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You're reading from Android Studio 4.1 Development Essentials – Kotlin Edition

Product type Book

Published in May 2021

Publisher Packt

ISBN-13 9781801815987

Pages 822 pages

Edition 1st Edition

Languages

Concepts

Android Development

Author (1):

Neil Smyth

Table of Contents (95) Chapters

1. Introduction

2. Setting up an Android Studio Development Environment

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

84. Printing with the Android Printing Framework

With the introduction of the Android 4.4 KitKat release, it became possible to print content from within Android applications. While subsequent chapters will explore in more detail the options for adding printing support to your own applications, this chapter will focus on the various printing options now available in Android and the steps involved in enabling those options. Having covered these initial topics, the chapter will then provide an overview of the various printing features that are available to Android developers in terms of building printing support into applications.

84.1 The Android Printing Architecture

Printing in Android is provided by the Printing framework. In basic terms, this framework consists of a Print Manager and a number of print service plugins. It is the responsibility of the Print Manager to handle the print requests from applications on the device and to interact with the print service plugins that are installed on the device, thereby ensuring that print requests are fulfilled. By default, many Android devices have print service plugins installed to enable printing using the Google Cloud Print and Google Drive services. Print Services Plugins for other printer types, if not already installed, may also be obtained from the Google Play store. Print Service Plugins are currently available for HP, Epson, Samsung and Canon printers and plugins from other printer manufactures will most likely be released in the future though the Google Cloud Print service plugin can also be used to print from an Android device to just about any printer...

84.2 The Print Service Plugins

The purpose of the Print Service plugins is to enable applications to print to compatible printers that are visible to the Android device via a local area wireless network or Bluetooth.

The presence of the Print Service Plugin on an Android device can be verified by loading the Google Play app and performing a search for “Print Service Plugin”. Once the plugin is listed in the Play Store, and in the event that the plugin is not already installed, it can be installed by selecting the Install button. Figure 84-1, for example, shows the HP Print Service plugin within Google Play.

The Print Services plugins will automatically detect compatible printers on the network to which the Android device is currently connected and list them as options when printing from an application.

Figure 84-1

84.3 Google Cloud Print

Google Cloud Print is a service provided by Google that enables you to print content onto your own printer over the web from anywhere with internet connectivity. Google Cloud Print supports a wide range of devices and printer models in the form of both Cloud Ready and Classic printers. A Cloud Ready printer has technology built-in that enables printing via the web. Manufacturers that provide cloud ready printers include Brother, Canon, Dell, Epson, HP, Kodak and Samsung. To identify if your printer is both cloud ready and supported by Google Cloud Print, review the list of printers at the following URL:

https://www.google.com/cloudprint/learn/printers.html

In the case of classic, non-Cloud Ready printers, Google Cloud Print provides support for cloud printing through the installation of software on the computer system to which the classic printer is connected (either directly or over a home or office network).

To set up Google Cloud Print, visit the...

84.4 Printing to Google Drive

In addition to supporting physical printers, it is also possible to save printed output to your Google Drive account. When printing from a device, select the Save to Google Drive option in the printing panel. The content to be printed will then be converted to a PDF file and saved to the Google Drive cloud-based storage associated with the currently active Google Account ID on the device.

84.5 Save as PDF

The final printing option provided by Android allows the printed content to be saved locally as a PDF file on the Android device. Once selected, this option will request a name for the PDF file and a location on the device into which the document is to be saved.

Both the Save as PDF and Google Drive options can be invaluable in terms of saving paper when testing the printing functionality of your own Android applications.

84.6 Printing from Android Devices

Google recommends that applications which provide the ability to print content do so by placing the print option in the Overflow menu. A number of applications bundled with Android now include “Print…” menu options. Figure 84-2, for example, shows the Print option accessed by selecting the “Share…” option in the Overflow menu of the Chrome browser application:

Figure 84-2

Once the print option has been selected from within an application, the standard Android print screen will appear showing a preview of the content to be printed as illustrated in Figure 84-3:

Figure 84-3

Tapping the panel along the top of the screen will display the full range of printing options:

Figure 84-4

The Android print panel provides the usual printing options such as paper size, color, orientation and number of copies. Other print destination options may be accessed by tapping on the current printer...

84.7 Options for Building Print Support into Android Apps

The Printing framework provides a number of options for incorporating print support into Android applications. These options can be categorized as follows:

84.7.1 Image Printing

As the name suggests, this option allows image printing to be incorporated into Android applications. When adding this feature to an application, the first step is to create a new instance of the PrintHelper class:

val imagePrinter = PrintHelper(context)

Next, the scale mode for the printed image may be specified via a call to the setScaleMode() method of the PrintHelper instance. Options are as follows:

•SCALE_MODE_FIT – The image will be scaled to fit within the paper size without any cropping or changes to aspect ratio. This will typically result in white space appearing in one dimension.

•SCALE_MODE_FILL – The image will be scaled to fill the paper size with cropping performed where necessary to avoid...

84.8 Summary

The Android SDK includes the ability to print content from within a running app. Print output can be directed to suitably configured printers, a local PDF file or to the cloud via Google Drive. From the perspective of the Android application developer, these capabilities are available for use in applications by making use of the Printing framework. By far the easiest printing options to implement are those involving content in the form of images and HTML. More advanced printing may, however, be implemented using the custom document printing features of the framework.