Inside Jetpack Architecture Components

How LifecycleObservers, LiveData, ViewModels work

Transcript

1. )JSPZVLJ.PSJ
   !NPSJESPJE
   *OTJEF+FUQBDL
   "SDIJUFDUVSF$PNQPOFOUT
   

   View Slide

2. "7FOUVSFCFUXFFO4PGUCBOLBOE:BIPP
   0OFPGCJHHFTUTFBSDIJO+BQBO
   

   View Slide

3. "SDIJUFDUVSF
   $PNQPOFOUT
   

   View Slide

4. -JGFDZDMFT
   -JWF%BUB
   7JFX.PEFM
   3PPN
   1BHJOH
   %BUB#JOEJOH
   /BWJHBUJPO
   8PSL.BOBHFS
   %PXOMPBE.BOBHFS
   .FEJB1MBZCBDL
   1FSNJTTJPOT
   /PUJDBUJPOT
   4IBSJOH
   4MJDFT
   "OJNBUJPO5SBOTJUJPOT
   "VUP 578FBS
   &NPKJ
   'SBHNFOU
   -BZPVU
   1BMFUUF
   "QQ$PNQBU
   "OESPJE,59
   .VMUJEFY
   5FTU
   

   View Slide

5. -JGFDZDMFT
   -JWF%BUB
   7JFX.PEFM
   3PPN
   1BHJOH
   %BUB#JOEJOH
   /BWJHBUJPO
   8PSL.BOBHFS
   "QQ$PNQBU
   "OESPJE,59
   

   View Slide

6. -JGFDZDMFT
   -JWF%BUB
   7JFX.PEFM
   3PPN
   1BHJOH
   %BUB#JOEJOH
   /BWJHBUJPO
   8PSL.BOBHFS
   "QQ$PNQBU
   "OESPJE,59
   BOESPJEBSDIMJGFDZDMF
   

   View Slide

7. -JGFDZDMF1SPCMFNT
   JO"OESPJE
   

   View Slide

8. JOFBSMZEBZT
   

   View Slide

9. UPEBZ
   խ
   

   View Slide

10. DBTF
    UPVDIJOHEFTUSPZFE7JFX
    

    View Slide

11. DBTFUPVDIJOHEFTUSPZFE7JFX
    
    

    View Slide

12. DBTFUPVDIJOHEFTUSPZFE7JFX
    
    
    Cute Cat
    

    View Slide

13. DBTFUPVDIJOHEFTUSPZFE7JFX
    
    
    Cute Cat
    
    

    View Slide

14. Cute Cat
    DBTFUPVDIJOHEFTUSPZFE7JFX
    
    
    
    
    
    

    View Slide

15. DBTFUPVDIJOHEFTUSPZFE7JFX
    
    
    
    
    
    
    Cute Cat
    

    View Slide

16. DBTFUPVDIJOHEFTUSPZFE7JFX
    
    
    
    
    
    
    Cute Cat
    
    
    
    

    View Slide

17. DBTFUPVDIJOHEFTUSPZFE7JFX
    
    
    
    
    
    
    Cute Cat
    
    
    
    
    

    View Slide

18. DBTFUPVDIJOHEFTUSPZFE7JFX
    
    
    
    
    
    
    Cute Cat
    
    
    
    
    
    

    View Slide

19. DBTF
    GFUDIJOHBUFWFSZPO$SFBUF
    

    View Slide

20. Cute Cat
    DBTFGFUDIJOHBUFWFSZPO$SFBUF
    
    
    
    

    View Slide

21. The Japanese Bobtail is a breed of domestic cat
    with an unusual "bobbed" tail more closely
    resembling the tail of a rabbit than that of other
    cats. The variety is native to Japan and
    Southeast Asia, though it is now found
    throughout the world. The breed has been
    known in Japan for centuries, and it frequently
    appears in traditional folklore and art.
    Short Hair • Brown • White • Cute
    Caption
    Japanese Bobtail
    Cute Cat
    DBTFGFUDIJOHBUFWFSZPO$SFBUF
    
    
    
    
    
    

    View Slide

22. DBTFGFUDIJOHBUFWFSZPO$SFBUF
    
    
    
    
    
    
    Cute Cat
    

    View Slide

23. DBTFGFUDIJOHBUFWFSZPO$SFBUF
    
    
    
    
    
    
    Cute Cat
    
    
    
    
    

    View Slide

24. DBTFGFUDIJOHBUFWFSZPO$SFBUF
    
    
    
    
    
    
    Cute Cat
    
    
    
    
    
    

    View Slide

25. 
    Cute Cat
    DBTFGFUDIJOHBUFWFSZPO$SFBUF
    
    
    
    
    
    
    
    
    
    
    
    

    View Slide

26. DBTF
    EJTQPTJOHJOXSPOHXBZ
    

    View Slide

27. 
    DBTFEJTQPTJOHJOXSPOHXBZ
    Cute Cat
    Cute Cat
    

    View Slide

28. Cute Cat
    Cute Cat
    
    DBTFEJTQPTJOHJOXSPOHXBZ
    
    

    View Slide

29. Cute Cat
    Cute Cat
    
    DBTFEJTQPTJOHJOXSPOHXBZ
    
    
    

    View Slide

30. The Japanese Bobtail is a breed of domestic cat
    with an unusual "bobbed" tail more closely
    resembling the tail of a rabbit than that of other
    cats. The variety is native to Japan and
    Southeast Asia, though it is now found
    throughout the world. The breed has been
    known in Japan for centuries, and it frequently
    appears in traditional folklore and art.
    Short Hair • Brown • White • Cute
    Caption
    Japanese Bobtail
    Cute Cat
    
    DBTFEJTQPTJOHJOXSPOHXBZ
    
    
    
    
    
    
    
    

    View Slide

31. The Japanese Bobtail is a breed of domestic cat
    with an unusual "bobbed" tail more closely
    resembling the tail of a rabbit than that of other
    cats. The variety is native to Japan and
    Southeast Asia, though it is now found
    throughout the world. The breed has been
    known in Japan for centuries, and it frequently
    appears in traditional folklore and art.
    Short Hair • Brown • White • Cute
    Caption
    Japanese Bobtail
    Cute Cat
    
    DBTFEJTQPTJOHJOXSPOHXBZ
    
    
    
    
    
    
    
    
    

    View Slide

32. Cute Cat
    Cute Cat
    
    DBTFEJTQPTJOHJOXSPOHXBZ
    
    
    
    
    

    View Slide

33. Cute Cat
    Cute Cat
    
    DBTFEJTQPTJOHJOXSPOHXBZ
    
    
    
    
    
    

    View Slide

34. 4P XIBUXFTIPVE
    

    View Slide

35. DBTFUPVDIJOHEFTUSPZFE7JFX
    DBTFGFUDIJOHBUFWFSZPO$SFBUF
    DBTFEJTQPTJOHJOXSPOHXBZ
    

    View Slide

36. DBTFUPVDIJOHEFTUSPZFE7JFX
    DBTFGFUDIJOHBUFWFSZPO$SFBUF
    DBTFEJTQPTJOHJOXSPOHXBZ
    -JWF%BUB
    7JFX.PEFMT
    -JWF%BUB7JFX.PEFMT
    

    View Slide

37. -JGFDZDMF0CTFSWFS
    

    View Slide

38. 
    
    

    View Slide

39. 
    
     
    

    View Slide

40.  
    
    
    
    
     
    

    View Slide

41. TVCTDSJCF
    TVCTDSJCF
     
    
    
    
    
     
    

    View Slide

42. TVCTDSJCF
    TVCTDSJCF
     
    
    
    
    
     
    FWFOUIBQQFOT
    

    View Slide

43. SFFWFOUT
    SFFWFOUT
     
    
    
    
    
     
    FWFOUIBQQFOT
    

    View Slide

44. 
    
    

    View Slide

45. 
    
    
    

    View Slide

46. 
    
     
    

    View Slide

47. 
    
     
    

    View Slide

48. 
    
    
    

    View Slide

49. 
    
    
    
    

    View Slide

50. 
    
    
    
    
    

    View Slide

51. 
    
    
    
     
    

    View Slide

52. 
    
    
    
     
    
    
     
    

    View Slide

53. 
    
    
    
     
    
    
    

    View Slide

54. 
    
    
    
     
    
    
    

    View Slide

55. 
    
    
    
     
    
    
    &WFOU$IBOOFM
    

    View Slide

56. 
    
    
    
     
    
    
    

    View Slide

57. 
    
    
    
     
    
    
    1VCMJTIFS
    

    View Slide

58. 
    
    
    
     
    
    
    

    View Slide

59. 
    
    
    
     
    
    
    

    View Slide

60. 
    
    
    
     
    
    
    

    View Slide

61. 
    
    
    
     
    

    View Slide

62. -JGFDZDMF0CTFSWFS
    ٥0CTFSWFMJGFDZDMFT
    ٥%FTJHOFEBT1VC4VC
    ٥#PJMFSQMBUFGSFF
    ٥-JGFDZDMF"XBSF$PNQPOFOU
    

    View Slide

63. -JWF%BUB
    

    View Slide

64. 
    
    
    
    

    View Slide

65. 
    
    
    
    
    
    
    

    View Slide

66. 
    
    
    
    
    
     
    
    

    View Slide

67. 
    
    
    

    View Slide

68. 
    
    
    
    

    View Slide

69. 
    
    
    
    
    
    
    

    View Slide

70. 
    
    
    
    
    
     
    

    View Slide

71. 
    
    
    
    
    
     
    0O4UBSUFE
    0O3FTVNFE
    

    View Slide

72. 
    
    
    
    
    
     
    
    0O4UBSUFE
    0O3FTVNFE
    

    View Slide

73. 
    
    
    
    
    
     
    
    0O1BVTFE
    

    View Slide

74. 
    
    
    
    
    
     
    
    0O1BVTFE
    #MPDL
    

    View Slide

75. 
    
    
    
    
    
     
    
    0O%FTUSPZFE
    

    View Slide

76. 
    
    
    
    
    
     
    
    0O%FTUSPZFE
    

    View Slide

77. -JWF%BUB
    ٥0CTFSWBCMFEBUBIPMEFS
    ٥-JGFDZDMF"XBSF
    ٥/PMFBL
    

    View Slide

78. 7JFX.PEFM
    

    View Slide

79. 
    
    
    
    

    View Slide

80. 
    
    
    
    
    

    View Slide

81. 
    
    
    
    
    
    

    View Slide

82. 
    
    
    
    
    
    
    

    View Slide

83. 
    
    
    
    
    
    

    View Slide

84. 
    
    
    
    
    
    
    

    View Slide

85. 
    
    
    
    
    
    
    
    

    View Slide

86. 
    
    
    
    
    

    View Slide

87. 
    
    
    
    
    
    

    View Slide

88. 
    
    
    
    
    
    

    View Slide

89. 
    /PO$POHVSBUJPO*OTUBODF
    

    View Slide

90. 
    
    
    
    
    
    

    View Slide

91. 
    
    
    
    
    
    
    

    View Slide

92. 
    
    
    
    
    
    
    

    View Slide

93. 
    
    
    
    
    
    
    

    View Slide

94. 7JFX.PEFM
    ٥%BUBIPMEFS
    ٥4VSWJWFTDPOHVSBUJPODIBOHFT
    ٥/FWFSSFGFSFODFT$POUFYU
    

    View Slide

95. )PXUPVTF
    

    View Slide

96. TUFQ
    "EEDPNQPOFOUT
    

    View Slide

97. dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation"org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    implementation 'androidx.appcompat:appcompat:1.0.0-rc02'
    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
    }
    -JGFDZDMFT
    

    View Slide

98. dependencies {
    …
    def lifecycle_version = "2.0.0-rc01"
    implementation "androidx.lifecycle:lifecycle-extensions:$lifecycle_version"
    }
    -JWF%BUB7JFX.PEFM
    

    View Slide

99. apply plugin : 'kotlin-kapt'
    dependencies {
    …
    def lifecycle_version = "2.0.0-rc01"
    implementation "androidx.lifecycle:lifecycle-extensions:$lifecycle_version"
    kapt "androidx.lifecycle:lifecycle-compiler:$lifecycle_version"
    }
    -JGFDZDMF0CTFSWFS
    

    View Slide

100. dependencies {
     ...
     implementation "org.jetbrains.kotlinx:kotlinx-coroutines-core:0.22.5"
     implementation "org.jetbrains.kotlinx:kotlinx-coroutines-android:0.22.5"
     implementation "com.squareup.okhttp3:okhttp:3.10.0"
     implementation "com.squareup.okhttp3:logging-interceptor:3.10.0"
     implementation "com.squareup.retrofit2:retrofit:2.4.0"
     implementation "com.squareup.retrofit2:converter-gson:2.4.0"
     implementation 'com.jakewharton.retrofit:retrofit2-kotlin-coroutines-experimental-adapter:1.0.0'
     implementation 'com.google.code.gson:gson:2.8.2'
     implementation 'androidx.recyclerview:recyclerview:1.0.0-rc02'
     }
     kotlin {
     experimental {
     coroutines "enable"
     }
     }
     

     View Slide

101. TUFQ
     $SFBUFDPNQPOFOUT
     

     View Slide

102. class YourViewModel : ViewModel() {
     }
     

     View Slide

103. class YourViewModel : ViewModel() {
     }
     

     View Slide

104. class YourViewModel : ViewModel() {
     private val _repos = MutableLiveData>()
     }
     

     View Slide

105. class YourViewModel : ViewModel() {
     private val _repos = MutableLiveData>()
     }
     

     View Slide

106. class YourViewModel : ViewModel() {
     private val _repos = MutableLiveData>()
     }
     

     View Slide

107. class YourViewModel : ViewModel() {
     private val _repos = MutableLiveData>()
     val repositories : LiveData>
     }
     

     View Slide

108. class YourViewModel : ViewModel() {
     private val _repos = MutableLiveData>()
     val repositories : LiveData>
     get() {
     if (_repos.value == null) {
     val repos = github.repositories()
     _repos.postValue(repos)
     }
     return _repos
     }
     }
     

     View Slide

109. class YourViewModel : ViewModel() {
     private val _repos = MutableLiveData>()
     val repositories : LiveData>
     get() {
     if (_repos.value == null) {
     val repos = github.repositories()
     _repos.postValue(repos)
     }
     return _repos
     }
     }
     

     View Slide

110. class YourViewModel : ViewModel() {
     private val _repos = MutableLiveData>()
     val repositories : LiveData>
     get() {
     if (_repos.value == null) {
     val repos = github.repositories()
     _repos.postValue(repos)
     }
     return _repos
     }
     }
     

     View Slide

111. class YourViewModel : ViewModel() {
     private val _repos = MutableLiveData>()
     val repositories : LiveData>
     get() {
     if (_repos.value == null) {
     val repos = github.repositories()
     _repos.postValue(repos)
     }
     return _repos
     }
     }
     

     View Slide

112. class YourViewModel : ViewModel() {
     private val _repos = MutableLiveData>()
     val repositories : LiveData>
     get() {
     if (_repos.value == null) {
     // Coroutine way
     launch(CommonPool) {
     val repos = github.repositories().await()
     _repos.postValue(repos)
     }
     }
     return _repos
     }
     }
     

     View Slide

113. class YourViewModel : ViewModel() {
     private val _repos = MutableLiveData>()
     val repositories : LiveData>
     get() {
     if (_repos.value == null) {
     // Rx way
     github.repositories()
     .observeOn(AndroidSchedulers.mainThread())
     .subscribeOn(Schedulers.io())
     .subscribe { repositories.postValue(it) }
     }
     return _repos
     }
     }
     

     View Slide

114. TUFQ
     &OKPZZPVSDPNQPOFOUT
     

     View Slide

115. class MainActivity : AppCompatActivity() {
     override fun onCreate(savedInstanceState: Bundle?) {
     ...
     val viewModel = ViewModelProviders.of(this)[YourViewModel::class.java]
     }
     }
     

     View Slide

116. class MainActivity : AppCompatActivity() {
     override fun onCreate(savedInstanceState: Bundle?) {
     ...
     val viewModel = ViewModelProviders.of(this)[YourViewModel::class.java]
     viewModel.repositories.observe(this, Observer { // update Views })
     }
     }
     

     View Slide

117. $PODMVTJPO
     

     View Slide

118. -JGFDZDMF.BOBHFNFOU
     -JGFDZDMFDPNQPOFOUT
     JTIBSE
     DBODBVTFQSPCMFNT
     IBTTJNQMFEFTJHO
     :PVDBOVTFFBTJMZ
     

     View Slide

119. )JSPZVLJ.PSJ
     !NPSJESPJE
     5IBOLZPV
     

     View Slide