moc_XXXX.o:(.data.rel.ro._ZTI12CalculatorUI[_ZTI12CalculatorUI]+0x10): undefined reference to `typeinfo for QWidget' collect2: error: ld returned 1 exit status make: *** [Makefile:144: myCalculator]

main.cpp:(.text.startup+0x22): undefined reference to `QApplication::QApplication(int&, char**, int)'

moc_CalculatorUI.o:(.data.rel.ro._ZTV12CalculatorUI[_ZTV12CalculatorUI]+0x1a0): undefined reference to `QWidget::inputMethodQuery(Qt::InputMethodQuery) const'
moc_CalculatorUI.o:(.data.rel.ro._ZTV12CalculatorUI[_ZTV12CalculatorUI]+0x1a8): undefined reference to `QWidget::focusNextPrevChild(bool)'
moc_CalculatorUI.o:(.data.rel.ro._ZTV12CalculatorUI[_ZTV12CalculatorUI]+0x1d0): undefined reference to `non-virtual thunk to QWidget::devType() const'
moc_CalculatorUI.o:(.data.rel.ro._ZTV12CalculatorUI[_ZTV12CalculatorUI]+0x1d8): undefined reference to `non-virtual thunk to QWidget::paintEngine() const'
moc_CalculatorUI.o:(.data.rel.ro._ZTV12CalculatorUI[_ZTV12CalculatorUI]+0x1e0): undefined reference to `non-virtual thunk to QWidget::metric(QPaintDevice::PaintDeviceMetric) const'
moc_CalculatorUI.o:(.data.rel.ro._ZTV12CalculatorUI[_ZTV12CalculatorUI]+0x1e8): undefined reference to `non-virtual thunk to QWidget::initPainter(QPainter*) const'
moc_CalculatorUI.o:(.data.rel.ro._ZTV12CalculatorUI[_ZTV12CalculatorUI]+0x1f0): undefined reference to `non-virtual thunk to QWidget::redirected(QPoint*) const'
moc_CalculatorUI.o:(.data.rel.ro._ZTV12CalculatorUI[_ZTV12CalculatorUI]+0x1f8): undefined reference to `non-virtual thunk to QWidget::sharedPainter() const'
moc_CalculatorUI.o:(.data.rel.ro+0x0): undefined reference to `QWidget::staticMetaObject'
collect2: error: ld returned 1 exit status
make: *** [Makefile:144: myCalculator] Error 1

在写Qt时候出现这种错误：解决方法   在.pro中加入  

QT += core gui
QT += widgets

QT +=XXX