c++ - 不完整类型的无效使用/前向声明

Question

我一直在寻找关于这个问题的信息..但是我找到的解决方案都没有帮助我，我真的希望你能帮助我

• maintabholder.h:

  #ifndef MAINTABHOLDER_H
  #define MAINTABHOLDER_H
  
  #include <QMainWindow>
  
  namespace Ui {
  class MainTabHolder;
  }
  
  class MainTabHolder : public QMainWindow
  {
      Q_OBJECT
  
  public:
      explicit MainTabHolder(QWidget *parent = 0);
      ~MainTabHolder();
  
  private:
      Ui::MainTabHolder *ui;
  };
  #endif // MAINTABHOLDER_H
  

• maintabholder.cpp:

  #include "maintabholder.h"
  #include "ui_maintabholder.h"
  
  MainTabHolder::MainTabHolder(QWidget *parent) :
      QMainWindow(parent),
      ui(new Ui::MainTabHolder)
  {
      ui->setupUi(this);
  }
  
  MainTabHolder::~MainTabHolder()
  {
      delete ui;
  }
  

• 主要.cpp:

  #include "maintabholder.h"
  #include <QApplication>
  
  int main(int argc, char *argv[])
  {
      QApplication a(argc, argv);
      MainTabHolder w;
      w.show();
      return a.exec();
  }
  

• ui_maintabholder.h #ifndef UI_MAINTABHOLDER_H #define UI_MAINTABHOLDER_H

  #include <QtCore/QVariant>
  #include <QtWebKitWidgets/QWebView>
  #include <QtWidgets/QAction>
  #include <QtWidgets/QApplication>
  #include <QtWidgets/QButtonGroup>
  #include <QtWidgets/QHBoxLayout>
  #include <QtWidgets/QHeaderView>
  #include <QtWidgets/QPushButton>
  #include <QtWidgets/QSpacerItem>
  #include <QtWidgets/QTabWidget>
  #include <QtWidgets/QVBoxLayout>
  #include <QtWidgets/QWidget>
  
  QT_BEGIN_NAMESPACE
  
  class Ui_Form
  {
  public:
      QHBoxLayout *horizontalLayout;
      QTabWidget *tabWidget;
      QWidget *comicViewer;
      QWidget *comicSearcher;
      QVBoxLayout *verticalLayout;
      QHBoxLayout *horizontalLayout_2;
      QPushButton *pushButton;
      QSpacerItem *horizontalSpacer;
      QPushButton *pushButton_2;
      QWebView *webView;
  
      void setupUi(QWidget *Form)
      {
          if (Form->objectName().isEmpty())
              Form->setObjectName(QStringLiteral("Form"));
          Form->resize(531, 308);
          horizontalLayout = new QHBoxLayout(Form);
          horizontalLayout->setObjectName(QStringLiteral("horizontalLayout"));
          tabWidget = new QTabWidget(Form);
          tabWidget->setObjectName(QStringLiteral("tabWidget"));
                  comicViewer = new QWidget();
          comicViewer->setObjectName(QStringLiteral("comicViewer"));
          comicViewer->setCursor(QCursor(Qt::ArrowCursor));
          tabWidget->addTab(comicViewer, QString());
          comicSearcher = new QWidget();
          comicSearcher->setObjectName(QStringLiteral("comicSearcher"));
          verticalLayout = new QVBoxLayout(comicSearcher);
          verticalLayout->setObjectName(QStringLiteral("verticalLayout"));
          horizontalLayout_2 = new QHBoxLayout();
          horizontalLayout_2->setObjectName(QStringLiteral("horizontalLayout_2"));
          pushButton = new QPushButton(comicSearcher);
          pushButton->setObjectName(QStringLiteral("pushButton"));
  
          horizontalLayout_2->addWidget(pushButton);
  
          horizontalSpacer = new QSpacerItem(40, 20, QSizePolicy::Expanding, QSizePolicy::Minimum);
  
          horizontalLayout_2->addItem(horizontalSpacer);
  
          pushButton_2 = new QPushButton(comicSearcher);
          pushButton_2->setObjectName(QStringLiteral("pushButton_2"));
          pushButton_2->setEnabled(false);
  
          horizontalLayout_2->addWidget(pushButton_2);
  
  
          verticalLayout->addLayout(horizontalLayout_2);
  
          webView = new QWebView(comicSearcher);
          webView->setObjectName(QStringLiteral("webView"));
          webView->setUrl(QUrl(QStringLiteral("about:blank")));
  
          verticalLayout->addWidget(webView);
  
          tabWidget->addTab(comicSearcher, QString());
  
          horizontalLayout->addWidget(tabWidget);
  
  
          retranslateUi(Form);
  
          tabWidget->setCurrentIndex(1);
  
  
          QMetaObject::connectSlotsByName(Form);
      } // setupUi
  
      void retranslateUi(QWidget *Form)
      {
          Form->setWindowTitle(QApplication::translate("Form", "Form", 0));
          tabWidget->setTabText(tabWidget->indexOf(comicViewer), QApplication::translate("Form", "Comic Viewer", 0));
          pushButton->setText(QApplication::translate("Form", "Go to SubManga", 0));
          pushButton_2->setText(QApplication::translate("Form", "Download Comic", 0));
          tabWidget->setTabText(tabWidget->indexOf(comicSearcher), QApplication::translate("Form", "Search For Comics", 0));
      } // retranslateUi
  
  };
  
  namespace Ui {
      class Form: public Ui_Form {};
  } // namespace Ui
  
  QT_END_NAMESPACE
  
  #endif // UI_MAINTABHOLDER_H
  

编译错误是:

    [...]\maintabholder.cpp: In constructor 'MainTabHolder::MainTabHolder(QWidget*)':
    [...]\maintabholder.cpp:6:16: error: invalid use of incomplete type 'class Ui::MainTabHolder'
    In file included from [...]\maintabholder.cpp:1:0:
    [...]\maintabholder.h:7:7: error: forward declaration of 'class Ui::MainTabHolder'
    [...]\maintabholder.cpp:8:7: error: invalid use of incomplete type 'class Ui::MainTabHolder'
    In file included from [...]\maintabholder.cpp:1:0:
    [...]\maintabholder.h:7:7: error: forward declaration of 'class Ui::MainTabHolder'
    [...]\maintabholder.cpp: In destructor 'virtual MainTabHolder::~MainTabHolder()':
    [...]\maintabholder.cpp:13:12: warning: possible problem detected in invocation of delete operator: [enabled by default]
    [...]\maintabholder.cpp:13:12: warning: invalid use of incomplete type 'class Ui::MainTabHolder' [enabled by default]
    In file included from [...]\maintabholder.cpp:1:0:
    [...]\maintabholder.h:7:7: warning: forward declaration of 'class Ui::MainTabHolder' [enabled by default]
    [...]\maintabholder.cpp:13:12: note: neither the destructor nor the class-specific operator delete will be called, even if they are declared when the class is defined

你能帮忙吗？我会很感激...

Answer 1

您正在使用 Qt 的 uic 生成的文件；您应该通过例如检查构建输出和文件本身来验证此工具是否成功生成了文件。此外，检查它是否在 *.pro 文件中(即 maintabholder.h 被标记为由 uic 处理)。

我个人建议使用 multiple inheritance method对于用户界面:

// in maintabholder.h
// ...
#include "ui_maintabholder.h"

class MainTabHolder : public QMainWindow, public Ui::MainTabHolder
{
    // ...
};

使用更简单，如果您对 ui_*.h 文件有问题，错误会更明确。

您应该发布 ui_maintabholder.h。