Tuesday, March 19, 2024

Opensource grid view control for Flutter

The json_table widget is a Flutter package that allows you to create tables from JSON data. With this package, you can display complex JSON data in an easy-to-read tabular format.

The json_table package provides a customizable table view that supports searching, filtering, sorting, and pagination.

You need to provide it with a JSON array of data and a list of columns that you want to display in the table. The columns can be customized with labels, text styles, and column widths. The package also provides a number of additional features, such as support for custom cell builders and column toggling.

Features

  • The table constructed isn’t the flutter’s native DataTable.
  • The table is manually coded hence serves a great learning purpose on how to create simple tables manually in flutter
  • Supports vertical & horizontal scroll
  • Supports custom columns includes default value, column name, value builder
  • Supports nested data showing
  • Supports pagination
  • Supports row select color, callback

Installation

In the dependencies: section of your pubspec.yaml, add the following line:

dependencies:
  json_table: <latest version>

Usage

Import this class

import 'package:json_table/json_table.dart';

Vanilla Implementation

//Decode your json string
final String jsonSample='[{"id":1},{"id":2}]';
var json = jsonDecode(jsonSample);

//Simply pass this json to JsonTable
child: JsonTable(json)

Implementation with HEADER and CELL widget builders

JsonTable(
   json,
   tableHeaderBuilder: (String header) {
     return Container(
       padding: EdgeInsets.symmetric(horizontal: 8.0, vertical: 4.0),
       decoration: BoxDecoration(border: Border.all(width: 0.5),color: Colors.grey[300]),
       child: Text(
         header,
         textAlign: TextAlign.center,
         style: Theme.of(context).textTheme.display1.copyWith(fontWeight: FontWeight.w700, fontSize: 14.0,color: Colors.black87),
       ),
     );
   },
   tableCellBuilder: (value) {
     return Container(
       padding: EdgeInsets.symmetric(horizontal: 4.0, vertical: 2.0),
       decoration: BoxDecoration(border: Border.all(width: 0.5, color: Colors.grey.withOpacity(0.5))),
       child: Text(
         value,
         textAlign: TextAlign.center,
         style: Theme.of(context).textTheme.display1.copyWith(fontSize: 14.0, color: Colors.grey[900]),
       ),
     );
   },
 )

Implementation with custom COLUMNS list

  • Pass custom column list to control what columns are displayed in table
  • The list item must be constructed using JsonTableColumn class
  • JsonTableColumn provides 4 parameters, namely,
JsonTableColumn("age", label: "Eligible to Vote", valueBuilder: eligibleToVote, defaultValue:"NA")
  • First parameter is the field/key to pick from the data
  • label: The column header label to be displayed
  • defaultValue: To be used when data or key is null
  • valueBuilder: To get the formatted value like date etc
//Decode your json string
final String jsonSample='[{"name":"Ram","email":"ram@gmail.com","age":23,"DOB":"1990-12-01"},'
                              '{"name":"Shyam","email":"shyam23@gmail.com","age":18,"DOB":"1995-07-01"},'
                              '{"name":"John","email":"john@gmail.com","age":10,"DOB":"2000-02-24"},'
                              '{"name":"Ram","age":12,"DOB":"2000-02-01"}]';
var json = jsonDecode(jsonSample);
//Create your column list
var columns = [
      JsonTableColumn("name", label: "Name"),
      JsonTableColumn("age", label: "Age"),
      JsonTableColumn("DOB", label: "Date of Birth", valueBuilder: formatDOB),
      JsonTableColumn("age", label: "Eligible to Vote", valueBuilder: eligibleToVote),
      JsonTableColumn("email", label: "E-mail", defaultValue: "NA"),
    ];
//Simply pass this column list to JsonTable
child: JsonTable(json,columns: columns)

//Example of valueBuilder
String eligibleToVote(value) {
    if (value >= 18) {
      return "Yes";
    } else
      return "No";
}

Demo