如何在 Flutter 的 Dismissible 小部件中禁用向左或向右滑动？

Question

I want to disable swiping to the right once there are no data in DataBase.

if (data.length > 1) {
  // I can swipe to the left or right
} else {
  // I can't swipe to the right only left
}                          

Is it real to achieve this? Perhaps, I can return an element to the center once one swiped it to the right

Solution : I just used confirmDismiss in Dismissible widget.

confirmDismiss: (direction) {
  if(data.length > 0 && direction==..)
  // do stuff
  else if(...)
}

Answer 1

Although Sergio's solution works when you have a simple scenario, in my case I had a complex tree below the Dismissible widget (which needed to accept other types of interactions).

Peeking @ flutter's source for Dismissible , I noticed we can set the property direction to DismissDirection.none to prevent swipes. eg:

Dismissible(
   key: UniqueKey(),
   direction: !_canSwipe ? DismissDirection.none : DismissDirection.horizontal,
   (...)

Hope it helps!

Answer 2

一个迟到的答案，但您可以将 Dismissible 的direction属性设置为方向： Dismissible direction: DismissDirection.endToStart,或direction: DismissDirection.startToEnd,

Answer 3

You can use direction property

Set it to DismissDirection.endToStart or DismissDirection.startToEnd

Dismissible(
    direction: DismissDirection.endToStart,
    )

Answer 4

Wrap the dismissible widget with AbsorbPointer . Then, whenever you don't want item to be dismissed, set absorbing to true. Check this for more info link

Answer 5

In case anyone wants to disable dismiss swiping altogether (left or right) you can use DismissDirection.none

*Note this parameter is currently only available on the beta channel

Dismissible(
  direction: data.length > 1 ? DismissDirection.endToStart : DismissDirection.none,
)

Answer 6

Following tomblue's idea I came up with another idea which not only comes free of any error (both compilation and runtime) but also allows the developer to prevent swipe to the right or to the left:

I used the ternary with the properties in dismissThresholds set to impossible values. Full example below:

class SwiperState extends State<Swiper> {
    bool _isNotFirstIndex = false;
    bool _isNotLastIndex = true;
    int _currentIndex = 0;

    void nextOne() {
        setState(() {
            _isNotFirstIndex = !(_currentIndex - 1 < 0);
            _isNotLastIndex = !(_currentIndex + 1 == count);
        });
    }

@override
  Widget build(BuildContext context) {
    return Dismissible(
        dismissThresholds:  {DismissDirection.startToEnd: _isNotFirstIndex ? 0.05 : 2.00, 
            DismissDirection.endToStart: _isNotLastIndex ? 0.05 : 2.00},
        key: UniqueKey(),
        onDismissed: (DismissDirection direction) {
          if(direction == DismissDirection.endToStart) {
            // dismissed to the left, next one
            nextOne();
          }
          else (do the same with prevOne())
               (...)

Answer 7

These links might be helpful:

disable swiping tabs in TabBar flutter

https://inducesmile.com/google-flutter/how-to-disable-swiping-tabs-in-flutter-tabbar/

Answer 8

This is a newly proposed api change, and until then unfortunately we have to reuse the code.

return isDisabled ?
      CardWidgetAndCode(
        ...
      )
    : Dismissible(
      child: CardWidgetAndCode( //  <-- duplicate code and/or function call
        ...
      )
    )