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You're reading from Android Studio 4.1 Development Essentials – Kotlin Edition Developing Android 11 Apps Using Android Studio 4.1, Kotlin, and Android Jetpack

Product type Paperback

Published in May 2021

Publisher Packt

ISBN-13 9781801815987

Length 822 pages

Edition 1st Edition

Languages

Kotlin

Tools

Android

Concepts

Android Development

Author (1):

Neil Smyth

View More author details

Table of Contents (95) Chapters

1. Introduction

2. Setting up an Android Studio Development Environment FREE CHAPTER

3. Creating an Example Android App in Android Studio

4. Creating an Android Virtual Device (AVD) in Android Studio

5. Using and Configuring the Android Studio AVD Emulator

6. A Tour of the Android Studio User Interface

7. Testing Android Studio Apps on a Physical Android Device

8. The Basics of the Android Studio Code Editor

9. An Overview of the Android Architecture

10. The Anatomy of an Android Application

11. An Introduction to Kotlin

12. Kotlin Data Types,Variables and Nullability

13. Kotlin Operators and Expressions

14. Kotlin Flow Control

15. An Overview of Kotlin Functions and Lambdas

16. The Basics of Object Oriented Programming in Kotlin

17. An Introduction to Kotlin Inheritance and Subclassing

18. An Overview of Android View Binding

19. Understanding Android Application and Activity Lifecycles

20. Handling Android Activity State Changes

21. Android Activity State Changes by Example

22. Saving and Restoring the State of an Android Activity

23. Understanding Android Views, View Groups and Layouts

24. A Guide to the Android Studio Layout Editor Tool

25. A Guide to the Android ConstraintLayout

26. A Guide to using ConstraintLayout in Android Studio

27. Working with ConstraintLayout Chains and Ratios in Android Studio

28. An Android Studio Layout Editor ConstraintLayout Tutorial

29. Manual XML Layout Design in Android Studio

30. Managing Constraints using Constraint Sets

31. An Android ConstraintSet Tutorial

32. A Guide to using Apply Changes in Android Studio

33. An Overview and Example of Android Event Handling

34. Android Touch and Multi-touch Event Handling

35. Detecting Common Gestures using the Android Gesture Detector Class

36. Implementing Custom Gesture and Pinch Recognition on Android

37. An Introduction to Android Fragments

38. Using Fragments in Android Studio - An Example

39. Modern Android App Architecture with Jetpack

40. An Android Jetpack ViewModel Tutorial

41. An Android Jetpack LiveData Tutorial

42. An Overview of Android Jetpack Data Binding

43. An Android Jetpack Data Binding Tutorial

44. An Android ViewModel Saved State Tutorial

45. Working with Android Lifecycle-Aware Components

46. An Android Jetpack Lifecycle Awareness Tutorial

47. An Overview of the Navigation Architecture Component

48. An Android Jetpack Navigation Component Tutorial

49. An Introduction to MotionLayout

50. An Android MotionLayout Editor Tutorial

51. A MotionLayout KeyCycle Tutorial

52. Working with the Floating Action Button and Snackbar

53. Creating a Tabbed Interface using the TabLayout Component

54. Working with the RecyclerView and CardView Widgets

55. An Android RecyclerView and CardView Tutorial

56. A Layout Editor Sample Data Tutorial

57. Working with the AppBar and Collapsing Toolbar Layouts

58. An Android Studio Master/Detail Flow Tutorial

59. An Overview of Android Intents

60. Android Explicit Intents – A Worked Example

61. Android Implicit Intents – A Worked Example

62. Android Broadcast Intents and Broadcast Receivers

63. A Basic Overview of Threads and AsyncTasks

64. An Introduction to Kotlin Coroutines

65. An Android Kotlin Coroutines Tutorial

66. An Overview of Android Started and Bound Services

67. Implementing an Android Started Service – A Worked Example

68. Android Local Bound Services – A Worked Example

69. Android Remote Bound Services – A Worked Example

70. An Android Notifications Tutorial

71. An Android Direct Reply Notification Tutorial

72. Foldable Devices and Multi-Window Support

73. An Overview of Android SQLite Databases

74. The Android Room Persistence Library

75. An Android TableLayout and TableRow Tutorial

76. An Android Room Database and Repository Tutorial

77. Accessing Cloud Storage using the Android Storage Access Framework

78. An Android Storage Access Framework Example

79. Video Playback on Android using the VideoView and MediaController Classes

80. Android Picture-in-Picture Mode

81. An Android Picture-in-Picture Tutorial

82. Making Runtime Permission Requests in Android

83. Android Audio Recording and Playback using MediaPlayer and MediaRecorder

84. Printing with the Android Printing Framework

85. An Android HTML and Web Content Printing Example

86. A Guide to Android Custom Document Printing

87. An Introduction to Android App Links

88. An Android Studio App Links Tutorial

89. A Guide to the Android Studio Profiler

90. An Android Biometric Authentication Tutorial

91. Creating, Testing and Uploading an Android App Bundle

92. An Overview of Android Dynamic Feature Modules

93. An Android Studio Dynamic Feature Tutorial

94. An Overview of Gradle in Android Studio

Index

18.1 Find View by ID and Synthetic Properties

As outlined in the chapter entitled “The Anatomy of an Android Application”, all of the resources that make up an application are compiled into a class named R. Amongst those resources are those that define layouts. Within the R class is a subclass named layout, which contains the layout resources, including the views that make up the user interface. Most apps will need to implement interaction between the code and these views, for example when reading the value entered into the EditText view or changing the content displayed on a TextView.

Over the years, a number of different approaches to referencing layout views have been introduced. The oldest option involves writing code to manually find a view based on its id via a method named findViewById(). For example:

val myTextView: TextView = findViewById(R.id.myTextView)

With the reference obtained, the properties of the view can then be accessed. For example:

myTextView...