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

Changing layout properties during runtime


In Android development, it's generally the preferred practice to define the UI with XML and the application code in Java, keeping the user interface code separate from the application code. There are times where it is much easier or more efficient, to alter (or even build) the UI from the Java code. Fortunately, this is easily supported in Android.

In this recipe, we will obtain a reference to the LayoutParams object to change the margin during runtime.

Getting ready

Here, we will set up a simple layout with XML and use a LinearLayout.LayoutParams object to change the margins of a View during runtime.  Create a new project using with an Empty Activity called RuntimeProperties. Use the default Phone & Tablet settings on the Target Android devices and select Empty Activity on the Add an Activity to Mobile dialog.

How to do it...

We can create or manipulate any of the standard layouts or controls through code. For this example, we will work with LinearLayout...