Fix bug Field 'lastPosition' has not been initialized when pressed

[nguyenxdat]

When the user pressed (not drag item) this error occurs

════════ Exception caught by gesture ═══════════════════════════════════════════
The following LateError was thrown while handling a gesture:
LateInitializationError: Field 'lastPosition' has not been initialized.

When the exception was thrown, this was the stack
#0      _SlidableGestureDetectorState.lastPosition (package:flutter_slidable/src/gesture_detector.dart)
package:flutter_slidable/src/gesture_detector.dart:1
#1      _SlidableGestureDetectorState.handleDragEnd
package:flutter_slidable/src/gesture_detector.dart:93
#2      DragGestureRecognizer._checkEnd.<anonymous closure>
package:flutter/…/gestures/monodrag.dart:473
#3      GestureRecognizer.invokeCallback
package:flutter/…/gestures/recognizer.dart:182
#4      DragGestureRecognizer._checkEnd
package:flutter/…/gestures/monodrag.dart:473
...
Handler: "onEnd"
Recognizer: HorizontalDragGestureRecognizer#c5a3b
    debugOwner: GestureDetector
    start behavior: down
════════════════════════════════════════════════════════════════════════════════
Application finished.

[letsar]

I cannot reproduce, on which Flutter branch are you?

[nguyenxdat]

I used to flutter_slidable 1.0.0-dev.8 version at
video demo
code demo
@letsar

[letsar]

Oh thanks, I've been able to fix it by another way in the 1.0.0-dev.9. I'm closing this it's published. Thank you again for the repro case 👍