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
2. Slide URL • https://goo.gl/zwxdyy
3. About Me • Fumihiko Shiroyama • Android App Developer • Nikkei Inc. • https://github.com/srym • https://twitter.com/fushiroyama
4. Agenda • Face up to the reality of crash! • Take the first step for Unit Testing • Make biggest gains without Unit Testing
5. The Fact Your App is Crashing
6. The Fact Your App is Crashing • 99% Crash Free? Good! • DAU 30000
7. The Fact Your App is Crashing • 99% Crash Free? Good! • DAU 30000 
   $SBTIFT
8. The Fact Your App is Crashing • 99% Crash Free? Good! • DAU 30000 • 99.9% Crash Free? Great!!
9. The Fact Your App is Crashing • 99% Crash Free? Good! • DAU 30000 • 99.9% Crash Free? Great!! 4UJMM
   
   $SBTIFT
10. Keep Going!!!
12. Fabric • Crashlytics • Beta • Answers • Acquired by Google
13. "4
    1MVHJO
14. Crashlytics • Automatically collects crash info • No need for uploading obfuscation mappings • Crashlytics#logException(e) for non-fatal
15. Crashlytics private void logUser() { // info about user Crashlytics.setUserIdentifier("12345"); Crashlytics.setUserEmail("user@fabric.io"); Crashlytics.setUserName("Test User"); }
16. Crashlytics private void logUser() { // info about user Crashlytics.setUserIdentifier("12345"); Crashlytics.setUserEmail("user@fabric.io"); Crashlytics.setUserName("Test User"); }
17. Firebase Crash Reporting • Similar to Crashlytics
18. "4
    1MVHJO
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
20. Crash Reporting Normal Stack Trace
21. Crash Reporting Device Info
22. Crash Reporting Contextual History
23. Crash Reporting Contextual History $00- &WFOU
    -PH
24. Integration
26. Timber dependencies { compile 'com.jakewharton.timber:timber:4.5.1' }
27. Timber dependencies { compile 'com.jakewharton.timber:timber:4.5.1' } #FUUFS
    -PHE
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); } } }
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); } } }
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); } } }
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
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()); } } }
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()); } } }
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()); } } }
35. Timber Timber.d("log message"); // or Timber.e(error, error.getMessage());
36. Take the first step for Unit Testing
37. Why can't you write test?
38. Typical Case
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); } }); }
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); } }); }
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); } }); }
42. Typical Case private User fetchUser(long userId) { return apiClient.findUserById(userId); }
43. Typical Case private User fetchUser(long userId) { return apiClient.findUserById(userId); } pFME
    BDDFTT
44. How do I test MyActivity#fetchUser ?
45. That's impossible
46. Make it testable private User fetchUser(long userId) { return apiClient.findUserById(userId); }
47. Make it testable private User fetchUser(ApiClient apiClient, long userId) { return apiClient.findUserById(userId); }
48. private User fetchUser(ApiClient apiClient, long userId) { return apiClient.findUserById(userId); } 3FNPWFE
    pFME
    BDDFTT Make it testable
49. private User fetchUser(ApiClient apiClient, long userId) { return apiClient.findUserById(userId); } Make it testable
50. public class UserFetcher { private User fetchUser(ApiClient apiClient, long userId) { return apiClient.findUserById(userId); } } Make it testable
51. public class UserFetcher { public User fetchUser(ApiClient apiClient, long userId) { return apiClient.findUserById(userId); } } Make it testable
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
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
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
55. Anything else?
56. Problem is Activity
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); } }); }
58. Let's split this into parts!
59. MVP
60. What is MVP • Model - View - Presenter • View…Activity (Fragment) • Model…Business Logic (e.g. fetching data) • Presenter…Bridge between V & M
61. Introduce MVP public interface UserContract { public interface View { void showUser(User user); void showError(Exception error); } public interface Interaction { void clickButton(long userId); } }
62. Introduce MVP public interface UserContract { public interface View { void showUser(User user); void showError(Exception error); } public interface Interaction { void clickButton(long userId); } } $POUSBDU
    CFUXFFO
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    1SFTFOUFS
63. Introduce MVP public interface UserContract { public interface View { void showUser(User user); void showError(Exception error); } public interface Interaction { void clickButton(long userId); } }
64. Introduce MVP public interface UserContract { public interface View { void showUser(User user); void showError(Exception error); } public interface Interaction { void clickButton(long userId); } } $BMMCBDL
    GSPN
    1SFTFOUFS
65. Introduce MVP public interface UserContract { public interface View { void showUser(User user); void showError(Exception error); } public interface Interaction { void clickButton(long userId); } }
66. Introduce MVP public interface UserContract { public interface View { void showUser(User user); void showError(Exception error); } public interface Interaction { void clickButton(long userId); } } &WFOU
    GSPN
    6*
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) { } }
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) { } }
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) { } }
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); } }); }
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); } }); }
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); } }); }
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) {} }
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) {} }
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()); } }
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()); } }
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()); } }
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()); } }
79. Result • Now objects' responsibilities are clearer • Dependency is provided at constructor • Thus testable!
80. Make biggest gains without Unit Testing
81. It turned out...
82. Quite a few crashes were caused by...
83. IllegalStateException java.lang.IllegalStateException: Can not perform this action after onSaveInstanceState
84. IllegalStateException java.lang.IllegalStateException: Can not perform this action after onSaveInstanceState 'SBHNFOU5SBOTBDUJPODPNNJU
85. FragmentTransaction • FragmentTransaction#commit • DialogFragment#show
86. FragmentTransaction public void show(FragmentManager manager, String tag) { mDismissed = false; mShownByMe = true; FragmentTransaction ft = manager.beginTransaction(); ft.add(this, tag); ft.commit(); }
87. FragmentTransaction public void show(FragmentManager manager, String tag) { mDismissed = false; mShownByMe = true; FragmentTransaction ft = manager.beginTransaction(); ft.add(this, tag); ft.commit(); }
88. Don't commit after... • AsyncTask#onPostExecute • LoaderCallbacks#onLoadFinished • Actually ANY KINDS OF ASYNC CALLBACKS are not safe
89. RxLifecycle?
90. RxLifecycle • RxLifecycle IS GREAT!! • Not all programmers, nor projects always need this. • Vulture is for you!
91. Vulture • https://github.com/srym/vulture • Handles async callback safely • Based on PauseHandler* picture from wikimedia.org * https://goo.gl/g6w3CS
92. Vulture void fetchAsynchronously() { /* do heavy asynchronous task here */ doCallback("finished!"); } void doCallback(@NonNull String message) { FinishDialog.newInstance().show( getSupportFragmentManager(), "TAG"); }
93. Vulture void fetchAsynchronously() { /* do heavy asynchronous task here */ doCallback("finished!"); } void doCallback(@NonNull String message) { FinishDialog.newInstance().show( getSupportFragmentManager(), "TAG"); }
94. Vulture void fetchAsynchronously() { /* do heavy asynchronous task here */ doCallback("finished!"); } void doCallback(@NonNull String message) { FinishDialog.newInstance().show( getSupportFragmentManager(), "TAG"); }
95. Vulture void fetchAsynchronously() { /* do heavy asynchronous task here */ doCallback("finished!"); } void doCallback(@NonNull String message) { FinishDialog.newInstance().show( getSupportFragmentManager(), "TAG"); } 6OTBGF
96. Vulture @ObserveLifecycle public class YourActivity extends AppCompatActivity { void fetchAsynchronously() { SafeMainActivity.doCallbackSafely("finished!"); } @SafeCallback void doCallback(@NonNull String message) { FinishDialog.newInstance().show( getSupportFragmentManager(), "TAG"); } }
97. Vulture @ObserveLifecycle public class YourActivity extends AppCompatActivity { void fetchAsynchronously() { SafeMainActivity.doCallbackSafely("finished!"); } @SafeCallback void doCallback(@NonNull String message) { FinishDialog.newInstance().show( getSupportFragmentManager(), "TAG"); } }
98. Vulture @ObserveLifecycle public class YourActivity extends AppCompatActivity { void fetchAsynchronously() { SafeMainActivity.doCallbackSafely("finished!"); } @SafeCallback void doCallback(@NonNull String message) { FinishDialog.newInstance().show( getSupportFragmentManager(), "TAG"); } }
99. Vulture @Override protected void onResume() { super.onResume(); SafeMainActivity.register(this); } @Override protected void onPause() { SafeMainActivity.unregister(); super.onPause(); }
100. Vulture @Override protected void onResume() { super.onResume(); SafeMainActivity.register(this); } @Override protected void onPause() { SafeMainActivity.unregister(); super.onPause(); }
101. Supported Types • Primitive types and its boxed types • String, Bundle, Parcelable, Serializable • ParcelableArray • ParcelableArrayList
102. Vulture • Currently Beta release • I need your feedbacks! picture from wikimedia.org
103. Thank You!
104. Special Thanks • Illustrations by ͍Β͢ͱ΍ • http://www.irasutoya.com/ • Thank you so much!!! • https://www.wikimedia.org/ • All the audiences! Thank you!