c++ - 编译Qt教程时"undefined symbols for architecture"链接器错误

Question

尝试在 Mac 上编译我的 QT 应用程序时出现错误。我跟着这个tutorial所有代码都在页面底部。

当我构建项目时，我得到以下信息:

Undefined symbols for architecture x86_64:
  "DiagramItem::addArrow(Arrow*)", referenced from:
      DiagramScene::mouseReleaseEvent(QGraphicsSceneMouseEvent*) in diagramscene.o
  "DiagramScene::setItemType(DiagramItem::DiagramType)", referenced from:
      MainWindow::buttonGroupClicked(int) in mainwindow.o
      DiagramScene::qt_static_metacall(QObject*, QMetaObject::Call, int, void**) in moc_diagramscene.o
  "DiagramScene::setTextColor(QColor const&)", referenced from:
      MainWindow::textButtonTriggered() in mainwindow.o
  "DiagramScene::setMode(DiagramScene::Mode)", referenced from:
      MainWindow::buttonGroupClicked(int) in mainwindow.o
      MainWindow::pointerGroupClicked(int) in mainwindow.o
      MainWindow::itemInserted(DiagramItem*) in mainwindow.o
      MainWindow::textInserted(QGraphicsTextItem&) in mainwindow.o
      DiagramScene::qt_static_metacall(QObject*, QMetaObject::Call, int, void**) in moc_diagramscene.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [DiagramScene.app/Contents/MacOS/DiagramScene] Error 1
18:41:52: The process "/usr/bin/make" exited with code 2.
Error while building/deploying project DiagramScene (kit: Desktop)
When executing step 'Make'

有人以前见过这个或有什么建议吗？

提前致谢。 :)

Answer 1

链接器准确地告诉您发生了什么。没有为列出的方法提供实现，即:

• DiagramItem::addArrow(箭头*)
• DiagramScene::setItemType(DiagramItem::DiagramType)
• DiagramScene::setTextColor(QColor const&)
• DiagramScene::setMode(DiagramScene::Mode)

只需编写这些方法的实现。如果您从帮助页面复制粘贴代码，该示例可能不完整。