Source Code for Module pyjamas.ui.DragHandler

 1  # Copyright (C) 2010 Jim Washington 
 2  # 
 3  # Licensed under the Apache License, Version 2.0 (the "License"); 
 4  # you may not use this file except in compliance with the License. 
 5  # You may obtain a copy of the License at 
 6  # 
 7  #     http://www.apache.org/licenses/LICENSE-2.0 
 8  # 
 9  # Unless required by applicable law or agreed to in writing, software 
10  # distributed under the License is distributed on an "AS IS" BASIS, 
11  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
12  # See the License for the specific language governing permissions and 
13  # limitations under the License. 
14   
15  from pyjamas import DOM 
16  from pyjamas.ui import Event 
17   
18  DRAG_EVENTS = [ "dragstart", "drag", "dragend"] 
19   
20 -def fireDragEvent(listeners, event): 
21      etype = DOM.eventGetType(event) 
22      if etype == "dragstart": 
23          for listener in listeners: 
24              listener.onDragStart(event) 
25          return True 
26      elif etype == "drag": 
27          for listener in listeners: 
28              listener.onDrag(event) 
29          return True 
30      elif etype == "dragend": 
31          for listener in listeners: 
32              listener.onDragEnd(event) 
33          return True 
34      return False 
35   
36 -class DragHandler(object): 
37   
38 -    def __init__(self): 
39          self._dragListeners = [] 
40          self.sinkEvents(Event.DRAGEVENTS) 
41   
42 -    def onBrowserEvent(self, event): 
43          event_type = DOM.eventGetType(event) 
44          if event_type in DRAG_EVENTS: 
45              return fireDragEvent(self._dragListeners, event) 
46          return False 
47   
48 -    def addDragListener(self, listener): 
49          self._dragListeners.append(listener) 
50   
51 -    def removeDragListener(self, listener): 
52          self._dragListeners.remove(listener) 
53   
54 -    def onDragStart(self, event): 
55          """ 
56          Store data into the DataTransfer object and set the allowed effects. 
57   
58          Set data into the event's dataTransfer with a content-type and some 
59          string data. 
60   
61          Some native dataTransfer objects will only set content-type of "Text" 
62          and/or "URL". 
63   
64          allowedEffects is one of: 'none', 'copy', 'copyLink', 'copyMove', 
65          'link', 'linkMove', 'move', or 'all' 
66   
67          an example:: 
68   
69           dt = event.dataTransfer 
70           dt.setData('text/plain','Hello, World!') 
71           dt.allowedEffects = 'copyMove' 
72          """ 
73          pass 
74   
75 -    def onDrag(self, event): 
76          """ 
77          this happens periodically while the drag is in progress. 
78          use DOM.eventPreventDefault(event) to cancel drag operation 
79          """ 
80          pass 
81   
82 -    def onDragEnd(self, event): 
83          """ 
84          This happens on the initiating widget after the dragging mouse 
85          is released. 
86          """ 
87          pass 
88