dynamic_widget 1.0.2

Pub  Awesome Flutter

Flutter Dynamic Widget #

You can dynamic update your flutter page with Flutter Dynamic Widget. It's a light json UI protocol, which is very similar with flutter widget code. So you don't need to learn another UI protocol, if you are familiar with flutter widget, you might already know how to write Flutter Dynamic Widget json.

Table of contents #

General info #

I work for an e-commerce company. We need to build flexible pages. So we define a light UI protocol, and implement on Android and iOS. We can dynamic update App UIs by pushing a json file. With this ability, we can do some UI A/B testing without publishing App to app store. Flutter allows you to build beautiful native apps on iOS and Android from a single codebase, it can allow you to build web app later. Flutter's hot reload helps you quickly and easily experiment, build UIs, add features, and fix bugs faster. But it still build native app, the UIs can't be dynamic updated. If you want to modify the UIs, you need to publish the updated app to app store. With this project, you can build your UIs from a json string, which is the UI protocal. The json string is very similar with the Flutter widget dart code. All widget type and widget properties are the same.

Widget type will be a type property, and widget's properties will be the json properties too. All properties and their values will be almost the same. You can checkout the following document.

Currently support flutter widgets and properties

Screenshots #

Install #

1. Depend on it #

Add this to your package's pubspec.yaml file:

  dynamic_widget: ^0.0.1

2. Install it #

You can install packages from the command line:

with Flutter:

$ flutter packages get

Alternatively, your editor might support flutter packages get. Check the docs for your editor to learn more.

3. Import it #

Now in your Dart code, you can use:

import 'package:dynamic_widget/dynamic_widget.dart';

Get started #

You should use DynamicWidgetBuilder().build method to covert a json string into flutter widget. It will be time-consuming. so you'd better using FutureBuilder to build the UI.

import 'package:dynamic_widget/dynamic_widget.dart';
class PreviewPage extends StatelessWidget{

  final String jsonString;


  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(
          // Here we take the value from the MyHomePage object that was created by
          // the App.build method, and use it to set our appbar title.
          title: Text("Preview"),
        body: FutureBuilder<Widget>(
          future: _buildWidget(),
          builder: (BuildContext context, AsyncSnapshot<Widget> snapshot){
            return snapshot.hasData?snapshot.data:Text("Loading...");

  Future<Widget> _buildWidget() async{

    return DynamicWidgetBuilder().build(jsonString, null);

How to implement a WidgetParser #

  1. You need to implement the WidgetParser abstract class.
  2. Add new created WidgetParser to DynamicWidgetBuilder.parsers list.

This is a RaisedButton widget parser.

import 'package:dynamic_widget/dynamic_widget/utils.dart';
import 'package:dynamic_widget/dynamic_widget.dart';
import 'package:flutter/material.dart';

class RaisedButtonParser extends WidgetParser{
  bool forWidget(String widgetName) {
    return "RaisedButton" == widgetName;

  Widget parse(Map<String, dynamic> map) {
    return RaisedButton(
      color: map.containsKey('color') ? parseHexColor(map['color']) : null,
      disabledColor: map.containsKey('disabledColor') ? parseHexColor(map['disabledColor']) : null,
      disabledElevation: map.containsKey('disabledElevation') ? map['disabledElevation'] : 0.0,
      disabledTextColor: map.containsKey('disabledTextColor') ? parseHexColor(map['disabledTextColor']) : null,
      elevation: map.containsKey('elevation') ? map['elevation'] : 0.0,
      padding: map.containsKey('padding') ? parseEdgeInsetsGeometry(map['padding']) : null,
      splashColor : map.containsKey('splashColor') ? parseHexColor(map['splashColor']) : null,
      textColor: map.containsKey('textColor') ? parseHexColor(map['textColor']) : null,
      child: DynamicWidgetBuilder().buildFromMap(map['child']),
      onPressed: (){},


Add it to parsers list.

class DynamicWidgetBuilder{

  final Logger log = Logger('DynamicWidget');

  static final parsers = [

  Widget build(String json){

    var map = jsonDecode(json);
    return buildFromMap(map);

  Widget buildFromMap(Map<String, dynamic> map){
    String widgetName = map['type'];

    for (var parser in parsers) {
      if (parser.forWidget(widgetName)) {
        return parser.parse(map);

    log.warning("Not support type: $widgetName");
    return null;

  List<Widget> buildWidgets(List<dynamic> values){
    List<Widget> rt = [];
    for (var value in values) {
    return rt;

How to add a click listener #

Add "click_event" property to your widget json definition. for example:

var raisedButton_json =
  "type": "Container",
  "alignment": "center",
  "child": {
    "type": "RaisedButton",
    "color": "##FF00FF",
    "padding": "8,8,8,8",
    "textColor": "#00FF00",
    "elevation" : 8.0,
    "splashColor" : "#00FF00",
    "click_event" : "route://productDetail?goods_id=123",
    "child" : {
      "type": "Text",
      "data": "I am a button"

We suggest you'd better to use an URI to define the event, as the exmaple, it's a event for going to a product detail page.

Then, define a ClickListener

class DefaultClickListener implements ClickListener{
  void onClicked(String event) {
    print("Receive click event: " + event);


Finally, pass the listener to build method.

  Future<Widget> _buildWidget() async{

    return DynamicWidgetBuilder().build(jsonString, new DefaultClickListener());

Widget Documents #

Already completed widgets:

You can view Currently support widgets and properties here.

Setup #

Checkout this project and run deom.

Code Examples #

Checkout this project and run deom.

Contact #

Created by @deng.yin@gmail.com - feel free to contact me!

[0.0.1] - init release

  • initial release.

[0.0.2] - Add more flutter widgets

  • Add more flutter widgets

[0.0.3] - ListView & GridView add "auto load more" feature.

  • ListView & GridView add "auto load more" feature.

[1.0.2] - Add more widgets support.

  • Add more flutter widgets

[1.0.2] - Add click listener and more widgets support.

  • Add Click listener support
  • Add more flutter widgets


demo #

Dynamic widget demo

Getting Started #

This project is a starting point for a Flutter application.

A few resources to get you started if this is your first Flutter project:

For help getting started with Flutter, view our online documentation, which offers tutorials, samples, guidance on mobile development, and a full API reference.

Use this package as a library

1. Depend on it

Add this to your package's pubspec.yaml file:

  dynamic_widget: ^1.0.2

2. Install it

You can install packages from the command line:

with Flutter:

$ flutter pub get

Alternatively, your editor might support flutter pub get. Check the docs for your editor to learn more.

3. Import it

Now in your Dart code, you can use:

import 'package:dynamic_widget/dynamic_widget.dart';
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Learn more about scoring.

We analyzed this package on Jul 22, 2019, and provided a score, details, and suggestions below. Analysis was completed with status completed using:

  • Dart: 2.4.0
  • pana: 0.12.19
  • Flutter: 1.7.8+hotfix.3


Detected platforms: Flutter

References Flutter, and has no conflicting libraries.

Health suggestions

Fix lib/dynamic_widget/basic/cliprrect_widget_parser.dart. (-0.50 points)

Analysis of lib/dynamic_widget/basic/cliprrect_widget_parser.dart reported 1 hint:

line 3 col 8: Don't import implementation files from another package.

Format lib/dynamic_widget/basic/container_widget_parser.dart.

Run flutter format to format lib/dynamic_widget/basic/container_widget_parser.dart.

Format lib/dynamic_widget/basic/image_widget_parser.dart.

Run flutter format to format lib/dynamic_widget/basic/image_widget_parser.dart.

Format lib/dynamic_widget/utils.dart.

Run flutter format to format lib/dynamic_widget/utils.dart.

Maintenance suggestions

The description is too long. (-10 points)

Search engines display only the first part of the description. Try to keep the value of the description field in your package's pubspec.yaml file between 60 and 180 characters.


Package Constraint Resolved Available
Direct dependencies
Dart SDK >=2.0.0-dev.68.0 <3.0.0
flutter 0.0.0
logging ^0.11.3+2 0.11.3+2
Transitive dependencies
collection 1.14.11
meta 1.1.6 1.1.7
sky_engine 0.0.99
typed_data 1.1.6
vector_math 2.0.8
Dev dependencies