Journey to 99% Crash Free

DroidKaigi 2017 Day 2 (17:10 - 17:40 Room 1)
「テスト0から目指すクラッシュフリー率99%」

Transcript

1. Journey to
   99% Crash Free
   Fumihiko Shiroyama
   

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2. Slide URL
   • https://goo.gl/zwxdyy
   

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3. About Me
   • Fumihiko Shiroyama
   • Android App Developer
   • Nikkei Inc.
   • https://github.com/srym
   • https://twitter.com/fushiroyama
   

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4. Agenda
   • Face up to the reality of crash!
   • Take the first step for Unit Testing
   • Make biggest gains without Unit Testing
   

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5. The Fact Your App is Crashing
   

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6. The Fact Your App is Crashing
   • 99% Crash Free? Good!
   • DAU 30000
   

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7. The Fact Your App is Crashing
   • 99% Crash Free? Good!
   • DAU 30000
   $SBTIFT
   

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8. The Fact Your App is Crashing
   • 99% Crash Free? Good!
   • DAU 30000
   • 99.9% Crash Free? Great!!
   

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9. The Fact Your App is Crashing
   • 99% Crash Free? Good!
   • DAU 30000
   • 99.9% Crash Free? Great!!
   4UJMM$SBTIFT
   

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10. Keep Going!!!
    

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12. Fabric
    • Crashlytics
    • Beta
    • Answers
    • Acquired by Google
    

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13. "41MVHJO
    

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14. Crashlytics
    • Automatically collects crash info
    • No need for uploading obfuscation
    mappings
    • Crashlytics#logException(e) for non-fatal
    

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15. Crashlytics
    private void logUser() {
    // info about user
    Crashlytics.setUserIdentifier("12345");
    Crashlytics.setUserEmail("user@fabric.io");
    Crashlytics.setUserName("Test User");
    }
    

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16. Crashlytics
    private void logUser() {
    // info about user
    Crashlytics.setUserIdentifier("12345");
    Crashlytics.setUserEmail("user@fabric.io");
    Crashlytics.setUserName("Test User");
    }
    

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17. Firebase Crash Reporting
    • Similar to Crashlytics
    

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18. "41MVHJO
    

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19. Crash Reporting
    • Automatically collects crash info as well
    • Need for uploading obfuscation mappings
    (there is a helper gradle plugin)
    • FirebaseCrash.report(e) for non-fatal
    

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20. Crash Reporting
    Normal Stack Trace
    

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21. Crash Reporting
    Device Info
    

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22. Crash Reporting
    Contextual History
    

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23. Crash Reporting
    Contextual History
    $00-
    &WFOU
    -PH
    

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24. Integration
    

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26. Timber
    dependencies {
    compile 'com.jakewharton.timber:timber:4.5.1'
    }
    

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27. Timber
    dependencies {
    compile 'com.jakewharton.timber:timber:4.5.1'
    }
    #FUUFS-PHE
    

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28. Timber
    public class CrashReportingTree extends Timber.Tree {
    @Override
    protected void log(int priority, String tag,
    String message, Throwable t) {
    if (priority == Log.VERBOSE ||
    priority == Log.DEBUG ||
    priority == Log.INFO) {
    return;
    }
    if (t != null) {
    Crashlytics.logException(t);
    FirebaseCrash.report(t);
    }
    }
    }
    

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29. Timber
    public class CrashReportingTree extends Timber.Tree {
    @Override
    protected void log(int priority, String tag,
    String message, Throwable t) {
    if (priority == Log.VERBOSE ||
    priority == Log.DEBUG ||
    priority == Log.INFO) {
    return;
    }
    if (t != null) {
    Crashlytics.logException(t);
    FirebaseCrash.report(t);
    }
    }
    }
    

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30. Timber
    public class CrashReportingTree extends Timber.Tree {
    @Override
    protected void log(int priority, String tag,
    String message, Throwable t) {
    if (priority == Log.VERBOSE ||
    priority == Log.DEBUG ||
    priority == Log.INFO) {
    return;
    }
    if (t != null) {
    Crashlytics.logException(t);
    FirebaseCrash.report(t);
    }
    }
    }
    

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31. Timber
    public class CrashReportingTree extends Timber.Tree {
    @Override
    protected void log(int priority, String tag,
    String message, Throwable t) {
    if (priority == Log.VERBOSE ||
    priority == Log.DEBUG ||
    priority == Log.INFO) {
    return;
    }
    if (t != null) {
    Crashlytics.logException(t);
    FirebaseCrash.report(t);
    }
    }
    }
    /PO'BUBM
    

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32. Timber
    public class MyApplication extends Application {
    @Override
    public void onCreate() {
    super.onCreate();
    initTimber();
    }
    private void initTimber() {
    if (BuildConfig.DEBUG) {
    Timber.plant(new Timber.DebugTree());
    } else {
    Timber.plant(new CrashReportingTree());
    }
    }
    }
    

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33. Timber
    public class MyApplication extends Application {
    @Override
    public void onCreate() {
    super.onCreate();
    initTimber();
    }
    private void initTimber() {
    if (BuildConfig.DEBUG) {
    Timber.plant(new Timber.DebugTree());
    } else {
    Timber.plant(new CrashReportingTree());
    }
    }
    }
    

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34. Timber
    public class MyApplication extends Application {
    @Override
    public void onCreate() {
    super.onCreate();
    initTimber();
    }
    private void initTimber() {
    if (BuildConfig.DEBUG) {
    Timber.plant(new Timber.DebugTree());
    } else {
    Timber.plant(new CrashReportingTree());
    }
    }
    }
    

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35. Timber
    Timber.d("log message");
    // or
    Timber.e(error, error.getMessage());
    

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36. Take the first step for Unit Testing
    

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37. Why can't you write test?
    

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38. Typical Case
    

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39. Fat Activity
    @Override
    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    button.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
    User user = fetchUser(userId);
    processUser(user);
    }
    });
    }
    

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40. Fat Activity
    @Override
    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    button.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
    User user = fetchUser(userId);
    processUser(user);
    }
    });
    }
    

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41. Fat Activity
    @Override
    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    button.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
    User user = fetchUser(userId);
    processUser(user);
    }
    });
    }
    

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42. Typical Case
    private User fetchUser(long userId) {
    return apiClient.findUserById(userId);
    }
    

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43. Typical Case
    private User fetchUser(long userId) {
    return apiClient.findUserById(userId);
    }
    pFMEBDDFTT
    

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44. How do I test MyActivity#fetchUser ?
    

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45. That's impossible
    

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46. Make it testable
    private User fetchUser(long userId) {
    return apiClient.findUserById(userId);
    }
    

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47. Make it testable
    private User fetchUser(ApiClient apiClient,
    long userId) {
    return apiClient.findUserById(userId);
    }
    

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48. private User fetchUser(ApiClient apiClient,
    long userId) {
    return apiClient.findUserById(userId);
    }
    3FNPWFE
    pFMEBDDFTT
    Make it testable
    

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49. private User fetchUser(ApiClient apiClient,
    long userId) {
    return apiClient.findUserById(userId);
    }
    Make it testable
    

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50. public class UserFetcher {
    private User fetchUser(ApiClient apiClient,
    long userId) {
    return apiClient.findUserById(userId);
    }
    }
    Make it testable
    

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51. public class UserFetcher {
    public User fetchUser(ApiClient apiClient,
    long userId) {
    return apiClient.findUserById(userId);
    }
    }
    Make it testable
    

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52. public class UserFetcher {
    private final ApiClient apiClient;
    public UserFetcher(ApiClient apiClient) {
    this.apiClient = apiClient;
    }
    public User fetchUser(long userId) {
    return apiClient.findUserById(userId);
    }
    }
    Make it testable
    

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53. public class UserFetcher {
    private final ApiClient apiClient;
    public UserFetcher(ApiClient apiClient) {
    this.apiClient = apiClient;
    }
    public User fetchUser(long userId) {
    return apiClient.findUserById(userId);
    }
    }
    Make it testable
    

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54. Make it testable
    • This is so-called Dependency Injection
    • DI can be done without any libraries!
    • You can use DI library at any time though
    

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55. Anything else?
    

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56. Problem is Activity
    

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57. Everything is in Activity
    @Override
    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    button.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
    User user = fetchUser(userId);
    processUser(user);
    }
    });
    }
    

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58. Let's split this into parts!
    

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59. MVP
    

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60. What is MVP
    • Model - View - Presenter
    • View…Activity (Fragment)
    • Model…Business Logic (e.g. fetching data)
    • Presenter…Bridge between V & M
    

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61. Introduce MVP
    public interface UserContract {
    public interface View {
    void showUser(User user);
    void showError(Exception error);
    }
    public interface Interaction {
    void clickButton(long userId);
    }
    }
    

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62. Introduce MVP
    public interface UserContract {
    public interface View {
    void showUser(User user);
    void showError(Exception error);
    }
    public interface Interaction {
    void clickButton(long userId);
    }
    }
    $POUSBDUCFUXFFO
    7JFXBOE1SFTFOUFS
    

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63. Introduce MVP
    public interface UserContract {
    public interface View {
    void showUser(User user);
    void showError(Exception error);
    }
    public interface Interaction {
    void clickButton(long userId);
    }
    }
    

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64. Introduce MVP
    public interface UserContract {
    public interface View {
    void showUser(User user);
    void showError(Exception error);
    }
    public interface Interaction {
    void clickButton(long userId);
    }
    }
    $BMMCBDLGSPN
    1SFTFOUFS
    

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65. Introduce MVP
    public interface UserContract {
    public interface View {
    void showUser(User user);
    void showError(Exception error);
    }
    public interface Interaction {
    void clickButton(long userId);
    }
    }
    

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66. Introduce MVP
    public interface UserContract {
    public interface View {
    void showUser(User user);
    void showError(Exception error);
    }
    public interface Interaction {
    void clickButton(long userId);
    }
    }
    &WFOUGSPN
    6*
    

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67. Introduce MVP
    public class UserPresenter implements UserContract.Interaction {
    private final UserContract.View view;
    private final UserFetcher userFetcher;
    public UserPresenter(UserContract.View view,
    UserFetcher userFetcher) {
    this.view = view;
    this.userFetcher = userFetcher;
    }
    @Override
    public void clickButton(long userId) {
    }
    }
    

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68. Introduce MVP
    public class UserPresenter implements UserContract.Interaction {
    private final UserContract.View view;
    private final UserFetcher userFetcher;
    public UserPresenter(UserContract.View view,
    UserFetcher userFetcher) {
    this.view = view;
    this.userFetcher = userFetcher;
    }
    @Override
    public void clickButton(long userId) {
    }
    }
    

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69. Introduce MVP
    public class UserPresenter implements UserContract.Interaction {
    private final UserContract.View view;
    private final UserFetcher userFetcher;
    public UserPresenter(UserContract.View view,
    UserFetcher userFetcher) {
    this.view = view;
    this.userFetcher = userFetcher;
    }
    @Override
    public void clickButton(long userId) {
    }
    }
    

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70. Introduce MVP
    @Override
    public void clickButton(long userId) {
    userFetcher.findUserAsync(userId,
    new UserFetcher.OnSuccessCallback() {
    @Override
    public void onSuccess(User user) {
    view.showUser(user);
    }
    },
    new UserFetcher.OnFailureCallback() {
    @Override
    public void onFailure(Exception e) {
    view.showError(e);
    }
    });
    }
    

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71. Introduce MVP
    @Override
    public void clickButton(long userId) {
    userFetcher.findUserAsync(userId,
    new UserFetcher.OnSuccessCallback() {
    @Override
    public void onSuccess(User user) {
    view.showUser(user);
    }
    },
    new UserFetcher.OnFailureCallback() {
    @Override
    public void onFailure(Exception e) {
    view.showError(e);
    }
    });
    }
    

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72. Introduce MVP
    @Override
    public void clickButton(long userId) {
    userFetcher.findUserAsync(userId,
    new UserFetcher.OnSuccessCallback() {
    @Override
    public void onSuccess(User user) {
    view.showUser(user);
    }
    },
    new UserFetcher.OnFailureCallback() {
    @Override
    public void onFailure(Exception e) {
    view.showError(e);
    }
    });
    }
    

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73. Introduce MVP
    public class MyActivity extends BaseActivity
    implements UserContract.View {
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    }
    @Override
    public void showUser(User user) {}
    @Override
    public void showError(Exception error) {}
    }
    

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74. Introduce MVP
    public class MyActivity extends BaseActivity
    implements UserContract.View {
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    }
    @Override
    public void showUser(User user) {}
    @Override
    public void showError(Exception error) {}
    }
    

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75. Introduce MVP
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
    final UserPresenter presenter = new UserPresenter(this, userFetcher);
    button.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
    presenter.clickButton(userId);
    }
    });
    }
    @Override
    public void showUser(User user) { toastMessage(user.getName()); }
    @Override
    public void showError(Exception e) { toastMessage(e()); }
    }
    

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76. Introduce MVP
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
    final UserPresenter presenter = new UserPresenter(this, userFetcher);
    button.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
    presenter.clickButton(userId);
    }
    });
    }
    @Override
    public void showUser(User user) { toastMessage(user.getName()); }
    @Override
    public void showError(Exception e) { toastMessage(e()); }
    }
    

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77. Introduce MVP
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
    final UserPresenter presenter = new UserPresenter(this, userFetcher);
    button.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
    presenter.clickButton(userId);
    }
    });
    }
    @Override
    public void showUser(User user) { toastMessage(user.getName()); }
    @Override
    public void showError(Exception e) { toastMessage(e()); }
    }
    

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78. Introduce MVP
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
    final UserPresenter presenter = new UserPresenter(this, userFetcher);
    button.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
    presenter.clickButton(userId);
    }
    });
    }
    @Override
    public void showUser(User user) { toastMessage(user.getName()); }
    @Override
    public void showError(Exception e) { toastMessage(e()); }
    }
    

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79. Result
    • Now objects' responsibilities are clearer
    • Dependency is provided at constructor
    • Thus testable!
    

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80. Make biggest gains
    without Unit Testing
    

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81. It turned out...
    

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82. Quite a few crashes
    were caused by...
    

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83. IllegalStateException
    java.lang.IllegalStateException:
    Can not perform this action after onSaveInstanceState
    

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84. IllegalStateException
    java.lang.IllegalStateException:
    Can not perform this action after onSaveInstanceState
    'SBHNFOU5SBOTBDUJPODPNNJU
    

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85. FragmentTransaction
    • FragmentTransaction#commit
    • DialogFragment#show
    

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86. FragmentTransaction
    public void show(FragmentManager manager, String tag) {
    mDismissed = false;
    mShownByMe = true;
    FragmentTransaction ft = manager.beginTransaction();
    ft.add(this, tag);
    ft.commit();
    }
    

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87. FragmentTransaction
    public void show(FragmentManager manager, String tag) {
    mDismissed = false;
    mShownByMe = true;
    FragmentTransaction ft = manager.beginTransaction();
    ft.add(this, tag);
    ft.commit();
    }
    

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88. Don't commit after...
    • AsyncTask#onPostExecute
    • LoaderCallbacks#onLoadFinished
    • Actually ANY KINDS OF ASYNC CALLBACKS
    are not safe
    

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89. RxLifecycle?
    

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90. RxLifecycle
    • RxLifecycle IS GREAT!!
    • Not all programmers, nor projects always
    need this.
    • Vulture is for you!
    

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91. Vulture
    • https://github.com/srym/vulture
    • Handles async callback safely
    • Based on PauseHandler*
    picture from wikimedia.org
    * https://goo.gl/g6w3CS
    

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92. Vulture
    void fetchAsynchronously() {
    /* do heavy asynchronous task here */
    doCallback("finished!");
    }
    void doCallback(@NonNull String message) {
    FinishDialog.newInstance().show(
    getSupportFragmentManager(), "TAG");
    }
    

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93. Vulture
    void fetchAsynchronously() {
    /* do heavy asynchronous task here */
    doCallback("finished!");
    }
    void doCallback(@NonNull String message) {
    FinishDialog.newInstance().show(
    getSupportFragmentManager(), "TAG");
    }
    

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94. Vulture
    void fetchAsynchronously() {
    /* do heavy asynchronous task here */
    doCallback("finished!");
    }
    void doCallback(@NonNull String message) {
    FinishDialog.newInstance().show(
    getSupportFragmentManager(), "TAG");
    }
    

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95. Vulture
    void fetchAsynchronously() {
    /* do heavy asynchronous task here */
    doCallback("finished!");
    }
    void doCallback(@NonNull String message) {
    FinishDialog.newInstance().show(
    getSupportFragmentManager(), "TAG");
    }
    6OTBGF
    

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96. Vulture
    @ObserveLifecycle
    public class YourActivity extends AppCompatActivity {
    void fetchAsynchronously() {
    SafeMainActivity.doCallbackSafely("finished!");
    }
    @SafeCallback
    void doCallback(@NonNull String message) {
    FinishDialog.newInstance().show(
    getSupportFragmentManager(), "TAG");
    }
    }
    

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97. Vulture
    @ObserveLifecycle
    public class YourActivity extends AppCompatActivity {
    void fetchAsynchronously() {
    SafeMainActivity.doCallbackSafely("finished!");
    }
    @SafeCallback
    void doCallback(@NonNull String message) {
    FinishDialog.newInstance().show(
    getSupportFragmentManager(), "TAG");
    }
    }
    

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98. Vulture
    @ObserveLifecycle
    public class YourActivity extends AppCompatActivity {
    void fetchAsynchronously() {
    SafeMainActivity.doCallbackSafely("finished!");
    }
    @SafeCallback
    void doCallback(@NonNull String message) {
    FinishDialog.newInstance().show(
    getSupportFragmentManager(), "TAG");
    }
    }
    

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99. Vulture
    @Override
    protected void onResume() {
    super.onResume();
    SafeMainActivity.register(this);
    }
    @Override
    protected void onPause() {
    SafeMainActivity.unregister();
    super.onPause();
    }
    

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100. Vulture
     @Override
     protected void onResume() {
     super.onResume();
     SafeMainActivity.register(this);
     }
     @Override
     protected void onPause() {
     SafeMainActivity.unregister();
     super.onPause();
     }
     

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101. Supported Types
     • Primitive types and its boxed types
     • String, Bundle, Parcelable, Serializable
     • ParcelableArray
     • ParcelableArrayList
     

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102. Vulture
     • Currently Beta release
     • I need your feedbacks!
     picture from wikimedia.org
     

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103. Thank You!
     

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104. Special Thanks
     • Illustrations by ͍Β͢ͱ΍
     • http://www.irasutoya.com/
     • Thank you so much!!!
     • https://www.wikimedia.org/
     • All the audiences! Thank you!
     

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