Book Image

Android 9 Development Cookbook - Third Edition

By : Rick Boyer
Book Image

Android 9 Development Cookbook - Third Edition

By: Rick Boyer

Overview of this book

The Android OS has the largest installation base of any operating system in the world. There has never been a better time to learn Android development to write your own applications, or to make your own contributions to the open source community! With this extensively updated cookbook, you'll find solutions for working with the user interfaces, multitouch gestures, location awareness, web services, and device features such as the phone, camera, and accelerometer. You also get useful steps on packaging your app for the Android Market. Each recipe provides a clear solution and sample code you can use in your project from the outset. Whether you are writing your first app or your hundredth, this is a book that you will come back to time and time again, with its many tips and tricks on the rich features of Android Pie.
Table of Contents (24 chapters)
Title Page
Copyright and Credits
Dedication
About Packt
Contributors
Preface
Index

Creating a Home screen widget


Before we dig into the code for creating an App Widget, let's cover the basics. There are three required and one optional component:

  • The AppWidgetProviderInfo file: It's an XML resource (described later)
  • The AppWidgetProvider class: This is a Java class
  • The View layout file: It's a standard layout XML file, with some restrictions (explained later)
  • The App Widget configuration Activity (optional): This is an Activity the OS will launch when placing the widget to provide configuration options

The AppWidgetProvider must also be declared in the AndroidManifest file. Since AppWidgetProvider is a helper class based on the Broadcast Receiver, it is declared in the manifest with the <receiver> element. Here is an example manifest entry:

<receiver android:name=".HomescreenWidgetProvider" >
    <intent-filter>
        <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
    </intent-filter>
    <meta-data android:name="android...