Pinch to zoom listview in flutter

user_17853431 0
Viewed 569

So I am trynna make a widget with pinch to zoom in listview, list view contains: container that contains text. So you can basically pinch in to zoom the whole listview. I have looked into flutter interactive viewer and zoom library but it doesn't seem to be working.

From the following:

From This

To the following:

To this

Any thoughts n prayers.

flutter-animation flutter-dependencies flutter-test flutter-layout flutter
3 Answers

You Can pass any widget to this class and can zoom the widget as you can!!

import 'package:flutter/material.dart';
import 'package:flutter/widgets.dart';
import 'package:vector_math/vector_math_64.dart';

class ZoomableWidget extends StatefulWidget {
  final Widget child;

   const ZoomableWidget({Key? key, required this.child}) : super(key: key);
  @override
  _ZoomableWidgetState createState() => _ZoomableWidgetState();
}

class _ZoomableWidgetState extends State<ZoomableWidget> {
  double _scale = 1.0;
  late double _previousScale;
  @override
  Widget build(BuildContext context) {
    return ClipRect(
      child: GestureDetector(
        onScaleStart: (ScaleStartDetails details) {
          _previousScale = _scale;
        },
        onScaleUpdate: (ScaleUpdateDetails details) {
          setState(() {
            _scale = _previousScale * details.scale;
          });
        },
        onScaleEnd: (ScaleEndDetails details) {
          _previousScale = 0;
        },
        child: Transform(
          transform: Matrix4.diagonal3(Vector3(_scale.clamp(1.0, 5.0),
              _scale.clamp(1.0, 5.0), _scale.clamp(1.0, 5.0))),
          alignment: FractionalOffset.center,
          child: widget.child, **add your listview here**
        ),
      ),
    );
  }
}
user_130492880

For this I have 2 solutions, hope it will work for you too.

  1. InteractiveViewer

InteractiveViewer widget supports pan and Zoom out of the box.

To make any widget zoomable you need to simply wrap the child with InteractiveViewer.

@override
Widget build(BuildContext context) {
  return Center(
    child: InteractiveViewer(
      panEnabled: false, // Set it to false to prevent panning. 
      boundaryMargin: EdgeInsets.all(80),
      minScale: 0.5,
      maxScale: 4, 
      child: FlutterLogo(size: 200),
    ),
  );
}
  1. matrix_gesture_detector

A gesture detector package created by @pskink to handle the rotation, scale, and zoom.

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

class ZoomableWidget extends StatefulWidget {
  final Widget child;

  const ZoomableWidget({Key key, this.child}) : super(key: key);
  @override
  _ZoomableWidgetState createState() => _ZoomableWidgetState();
}

class _ZoomableWidgetState extends State<ZoomableWidget> {
  Matrix4 matrix = Matrix4.identity();

  @override
  Widget build(BuildContext context) {
    return MatrixGestureDetector(
      onMatrixUpdate: (Matrix4 m, Matrix4 tm, Matrix4 sm, Matrix4 rm) {
        setState(() {
          matrix = m;
        });
      },
      child: Transform(
        transform: matrix,
        child: widget.child,
      ),
    );
  }
}
user_96714450

So instead what I ended up doing was setting on-pinch to zoom or zoom-out increase/decrease the size of the text. And it worked like a charm.

user_178534310
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