Developer Blog

Tipps und Tricks für Entwickler und IT-Interessierte

Migration

by Ralph Ionic, Ionic 4, Mobile Development

Vorbereitung / Installation

Hier findet ihr die genaue Beschreibung

npm i -D @ionic/v4-migration-tslint
npm i codelyzer

Erstellen einer JSON Datei ionic-migration.json

{
  "rulesDirectory": [
    "@ionic/v4-migration-tslint/rules"
  ],
  "rules": {
    "ion-action-sheet-method-create-parameters-renamed": true,
    "ion-alert-method-create-parameters-renamed": true,
    "ion-datetime-capitalization-changed": true,
    "ion-item-option-method-get-sliding-percent-renamed": true,
    "ion-back-button-not-added-by-default": { "options": [true], "severity": "warning" },
    "ion-button-attributes-renamed": true,
    "ion-button-is-now-an-element": true,
    "ion-chip-markup-has-changed": true,
    "ion-fab-button-is-now-an-element": true,
    "ion-fab-attributes-renamed": true,
    "ion-fab-fixed-content": true,
    "ion-col-attributes-renamed": true,
    "ion-icon-attribute-is-active-removed": true,
    "ion-item-is-now-an-element": true,
    "ion-item-ion-label-required": true,
    "ion-item-attributes-renamed": true,
    "ion-item-divider-ion-label-required": true,
    "ion-item-options-attribute-values-renamed": true,
    "ion-item-option-is-now-an-element": true,
    "ion-label-attributes-renamed": true,
    "ion-list-header-ion-label-required": true,
    "ion-menu-toggle-is-now-an-element": true,
    "ion-navbar-is-now-ion-toolbar": true,
    "ion-option-is-now-ion-select-option": true,
    "ion-radio-attributes-renamed": true,
    "ion-radio-slot-required": true,
    "ion-radio-group-is-now-an-element": true,
    "ion-range-attributes-renamed": true,
    "ion-spinner-attribute-values-renamed": true,
    "ion-tab-attributes-renamed": true,
    "ion-text-is-now-an-element": true,
    "ion-buttons-attributes-renamed": true
  }
}

Migration durchführen

npx tslint -c ionic-migration.json -p tsconfig.json

Flutter | Troubleshooting

by Ralph Flutter

Basic

flutter doctor

Error: Exception: Bad UTF-8 encoding
Solution: Use the current version of vswhere

Download from: https://github.com/microsoft/vswhere/releases

Store/overwrite: C:\Program Files (x86)\Microsoft Visual Studio\Installer\vswhere.exe

PS> Set-Location "C:\Program Files (x86)\Microsoft Visual Studio\Installer"                                                                                                                                              
PS> Move-Item vswhere.exe vswhere.exe.original
PS> Invoke-WebRequest https://github.com/microsoft/vswhere/releases/download/3.0.3/vswhere.exe -O vswhere.exe
Null safety features are disabled for this library.
lib/main.dart:8:19: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.12 or higher.
  const MyApp({Key? key}) : super(key: key);
Solution: Edit pubspec.yaml
environment:
  sdk: '>=2.17.3 <3.0.0'

Migration Dart Plugins

import 'package:flutter/services.dart';
client =createHttpClient();

 

import 'package:http/http.dart' as http;
client = new http.Client();

Your app is not using AndroidX

GoTo Flutter_Project -> android -> gradle.properties file. Open the gradle.properties file in any Text editor.

Add below lines in this file and Save the file.

android.useAndroidX=true
android.enableJetifier=true

Open your Flutter Project Root directory in Command Prompt or Terminal and execute

flutter clean

Flutter | Getting started

by Ralph Flutter, Mobile Development

Installation

Installation of Flutter

Details are here

Installation of Dart SDK

Details are here

$ brew tap dart-lang/dart
$ brew install dart --devel

Create your first App

Copied from here and here

Create the starter Flutter app

$ flutter create starter
$ cd starter

Run Flutter App on the Web

$ flutter config --enable-web
$ flutter config --enable-web
$ flutter build web

Run Flutter App on Android Emulator

$ flutter devices
$ flutter run [--verbose]
$ flutter emulators
5 available emulators:

Android_Accelerated_Oreo
Nexus_5X_API_28_x86      • Nexus 5X      • Google • Nexus 5X API 28 x86
Pixel_3_API_28           • pixel_3       • Google • Pixel 3 API 28
Pixel_XL_API_28          • pixel_xl      • Google • Pixel XL API 28
apple_ios_simulator      • iOS Simulator • Apple

To run an emulator, run 'flutter emulators --launch <emulator id>'.
To create a new emulator, run 'flutter emulators --create [--name xyz]'.
$ flutter emulators --launch apple_ios_simulator

Read More

Official website: https://flutter.io/ will supply from step by step to install and start with the simple example.

Dart language

Flutter training online

Google CodeLab: https://codelabs.developers.google.com/?cat=Flutter

Flutter Samples: https://github.com/flutter/samples

Flutter Cookbook: https://flutter.dev/docs/cookbook

Github Awesome-Flutter

Flutter challenge series has been building by Matt Carroll who is owners of Fluttery (Youtube channel https://www.youtube.com/fluttery)

Blogs 

App builder: It is an amazing tool to build the Flutter UI online that mean you only need choose your UI widget and drag to screen -> You can get the source code for your app.

The Flutter Pub is a medium publication to bring you the latest and amazing resources such as articles, videos, codes, podcasts, etc. about this great

What’s next

  • Learn Dart
    Go to Dart guides and see a preview of the four most visited websites. Initially, these two are worth focusing on: Language tour and Language samples. A complete and detailed Dart course supported by examples can also be found here.
  • Install Flutter SDK – Prepare IDE
    The entire process is described step by step depending on the system on which we want to install Flutter.
  • Study Material Design Concept
    If we want to create user-friendly interfaces, it is important to read material design rules. 
  • Widgets
    Widgets are an indispensable part of Flutter. You can browse them alphabetically.
  • API Calls and Database Integration
    The Pub provides great packages such as: http or dio to perform HTTP requests. Hive is a lightweight and blazing fast key-value database written in pure Dart. You should also consider integrating with Firebase.

Links