Category: Kotlin

The preservation and restoration of app state is about presenting the user with continuity in appearance and behavior after an app is placed in the background. Users expect to be able to switch from one app to another and, on returning to the original app, find it in the exact state it was in before…

So far in this book, we have covered the basic concepts of modern Android app architecture and looked in more detail at the ViewModel and LiveData components. The concept of data binding was also covered in the previous chapter and will now be used in this chapter to modify the ViewModelDemo app further. Removing the…

In the chapter entitled Modern Android App Architecture with Jetpack, we introduced the concept of Android Data Binding. We explained how it is used to directly connect the views in a user interface layout to the methods and data located in other objects within an app without the need to write code. This chapter will…

The previous chapter began building an app to conform to the recommended Jetpack architecture guidelines. These initial steps involved implementing the data model for the app user interface within a ViewModel instance. This chapter will further enhance the app design using the LiveData architecture component. Once LiveData support has been added to the project in…

The previous chapter introduced the fundamental concepts of Android Jetpack and outlined the basics of modern Android app architecture. Jetpack defines a set of recommendations describing how an Android app project should be structured while providing a set of libraries and components that make it easier to conform to these guidelines to develop reliable apps…

For many years, Google did not recommend a specific approach to building Android apps other than to provide tools and development kits while letting developers decide what worked best for a particular project or individual programming style. That changed in 2017 with the introduction of the Android Architecture Components, which, in turn, became part of…

As outlined in the previous chapter, fragments provide a convenient mechanism for creating reusable modules of application functionality consisting of both sections of a user interface and the corresponding behavior. Once created, fragments can be embedded within activities. Having explored the general theory of fragments in the previous chapter, this chapter aims to create an…

As you progress through the chapters of this book, it will become increasingly evident that many of the design concepts behind the Android system were conceived to promote the reuse of and interaction between the different elements that make up an application. One such area that will be explored in this chapter involves using Fragments.…

The previous chapter covered the detection of what is referred to as “common gestures” from within an Android application. In practice, however, a gesture can conceivably involve just about any sequence of touch motions on the display of an Android device. In recognition of this, the Android SDK allows custom gestures of just about any…

The term “gesture” defines a contiguous sequence of interactions between the touch screen and the user. A typical gesture begins at the point that the screen is first touched and ends when the last finger or pointing device leaves the display surface. When correctly harnessed, gestures can be implemented to communicate between the user and…