10/12/2021 Google Vs Chrome App
When Chrome OS launched it was essentially Google's Chrome web browser. For those used to an operating system like WIndows and Mac, it made the average Chromebook seem like little more than a. Get more done with the new Google Chrome. A more simple, secure, and faster web browser than ever, with Googleâs smarts built-in. A new report from Bloomberg details Googleâs plan of bringing a âslightly stringentâ version of app tracking to Android. The report says that Google is trying to âfind a balanceâ between the rising demands of privacy-conscious consumers and advertisers.
Sometimes it's hard to decide whether you need to publish a hosted app or a Chrome Appâor maybe even an Chrome Extension. This page aims to help you choose the right type of app.
Overview #
As the following figure shows, if you already have a web app, you don't need to change it; you can just publish it as a hosted app. If you're willing to modify your app or build one from scratch, you have more options.
Note: 2GB is the current size limit for packaged apps. If your app (with all its essential assets) can't fit into a 2GB ZIP file, then your app is too big to be a packaged app.
Details #
If you're having trouble deciding what type of app to create, read the article Extensions, Packaged Apps, and Hosted Apps in the Chrome Web Store. Here's some additional information to help you choose:
Flutter is Google's UI toolkit for building beautiful, natively compiled applications for mobile, web, and desktop from a single codebase. Flutter works with existing code, is used by developers and organizations around the world, and is free and open source.
In this codelab, you'll create a simple mobile Flutter app. If you're familiar with object-oriented code and basic programming conceptsâsuch as variables, loops, and conditionalsâthen you can complete the codelab. You don't need previous experience with Dart, mobile, or web programming.
In part 2 of this codelab, you'll add interactivity, modify the app's theme, and add the ability to navigate to a new page (called a route in Flutter).
You'll implement a simple app that generates proposed names for a startup company. The user can select and unselect names, saving the best ones. The code lazily generates 10 names at a time. As the user scrolls, more names are generated. There is no limit to how far a user can scroll.
The following animated GIF shows how the app works at the completion of part:
What would you like to learn from this codelab?I'm new to the topic, and I want a good overview.I know something about this topic, but I want a refresher.I'm looking for example code to use in my project.I'm looking for an explanation of something specific.
You need two pieces of software to complete this labâthe Flutter SDK and an editor. (The codelab assumes that you're using Android Studio, but you can use your preferred editor.)
You can run the codelab by using any of the following devices:
You need only run the
config command once. After enabling web support, every Flutter app you create also compiles for the web. In your IDE under the devices pulldown, or at the command line using flutter devices , you should now see Chrome and Web server listed. The Chrome device automatically starts Chrome. The Web server starts a server that hosts the app so that you can load it from any browser. Use the Chrome device during development so that you can use DevTools, and the web server when you want to test on other browsers. For more information, see Building a web application with Flutter and Write your first Flutter app on the web.
Create a simple, templated Flutter app. Create a Flutter project called startup_namer and migrate to null safety as follows.
You'll mostly edit
lib/main.dart , where the Dart code lives.
Replace the contents of
lib/main.dart . Delete all of the code from lib/main.dart and replace it with the following code, which displays 'Hello World' in the center of the screen.
Tip: When pasting code into your app, indentation can become skewed. You can fix it with the following Flutter tools:
Run the app. You should see either Android, iOS, or web output, depending on your device.
Tip: The first time that you run on a physical device, it can take a while to load. Afterward, you can use hot reload for quick updates. In supported IDEs, Save also performs a hot reload if the app is running. When running an app directly from the console using
flutter run , enter r to perform hot reload.
Observations
In this step, you'll start using an open-source package named
english_words , which contains a few thousand of the most-used English words, plus some utility functions.
You can find the
english_words package, as well as many other open-source packages, at pub.dev.
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The pubspec file manages the assets for a Flutter app. In
pubspec.yaml , append english_words: ^4.0.0-0 (english_words 4.0.0-0 or higher) to the dependencies list:
While viewing the pubspec in Android Studio's editor view, click Packages get. This pulls the package into your project. You should see the following in the console:
Performing
dart pub get also auto-generates the pubspec.lock file with a list of all packages pulled into the project and their version numbers.
In
lib/main.dart , import the new package:
As you type, Android Studio gives you suggestions for libraries to import. It then renders the import string in gray, letting you know that the imported library is unused (so far).
Next, you'll use the
english_words package to generate the text instead of using 'Hello World'.
Make the following changes:
Tip: Pascal case (also known as upper camel case) means that each word in the string, including the first one, begins with an uppercase letter. So,
uppercamelcase becomes UpperCamelCase .
If the app is running, hot reload to update the running app. (From the command line, you can enter
r to hot reload.) Each time you click hot reload or save the project, you should see a different word pair, chosen at random, in the running app. That's because the word pairing is generated inside the build method, which runs each time the MaterialApp requires rendering, or when toggling the Platform in the Flutter Inspector.
Problems?
If your app isn't running correctly, look for typos. If needed, use the code at the following links to get back on track.
Stateless widgets are immutable, meaning that their properties can't changeâall values are final.
Stateful widgets maintain state that might change during the lifetime of the widget. Implementing a stateful widget requires at least two classes: 1) a
StatefulWidget that creates an instance of a State class. The StatefulWidget object is, itself, immutable and can be thrown away and regenerated, but the State object persists over the lifetime of the widget.
In this step, you'll add a stateful widget,
RandomWords , which creates its State class, _RandomWordsState . You'll then use RandomWords as a child inside the existing MyApp stateless widget.
Create boilerplate code for a stateful widget.
It can go anywhere in the file outside of
MyApp , but the solution places it at the bottom of the file. In lib/main.dart , position your cursor after all of the code, enter Return a couple times to start on a fresh line. In your IDE, start typing stful . The editor asks if you want to create a Stateful widget. Press Return to accept. The boilerplate code for two classes appears, and the cursor is positioned for you to enter the name of your stateless widget.
Enter
RandomWords as the name of your widget.
As you can see in the code below, the
RandomWords widget does little else beside creating its State class.
Once you've entered
RandomWords as the name of the stateful widget, the IDE automatically updates the accompanying State class, naming it _RandomWordState . By default, the name of the State class is prefixed with an underscore. Prefixing an identifier with an underscore enforces privacy in the Dart language and is a recommended best practice for State objects.
The IDE also automatically updates the state class to extend
State<RandomWords> , indicating that you're using a generic State class specialized for use with RandomWords . Most of the app's logic resides hereâ âit maintains the state for the RandomWords widget. This class saves the list of generated word pairs, which grows infinitely as the user scrolls and, in part 2 of this lab, favorites word pairs as the user adds or removes them from the list by toggling the heart icon.
Both classes now look as follows:
Update the
build() method in _RandomWordsState .
Replace
return Container(); with the following two lines:
Remove the word-generation code from
MyApp by making the following changes:
Hot reload the app. The app should behave as before, displaying a word pairing each time you hot reload or save the app.
Tip: If you see a warning on a hot reload that you might need to restart the app, you should consider restarting the app. It might be a false positive, but restarting ensures that your changes are reflected in the app's UI.
Problems?
If your app isn't running correctly, you can use the code at the following link to get back on track.
In this step, you'll expand
_RandomWordsState to generate and display a list of word pairings. As the user scrolls, the list (displayed in a ListView widget) grows infinitely. The builder factory constructor in ListView allows you to lazily build a list view on demand.
Add some state variables to the
_RandomWordState class.
Add a
_suggestions list for saving suggested word pairings. Also, add a _biggerFont variable for making the font size larger.
Next, you'll add a
_buildSuggestions() function to the _RandomWordsState class. This method builds the ListView that displays the suggested word pairing.
The
ListView class provides a builder property, itemBuilder , that's a factory builder and callback function specified as an anonymous function. Two parameters are passed to the functionâthe BuildContext and the row iterator, i . The iterator begins at 0 and increments each time the function is called, once for every suggested word pairing. This model allows the suggestion list to continue growing as the user scrolls.
Add the entire
_buildSuggestions function.
In the
_RandomWordsState class, add the following function, deleting the comments, if you prefer:
The
_buildSuggestions function calls _buildRow once per word pair. That function displays each new pair in a ListTile , which allows you to make the rows more attractive in part 2.
Add a
_buildRow function to _RandomWordsState :
Update the
build method for _RandomWordsState.
Change it to use
_buildSuggestions() , rather than directly calling the word-generation library. ( Scaffold implements the basic Material Design visual layout.)
Update the
build method for MyApp , changing the title, removing the AppBar , and changing the home property to a RandomWords widget.
Restart the app. You should see a list of word pairings no matter how far you scroll.
Problems?
If your app isn't running correctly, you can use the code at the following link to get back on track.
When part 2 is completed, the app will look like this:
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