python - QTableWidget像excel一样显示某些小数

Question

我的问题是关于 QTableWidget 显示单元格值的方式。

我希望单元格在未被编辑时仅显示三位小数，而当您双击进行编辑时显示完整值。

---

我在后台进行计算，然后设置单元格值。

V_D = 3/0.7
self.TableWidget.setItem(0, 0, QTableWidgetItem(str(V_D)))

类似于 excel 格式化单元格以显示特定位数的方式。

完整值:

显示值:

我该怎么做呢？

Answer 1

解决方案是使用委托(delegate)并覆盖负责显示正常状态下外观的 paint 方法，我基于上述构建了以下类。

class FloatDelegate(QItemDelegate):
    def __init__(self, decimals, parent=None):
        QItemDelegate.__init__(self, parent=parent)
        self.nDecimals = decimals

    def paint(self, painter, option, index):
        value = index.model().data(index, Qt.EditRole)
        try:
            number = float(value)
            painter.drawText(option.rect, Qt.AlignLeft, "{:.{}f}".format(number, self.nDecimals))
        except :
            QItemDelegate.paint(self, painter, option, index)

在您的情况下，您应该按如下方式使用它:

self.TableWidget.setItemDelegate(FloatDelegate(3))

例子:

if __name__ == '__main__':
    import sys
    app = QApplication(sys.argv)
    w = QTableWidget()
    w.setColumnCount(8)
    w.setRowCount(8)
    for i in range(w.rowCount()):
        for j in range(w.columnCount()):
            number = (i+1)/(j+1)
            w.setItem(i, j, QTableWidgetItem(str(number)))
    w.setItemDelegate(FloatDelegate(3, w))
    w.show()
    sys.exit(app.exec_())

截图:

加上:

按行或列:

#only column 2
setItemDelegateForColumn(2, FloatDelegate(3))
#only row 2
setItemDelegateForRow(2, FloatDelegate(3))

如果你只想应用到单元格 2,3

def paint(self, painter, option, index):
   if index.row() == 2 and index.column() == 3:
        value = index.model().data(index, Qt.EditRole)
        try:
            number = float(value)
            painter.drawText(option.rect, Qt.AlignLeft, "{:.{}f}".format(number, self.nDecimals))
        except :
            QItemDelegate.paint(self, painter, option, index)
    else:
        QItemDelegate.paint(self, painter, option, index)

更新:

• QStyledItemDelegate:

  from math import log10
  
  class FloatDelegate(QStyledItemDelegate):
      def __init__(self, decimals, parent=None):
          super(FloatDelegate, self).__init__(parent=parent)
          self.nDecimals = decimals
  
      def displayText(self, value, locale):
          try:
              number = float(value)
          except ValueError:
              return super(FloatDelegate, self).displayText(value, locale)
          else:
              precision = log10(number) + 1 + self.nDecimals
              return locale.toString(number, f='f', prec=precision)