zoom_view 0.0.17

Widget that allows both zooming and scrolling a ListView or other Scrollables

Widget that allows both zooming and scrolling a ListView, or other Scrollables

Usage

Using ListView

import 'package:flutter/material.dart';
import 'package:zoom_view/zoom_view.dart';

void main() {
  runApp(const MaterialApp(home: MyApp()));
}

class MyApp extends StatefulWidget {
  const MyApp({super.key});
  @override
  State<MyApp> createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  ScrollController controller = ScrollController();
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: ZoomListView(
        child: ListView.builder(
            controller: controller,
            itemCount: 10000,
            itemBuilder: (context, index) {
              return Center(
                  child: Text("text $index")
              );
            }
        ),
      ),
    );
  }
}

Note that the controller argument most be set for your ListView.

Using some other scrolling list

class ZoomViewExample extends StatefulWidget {
  const ZoomViewExample({super.key});

  @override
  State<ZoomViewExample> createState() => _ZoomViewExampleState();
}

class _ZoomViewExampleState extends State<ZoomViewExample> {
  ScrollController controller = ScrollController();
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: ZoomView(
        controller: controller,
        child: ListView.builder(
            controller: controller,
            itemCount: 10000,
            itemBuilder: (context, index) {
              return Center(
                  child: Text("text $index")
              );
            }
        ),
      ),
    );
  }
}

Note that here the controller is given both to the ZoomView and the List.

Double-tap to zoom

class ZoomViewExample extends StatefulWidget {
  const ZoomViewExample({super.key});

  @override
  State<ZoomViewExample> createState() => _ZoomViewExampleState();
}

class _ZoomViewExampleState extends State<ZoomViewExample> {
  ScrollController controller = ScrollController();
  ZoomViewGestureHandler handler = ZoomViewGestureHandler(zoomLevels: [2,1]);

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: ZoomView(
        controller: controller,
        onDoubleTapDown: (ZoomViewDetails zoomViewDetails){
           handler.onDoubleTap(zoomViewDetails);
        },
        child: ListView.builder(
            controller: controller,
            itemCount: 10000,
            itemBuilder: (context, index) {
              return Center(
                  child: Text("text $index")
              );
            }
        ),
      ),
    );
  }
}

Using ScrollablePositionedList

You will need to use this fork of scrollable_positioned_list which exposes the list's ScrollPosition in ScrollOffsetController:

  scrollable_positioned_list:
    git: https://github.com/yakagami/scrollable_positioned_list

Alternatively, you can add expose the ScrollPosition in ScrollOffsetController yourself, found in scrollable_positioned_list/lib/src/scrollable_positioned_list.dart

  ScrollPosition get position => _scrollableListState!.primary.scrollController.position;

Then add this class to your project:

class ScrollOffsetToScrollController extends ScrollController{
  ScrollOffsetToScrollController({required this.scrollOffsetController});
  final ScrollOffsetController scrollOffsetController;

  @override
  ScrollPosition get position => scrollOffsetController.position;

  @override
  void jumpTo(double value){
    scrollOffsetController.jumpTo(value);
  }

  @override
  Future<void> animateTo(double offset, {required Curve curve, required Duration duration}){
    return scrollOffsetController.animateScroll(offset: offset, duration: duration);
  }
}

Usage:

final ScrollOffsetController scrollOffsetController = ScrollOffsetController();

ZoomView(
  controller: ScrollOffsetToScrollController(
    scrollOffsetController: scrollOffsetController,
  ),
  child: ScrollablePositionedList.builder(
    scrollOffsetController : scrollOffsetController,
    itemBuilder: (context, index) => Text('Item $index'),
  ),
),