Python Tkinter：树双击节点

Question

我在 Canvas 中用 idlelib.TreeWidget 创建了 2 棵树，左侧和右侧。

如果双击，我可以打印出树节点的名称，但我需要的是仅从左侧双击树节点会打印出消息。

请运行以下代码（左树为self.canvas，右为self.canvas2）：

from Tkinter import Tk, Frame, BOTH, Canvas
from xml.dom.minidom import parseString
from idlelib.TreeWidget import TreeItem, TreeNode

class DomTreeItem(TreeItem):
   def __init__(self, node):
      self.node = node
   def GetText(self):
      node = self.node
      if node.nodeType == node.ELEMENT_NODE:
         return node.nodeName
      elif node.nodeType == node.TEXT_NODE:
         return node.nodeValue
   def IsExpandable(self):
      node = self.node
      return node.hasChildNodes()
   def GetSubList(self):
      parent = self.node
      children = parent.childNodes
      prelist = [DomTreeItem(node) for node in children]
      itemlist = [item for item in prelist if item.GetText().strip()]
      return itemlist
   def OnDoubleClick(self):
      print self.node.nodeName

content = '''
<level0>
 <level1/>
</level0>
'''
class Application(Frame):

   def __init__(self, parent):
      Frame.__init__(self, parent)
      self.parent = parent
      self.parent.geometry('%dx%d+%d+%d' % (800, 300, 0, 0))
      self.parent.resizable(0, 0)

      dom = parseString(content)
      item = DomTreeItem(dom.documentElement)
      self.canvas = Canvas(self, bg = "cyan")
      self.canvas.grid(column = 0, row = 0, sticky = 'NSWE')
      node = TreeNode(self.canvas, None, item)
      node.update()

      dom2 = parseString(content)
      item2 = DomTreeItem(dom2.documentElement)
      self.canvas2 = Canvas(self, bg = "yellow")
      self.canvas2.grid(column = 1, row = 0, sticky = 'NSWE')
      node2 = TreeNode(self.canvas2, None, item2)
      node2.update()

      self.pack(fill = BOTH, expand = True)

def main():
   root = Tk()
   Application(root)
   root.mainloop()

if __name__ == '__main__':
   main()  

Answer 1

您只需要修改DomTreeItem 类以采用一个参数来确定它是否应该对双击起作用：

class DomTreeItem(TreeItem):
   def __init__(self, node, doubleclick=True): # set the value of double-click
      self.node = node
      self.doubleclick = doubleclick           # make the value an instance variable
   def GetText(self):
      node = self.node
      if node.nodeType == node.ELEMENT_NODE:
         return node.nodeName
      elif node.nodeType == node.TEXT_NODE:
         return node.nodeValue
   def IsExpandable(self):
      node = self.node
      return node.hasChildNodes()
   def GetSubList(self):
      parent = self.node
      children = parent.childNodes
      prelist = [DomTreeItem(node, self.doubleclick) for node in children] # pass it to the nodes
      itemlist = [item for item in prelist if item.GetText().strip()]
      return itemlist
   def OnDoubleClick(self):
      if self.doubleclick:         # check if it's set to True
         print self.node.nodeName  # and only print it then

然后，当您创建该类的新实例时，只需将doubleclick 设置为True 或False。如果您不想双击触发第二棵树，请像这样实例化它：

item2 = DomTreeItem(dom2.documentElement, doubleclick=False)