sz_core 2.1.2

SZ Core is a lightweight Flutter utility package that simplifies application development in one package.

SZ Core

A lightweight Flutter package that provides reusable widgets, responsive sizing, utility methods, dialogs, navigation helpers, and a simple API caller to speed up Flutter application development.

Features

• ✅ Responsive UI scaling (.w, .h, .r, .sp)
• ✅ Base Activity & Fragment architecture
• ✅ Built-in API caller (GET,POST,PUT,PATCH & DELETE)
• ✅ Toasts, dialogs & pickers
• ✅ Navigation helper
• ✅ Phone, Website & WhatsApp launcher
• ✅ Keyboard helper
• ✅ Date & Time formatting
• ✅ Random Dark Color generator
• ✅ Hex Color extension
• ✅ Native Android & iOS device information
• ✅ Application information
• ✅ Dynamic User-Agent generation

---

Included Classes

• SZCore
• SZActivity
• SZFragment
• SZApiCaller
• SZApiSetting
• SZShow
• SZText
• SZButton
• SZIconButton
• SZTextField

---

Installation

Add the package to your pubspec.yaml.

dependencies:
  sz_core: ^2.1.2

Then run

flutter pub get

---

Import

import 'package:sz_core/sz_core.dart';

---

Initialization

Initialize SZCore before runApp().

void main() async {
  WidgetsFlutterBinding.ensureInitialized();

  await SZCore.init();

  runApp(const MyApp());
}

With Base URL

void main() async {
  WidgetsFlutterBinding.ensureInitialized();

  await SZCore.init(
    baseURL: "https://example.com/api/",
  );

  runApp(const MyApp());
}

Custom API Settings

void main() async {
  WidgetsFlutterBinding.ensureInitialized();

  SZApiSetting.init(
    "https://example.com/api/",
    keyStatus: "status",
    keyMessage: "message",
    keyData: "data",
    keyInternet: "internet", 
    defaultHeader: {
      "Authorization": "Bearer TOKEN"
    }
  );

  await SZCore.init();

  runApp(const MyApp());
}

You can update custom setting directly from anywhere like

SZApiSetting.defaultHeader = {
   "Authorization": "Bearer UPDATED TOKEN"
};

---

Device Information

SZCore provides native device and application information through Android and iOS platform channels.

The DeviceInfo model contains application, operating system, device, and hardware information.

Get Device Information

final deviceInfo = await SZCore.getDeviceInfo();

Example:

final deviceInfo = await SZCore.getDeviceInfo();

print(deviceInfo.appName);
print(deviceInfo.appVersion);
print(deviceInfo.appBuild);

print(deviceInfo.platform);
print(deviceInfo.osName);
print(deviceInfo.osVersion);

print(deviceInfo.model);
print(deviceInfo.manufacturer);
print(deviceInfo.brand);

print(deviceInfo.identifier);//Android Device Id / IOS ID

DeviceInfo Properties

Property	Description
platform	Platform name, e.g. Android or iOS
appName	Application display name
appVersion	Application version
appBuild	Application build number
model	Device model
manufacturer	Device manufacturer
brand	Device brand
device	Android device code name
product	Android product name
osName	Operating system name
osVersion	Operating system version
sdk	Android SDK/API level
abis	Supported CPU architectures
deviceName	User-visible device name
identifier	Platform-provided identifier

Example Output

Android:

Platform      : Android
App Name      : My App
App Version   : 1.2.0
App Build     : 25
Manufacturer  : Samsung
Brand         : Samsung
Model         : SM-S928B
OS Name       : Android
OS Version    : 15
SDK           : 35
ABIs          : arm64-v8a
identifier    : b3e32457fd3ec2a4

iOS:

Platform      : iOS
App Name      : My App
App Version   : 1.2.0
App Build     : 25
Model         : iPhone
OS Name       : iOS
OS Version    : 18.6
identifier    : 11112222222332

---

User-Agent

SZCore can generate a dynamic User-Agent using the application and device information.

final headers = await SZCore.getDefaultHeader();

Example Android:

My App/1.2.0 (Android 15; Samsung SM-S928B; Build 25)

Example iOS:

My App/1.2.0 (iOS 18.6; iPhone; Build 25)

You can use the generated header with your API requests:

final headers = await SZCore.getDefaultHeader();

print(headers["User-Agent"]);

Responsive Size

SZCore.init() automatically calculates the screen scale.

Use the extensions anywhere.

Container(
  width: 120.w,
  height: 60.h,
  padding: EdgeInsets.all(12.r),
  child: SZText(
    "Hello",
    fontSize: 16.sp,
  ),
)

Extension	Description
.w	Width scaling
.h	Height scaling
.r	Radius scaling
.sp	Responsive font size

---

SZActivity

Replace State with SZActivity.

Replace build() with buildContent().

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

  @override
  State<HomeActivity> createState() => _HomeActivityState();
}

class _HomeActivityState extends SZActivity<HomeActivity> {

  @override
  Widget buildContent(BuildContext context) {
    return const SizedBox();
  }
}

Available Methods

showDialog("Loading...");

hideDialog();

open(const SecondActivity());

onResume();

onPaused();

---

SZFragment

Replace State with SZFragment.

Replace build() with buildContent().

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

  @override
  State<HomeFragment> createState() => _HomeFragmentState();
}

class _HomeFragmentState extends SZFragment<HomeFragment> {

  @override
  Widget buildContent(BuildContext context) {
    return const SizedBox();
  }
}

Available Methods

showDialog("Loading...");

hideDialog();

open(const SecondActivity());

onResume();

onPaused();

---

SZCore

Open Activity

Open a new activity:

await SZCore.open(
  context,
  const HomeActivity(),
);

Parameters

Parameter	Default	Description
finish	false	Closes the current activity before opening the new activity.
onlyOne	false	Clears all previous activities and opens the new activity as the only active activity.

Example

await SZCore.open(
  context,
  const HomeActivity(),
  finish: true,
  onlyOne: true,
);

---

Hide Keyboard

SZCore.hideKeyboard(context);

---

Screen Size

final size = await SZCore.getScreenSize();

 SZCore.printLog(size.width);
 SZCore.printLog(size.height);

---

Date Formatting

Server format

SZCore.formattedDate(DateTime.now());

Output

2026-07-07

Display format

SZCore.formattedDate(
  DateTime.now(),
  server: false,
);

Output

7 Jul 2026

---

Time Formatting

Server

SZCore.formattedTime(DateTime.now());

Output

14:30

Display

SZCore.formattedTime(
  DateTime.now(),
  server: false,
);

Output

2:30 PM

---

Random Dark Color

Color color = SZCore.getRandomDarkColor();

---

Debug Log

SZCore.printLog("Hello");

Prints only in Debug mode.

---

Open Phone Dialer

SZCore.openCall("9876543210");

---

Open Website

SZCore.openWebsite(
  "https://flutter.dev",
);

---

Open WhatsApp

SZCore.openWhatsApp(
  "919876543210",
  message: "Hello",
);

---

Hex Color Extension

Color color = "#2196F3".toColor();

---

SZShow

Toast

SZShow.toast("Saved Successfully");

Custom

SZShow.toast(
  "Error",
  bg: Colors.red,
  color: Colors.white,
  size: 14,
);

---

Dialog

SZShow.dialog(
  context,
  "Success",
  "Data Saved Successfully",
);

Two Buttons

SZShow.dialog(
  context,
  "Delete",
  "Delete this record?",
  btn1: "Yes",
  btn2: "No",
  b1Click: () {

  },
  b2Click: () {

  },
);

Custom Widget

SZShow.dialog(
  context,
  "",
  "",
  buildContent: (setState) {
    return const Text("Custom Widget");
  },
);

---

Date Picker

SPair date = await SZShow.dateSelect(
  context,
  null,
);

---

Time Picker

SPair time = await SZShow.timeSelect(
  context,
  null,
);

---

Year Picker

int year = await SZShow.yearSelect(
  context,
  2025,
);

---

Widgets

SZText

A customizable text widget with support for icons, required indicators, shadows, and responsive font sizing.

const SZText(
  'Welcome to SZ Core',
  fontSize: 16,
  fontWeight: FontWeight.bold,
);

const SZText(
  'Email Address',
  required: true,
  icon: Icons.email,
);

---

SZButton

A customizable button with support for icons, colors, borders, and disabled states.

SZButton(
  text: 'Login',
  onClick: () {
    login();
  },
);

SZButton(
  text: 'Delete',
  icon: Icons.delete,
  btnColor: Colors.red,
  onClick: deleteItem,
);

---

SZIconButton

A compact icon button with support for custom widgets and long-click actions.

SZIconButton(
  icon: Icons.edit,
  onClick: () {
    editProfile();
  },
);

SZIconButton(
  icon: Icons.delete,
  bgColor: Colors.red,
  onClick: deleteItem,
  onLongClick: showDeleteConfirmation,
);

---

SZTextField

A customizable text field with support for icons, labels, password mode, and keyboard configuration.

SZTextField(
  hint: 'Enter your name',
  controller: nameController,
);

SZTextField(
  hint: 'Password',
  obscureText: true,
  suffixIcon: Icons.visibility,
);

---

SZDropDown

A generic dropdown widget supporting any object type.

SZDropDown<Pair>(
  true,
  selectedCountry,
  countries,
  (value) {
    setState(() {
      selectedCountry = value;
    });
  },
  toStringConvert: (item) => item.name,
);

---

SZAutoComplete

An autocomplete widget with asynchronous search support.

SZAutoComplete<Pair>(
  isEnable: true,
  value: selectedUser,
  onSearch: (keyword) async {
    return await searchUsers(keyword);
  },
  displayText: (item) => item.name,
  onSelected: (item) {
    selectedUser = item;
  },
);

---

SZApiCaller

Supports both GET and POST requests.

GET Request

SZApiCaller(
  context,
  this,
  1,
  null,
  "Loading...",
  "users",
).then((response, key) {

});

---

POST Request

SZApiCaller(
  context,
  this,
  2,
  jsonEncode(data),
  "Please wait...",
  "login",
).then((response, key) {

});

PUT,PATCH,DELETE Request

You can use below enum

enum SZMethod { get, post, delete, put, patch }

SZApiCaller(
  context,
  this,
  2,
  jsonEncode(data),
  "Please wait...",
  "login",
  method = SZMethod.put
).then((response, key) {

});

---

Custom Header

SZApiCaller(
  context,
  this,
  1,
  null,
  null,
  "users",
  customHeader: {
    "Authorization": "Bearer TOKEN"
  },
).then((response, key) {

});

---

Logout Callback

SZCore.logoutCallback = () {
  // Navigate to Login Screen
};

If the API response contains "session expire", the callback is automatically invoked.

---

Requirements

• Flutter SDK >= 3.0.0

---

Contributing

Contributions, issues, and feature requests are welcome.

---

License

This project is licensed under the MIT License. See the LICENSE file for details.