The document emphasizes the importance of developing maintainable apps by focusing on code quality, proper domain design, and effective library selection. It provides guidelines for ensuring readability and testing standards, advocating for practices like unit testing and continuous integration. Additionally, it offers resources for further learning on clean code and effective programming strategies.

1. Be a Good Citizen:
!
Develop Maintainable Apps

2. “…a high probability of determining the cause of
a problem in a timely manner… and a high
probability of being able to modify the program
without causing an error in some other part…”
— IEEE

3. Why Care?

9. What’s involved…
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10. What’s involved…
Libraries
1
@brwngrldev

11. What’s involved…
Libraries
1
Domain
Design
2
@brwngrldev

12. What’s involved…
Libraries
1
Domain
Design
2
Code
Quality
3
@brwngrldev

13. What’s involved…
Libraries
1
Domain
Design
2
Code
Quality
3
Testing
4
@brwngrldev

14. Choosing the Right Library

15. So many options

16. So many options

17. What to consider
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18. What to consider
Documentation
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19. What to consider
Documentation
Project Stability
@brwngrldev

20. What to consider
Documentation
Project Stability
Fulfills a Need
@brwngrldev

21. What to consider
Amazing App
!
Documentation
Project Stability
Fulfills a Need
@brwngrldev

22. Example

23. So you need images…

24. So you need images…
Volley
!
Fresco
!
Glide
!
Picasso
!

25. Volley
!

26. Documentation
s
Volley
!

29. Documentation
s
Volley
!

30. Documentation
s
W Project Stability
Volley
!

32. Documentation
s
W Project Stability
Volley
!

33. Documentation
s
W Project Stability
p Fulfills a need
Volley
!

34. @brwngrldev

35. Rinse & Repeat
Volley
!
Fresco
!
Glide
!
Picasso
!

36. Review…
• Documentation
• Repository Check-ins
• Fulfills a Need
Libraries
1
@brwngrldev

37. Domain Design

38. Doing too much

39. Doing too much

40. Seen this?

41. Seen this?

42. Seen this?

43. Seen this?

44. How to fix this

45. Clean
It Up!
How to fix this

46. Clean
It Up!
How to fix this
MVP
MVVM
OO

47. Foo
What’s involved…

48. What’s involved…
Foo Bar
Baz Lol
Omg

49. Example

50. Remember this?

51. We need tests

52. We need tests

53. We need tests

54. Extract a Presenter

55. Create an Interface

56. Reference the Interface

57. Implement the Interface

58. Foo Bar
Baz Lol
Omg
@brwngrldev

59. Review…
• Keep Code Simple
• Use MV* Pattern
• Functional Tests
• Use the Tools
@brwngrldev
Domain
Design
2

60. Code Quality

61. Poor Readability

62. Poor Readability

63. Increase Readability?

64. Increase Readability?
“Checkstyle is a development tool to
help programmers write Java code
that adheres to a coding standard.”

65. Source
Files
config.xml
Checkstyle Tool
!
Modules
Design
Formatting
Code Complexity

66. apply plugin: ‘checkstyle’
!
task checkstyle(type: Checkstyle) {
description 'Checks if the code passes quality standards'
group 'verification'
configFile file(‘checkstyle.xml')
…
}

67. apply plugin: ‘checkstyle’
!
task checkstyle(type: Checkstyle) {
description 'Checks if the code passes quality standards'
group 'verification'
configFile file(‘checkstyle.xml')
…
}

68. <module name=“MethodLength">
<property name="max" value=“60"/>
</module>
<module name=“LineLength">
<property name="max" value=“120"/>
</module>
<module name=“CyclomaticComplexity">
<property name="max" value=“8"/>
</module>
…

69. <module name=“MethodLength">
<property name="max" value=“60"/>
</module>
<module name=“LineLength">
<property name="max" value=“120"/>
</module>
<module name=“CyclomaticComplexity">
<property name="max" value=“8"/>
</module>
…

70. <module name=“MethodLength">
<property name="max" value=“60"/>
</module>
<module name=“LineLength">
<property name="max" value=“120"/>
</module>
<module name=“CyclomaticComplexity">
<property name="max" value=“8"/>
</module>
…
playerControlConfig.setShowClosedCaptionsButton(a.getBo
!

71. <module name=“MethodLength">
<property name="max" value=“60"/>
</module>
<module name=“LineLength">
<property name="max" value=“120"/>
</module>
<module name=“CyclomaticComplexity">
<property name="max" value=“8"/>
</module>
…
leable.WapoVideoView_showClosedCaptionsButton, false));

72. <module name=“MethodLength">
<property name="max" value=“60"/>
</module>
<module name=“LineLength">
<property name="max" value=“120"/>
</module>
<module name=“CyclomaticComplexity">
<property name="max" value=“8"/>
</module>
…

73. <module name=“MethodLength">
<property name="max" value=“60"/>
</module>
<module name=“LineLength">
<property name="max" value=“120"/>
</module>
<module name=“CyclomaticComplexity">
<property name="max" value=“8"/>
</module>
…

74.
<module name=“CyclomaticComplexity">
<property name="max" value=“8"/>
</module>
!

75. M = E − N + 2P
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76. M = E − N + 2P
@brwngrldev

77. Example

78. public void overlyComplexMethod(Video video) {
if (video != null && video.getStreamUrl() != null) {
switch (video.getCategory()) {
case "CAT1" :
playVideo(video);
if (video.getLargeImageUrl() == null) {
video.setLargeImageUrl("http://www.largeImage.png");
}
updateMetadata(video);
break;
case "CAT2" :
if (video.getLargeImageUrl() == null) {
video.setLargeImageUrl("http://www.smallImage.png");

79. case "CAT1" :
playVideo(video);
if (video.getLargeImageUrl() == null) {
video.setLargeImageUrl("http://www.largeImage.png");
}
updateMetadata(video);
break;
case "CAT2" :
if (video.getLargeImageUrl() == null) {
video.setLargeImageUrl("http://www.smallImage.png");
}
updateMetadata(video);
break;
…

80. … warning: Cyclomatic Complexity is 9

81. public void overlyComplexMethod(Video video) {
if (video != null && video.getStreamUrl() != null) {
updateVideoBasedOnCategory(video);
}
}
!
private void updateVideoBasedOnCategory(Video video) {
switch (video.getCategory()) {
case "CAT1" :
playVideo(video);
if (video.getLargeImageUrl() == null) {
video.setLargeImageUrl("http://www.largeImage.png");
}
updateMetadata(video);
break;

82. public void overlyComplexMethod(Video video) {
if (video != null && video.getStreamUrl() != null) {
updateVideoBasedOnCategory(video);
}
}
!
private void updateVideoBasedOnCategory(Video video) {
switch (video.getCategory()) {
case "CAT1" :
playVideo(video);
if (video.getLargeImageUrl() == null) {
video.setLargeImageUrl("http://www.largeImage.png");
}
updateMetadata(video);
break;

83. public void overlyComplexMethod(Video video) {
if (video != null && video.getStreamUrl() != null) {
updateVideoBasedOnCategory(video);
}
}
!
private void updateVideoBasedOnCategory(Video video) {
switch (video.getCategory()) {
case "CAT1" :
playVideo(video);
if (video.getLargeImageUrl() == null) {
video.setLargeImageUrl("http://www.largeImage.png");
}
updateMetadata(video);
break;
7

84. !
switch (video.getCategory()) {
case "CAT1" :
playVideo(video);
updateMetaDataAndUrl(video, "http://www.largeImage.png");
break;
…
@brwngrldev

85. !
switch (video.getCategory()) {
case "CAT1" :
playVideo(video);
updateMetaDataAndUrl(video, "http://www.largeImage.png");
break;
…
4
@brwngrldev

86. Review…
• Readability Matters
• Use Checkstyle
• Refactor Gradually
@brwngrldev
Code
Quality
3

87. Unit Testing

88. Untested Code

89. Untested Code

90. “Every single line of code that you
write should be tested. Period.”
— Robert Martin

92. 0
9,000
18,000
27,000
36,000
Lines of Code
Production Tests
FitNesse

93. 0
9,000
18,000
27,000
36,000
Lines of Code
Production Tests 90%
FitNesse

94. 0
9,000
18,000
27,000
36,000
Lines of Code
Production Tests 90%
2,200
FitNesse

95. 0
9,000
18,000
27,000
36,000
Lines of Code
Production Tests 90%
2,200
90s
FitNesse

99. Example

100. Test Setup
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101. Sample Test
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102. Test Report

103. Continuous Integration
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104. Code Coverage
@brwngrldev

105. Makes You Powerful

106. Review
• Listen to Robert Martin!
• JUnit + Mockito
• Continuous Integration
• Code Coverage
Testing
4
@brwngrldev

107. Summary

108. Summary
Choose the right library

109. Summary
Choose the right library
Don’t do too much

110. Summary
Ensure code quality
Choose the right library
Don’t do too much

111. Summary
Ensure code quality
Choose the right library
Don’t do too much
Write unit tests

112. Resources
• Clean Code - http://amzn.to/1DJybxH
• Effective Java - http://amzn.to/1Ku8Xel
• Working Effectively with Legacy Code - http://amzn.to/1Jqe1PA
• Unit Testing Idioms - http://goo.gl/Bx1WbL
• Google Code Style - http://goo.gl/8Pf6J3
• Architecting Android - http://goo.gl/UKvmbq
• Conquering Cyclomatic Complexity - http://goo.gl/lRoPXN
• PostTV App - https://goo.gl/0TRsXU
@brwngrldev

113. Photo Credits
• Slide 4 - https://www.flickr.com/photos/nikigunn/8379494330
• Slide 6 - https://www.flickr.com/photos/tracy_olson/61056391
• Slide 7 - https://en.wikipedia.org/wiki/Dominoes
• Slide 10 - https://www.flickr.com/photos/tshirbert/118250140
• Slide 24 - http://uncompromisedmen.com/2015/02/17/top-10-crazy-beards-
wish-youd-seen-person/
• Slide 38 - https://www.flickr.com/photos/cast_fish/2888442781
• Slide 52 - https://www.flickr.com/photos/desertbusforhope/8207412726/
• Slide 54 - https://www.flickr.com/photos/sokabs/2668975758
• Slide 63 - https://www.flickr.com/photos/pasukaru76/5268559005
@brwngrldev