFormLayout*>(formLayoutChild);
           if (formLayout != nullptr)
           {
                     int itemCount =  formLayout->count();
                      for(int itemIndex = 0; itemIndex < itemCount; itemIndex++)
                     {
                           QLayoutItem * item = formLayout->itemAt(itemIndex);
                           QLineEdit * lineEdit = qobject_cast<QLineEdit*>(item->widget());
                            if (lineEdit != nullptr)
                            {
                                     if (lineEdit->text().isEmpty())
                                     {
                                               return false;
                                     }
                             }   
                      }
           }
}
return true;