The functionality of Recorder class in Kivy framework is still under development, and is still at experimental stage. The Recorder object records the input events such as touch events, key events and click events. They are recorded in a file with a “.kvi” extension. Kivy uses this file and replays the events by generating equivalent fake events and dispatches them to the event loop.

The Recorder class is defined in the “kivy.input.recorder” module −

from kivy.input.recorder import Recorder
rec = Recorder(**kwargs)

To start recording, press F8 after the Recorder object is instantiated. The event data is recorded in the “recorder.kvi” file in the current folder. You can specify any other filename to the file attribute.

rec = Recorder(filename=''myrecorder.kvi'')

Press F7 to replay the events.

To control the recording and replay manually, use the record and play properties of the Recorder object.

To start recording −

rec = Recorder(filename=''myrecorder.kvi'')
rec.record = True
rec.start()

To stop recording −

rec.record = False
rec.stop()

Similarly, to start replay −

rec.play = True
rec.start()

and, to stop playback −

rec.play = False
rec.stop()

You can make the replay go on in a loop −

def playloop(instance, value):
   if value is False:
      instance.play = True
      
rec = Recorder(filename=''myrecorder.kvi'')
rec.bind(play=playloop)
rec.play = True

Example

In the code given below, a Label is added to a Scatter widget, so that you can perform rotation, zooming and transformation. Further, the text property of the label updates as the user changes the contents of the TextInput box.

The recording and replay of events is defined on the on_press event of two buttons.

Here”s the complete code −

from kivy.app import App
from kivy.uix.label import Label
from kivy.uix.scatter import Scatter
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.textinput import TextInput
from kivy.uix.togglebutton import ToggleButton
from kivy.input.recorder import Recorder
from kivy.core.window import Window

Window.size = (720,400)

class scatterdemoapp(App):
   def build(self):
      self.rec = Recorder(filename=''myrecorder.kvi'')

      box=BoxLayout(orientation=''vertical'')
      box1=BoxLayout(orientation=''horizontal'')
      text1=TextInput(text=''Hi'', pos_hint={''top'':1},height=100, size_hint=(.5, None))
      b1=ToggleButton(text=''record'',pos_hint={''top'':1}, height=100, size_hint=(.25, None))
      b1.bind(on_press=self.on_recording)
      b2=ToggleButton(text=''play'', pos_hint={''top'':1},height=100, size_hint=(.25, None))
      b2.bind(on_press=self.on_playing)
      box1.add_widget(text1)
      box1.add_widget(b1)
      box1.add_widget(b2)
      box.add_widget(box1)
      scatr=Scatter()
      self.lbl=Label(text="Hi", font_size=60, pos=(Window.width/2-100,200 ))
      
      text1.bind(text=self.lbl.setter(''text''))
      scatr.add_widget(self.lbl)
      box.add_widget(scatr)

      return box

   def on_recording(self, obj):
      if obj.state==''down'':
         self.rec.record=True
         self.rec.start()
      else:
         self.rec.record=False
         self.rec.stop()
   def on_playing(self, obj):
      if obj.state==''down'':
         self.rec.play=True
         self.rec.start()
      else:
         self.rec.play=False
         self.rec.stop()
         
scatterdemoapp().run()

Output

The App window appears as shown here −

Hit the record button and all the screen activities including the key_down events are recorded in the “.kvi” file. The console window shows that inputs have been recorded.

[INFO ] [Recorder ] Recording inputs to ''myrecorder.kvi''
[INFO ] [Recorder ] Recorded 901 events in ''myrecorder.kvi''

On pressing the play button to replay the recorded events. Accordingly the console echoes the corresponding log.

[INFO ] [Recorder ] Start playing 901 events from ''myrecorder.kvi''