Things That Suck About Android Development

Developing for Android can be an emotional rollercoaster. We alternate from pure childlike joy when new tools & APIs are announced to feelings of impending doom when we have to do anything involving camera support or ContentProviders. Talk to anyone who has been working with Android for long and the conversation inevitably turns to “war stories”, recounting hard battles fought and won (or at least survived) while building apps for our favorite mobile platform.

Are you new to Android development? If so, this session will show you where the dragons are so you can avoid many of the common pitfalls. If you’re a veteran, you’ll certainly recognize some of these frustrations while hopefully learning about some others you’ve been fortunate enough to elude.

From the Java language and development tools to frameworks/APIs and the Play Store, nothing is sacred.

Transcript

1. Things That Suck About
   Android Development
   by Andy Dyer
   #mdevcon
   

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2. #mdevcon
   

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3. "Everything's amazing
   and nobody's happy"
   — Louis CK
   #mdevcon
   

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4. #mdevcon
   

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5. #mdevcon
   

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6. Java 6
   No Java 8 due to Oracle's
   beef with Google*
   #mdevcon
   

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7. Java 6 Lambdas with Retrolambda
   button.setOnClickListener(new View.OnClickListener() {
   @Override
   public void onClick(View v) {
   doSomething(v);
   }
   });
   button.setOnClickListener(v -> doSomething(v));
   #mdevcon
   

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8. Java 6 Streams with RxJava
   Map positionsMap = getPositionsMap();
   Observable.from(getPayrollHours())
   .filter(payrollHour -> payrollHour.getUserId() == userId)
   .groupBy(payrollHour -> payrollHour.getPositionId())
   .flatMap(group -> {
   Position position = positionsMap.get(group.getKey());
   return group.toList().map(hours ->
   new PositionSummary(position, hours));
   })
   .toList()
   .toBlocking()
   .firstOrDefault(new ArrayList<>());
   #mdevcon
   

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9. #mdevcon
   

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10. Tools: Weird Stuff
    → Clean Project vs Rebuild Project
    → File > New > Fragment/Activity boilerplate
    → Problems using Git SHA in APK name
    #mdevcon
    

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11. Tools: Pixel Pushing
    → 10 px = ? dp
    → XXXXXHDPI
    → Custom fonts
    → Bottom tab bars, carets on list items, etc.
    #mdevcon
    

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12. Build times
    + slow emulator
    = long feedback loop
    #mdevcon
    

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13. Shorten the
    Feedback Loop
    → New emulator & Instant Run
    → Genymotion emulator
    → Gradle offline mode
    → Launch activity or skeleton app
    → Automated Testing > Manual
    Testing
    #mdevcon
    

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14. Tools: Testing
    → Default Android architecture is not easily testable
    → Two different test flavors - androidTest for
    instrumentation tests and test for unit tests
    → Flaky emulator performance when running more
    than a few instrumentation tests
    #mdevcon
    

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15. Testing Tips
    → Separate activities/fragments from business logic
    with a design pattern like Model-View-Presenter
    → Favor unit tests over instrumentation tests. They
    run much faster.
    → Turn off animations in Settings > Developer
    Options to fix emulator flakiness.
    → It will be hard at first. Power through it!
    #mdevcon
    

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16. MVP: Model
    public class Shift {
    private long id;
    private long employeeId;
    private DateTime startTime;
    private DateTime endTime;
    // ...
    // Constructor
    // Getters
    }
    #mdevcon
    

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17. MVP: View Interface
    public interface ShiftsView {
    void bindShifts(List shifts);
    void toggleProgressVisibility(boolean visible);
    void showError(Throwable throwable);
    Observable.Transformer bindToLifecycle();
    }
    #mdevcon
    

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18. MVP: View Implementation
    public class ShiftsFragment extends RxFragment implements ShiftsView {
    @Override
    public void onViewCreated(View view, Bundle savedInstanceState) {
    ShiftsPresenter presenter = new ShiftsPresenterImpl(this, api, schedulerTransformer);
    presenter.loadShifts(getArguments().getLong(ARG_SHIFT_ID));
    }
    @Override
    public void bindShifts(List shifts) { }
    @Override
    public void toggleProgressVisibility(boolean visible) { }
    @Override
    public void showError(Throwable throwable) { }
    }
    #mdevcon
    

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19. MVP: Presenter Interface
    public interface ShiftsPresenter {
    void loadShifts(DateTime startTime, DateTime endTime);
    }
    #mdevcon
    

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20. MVP: Presenter Implementation
    public class ShiftsPresenterImpl implements ShiftsPresenter {
    public ShiftsPresenterImpl(ShiftsView view, MyRetrofitApi api,
    Observable.Transformer schedulerTransformer) {
    // Set fields
    }
    @Override
    public void loadShifts(DateTime startTime, DateTime endTime) {
    view.toggleProgressVisibility(true);
    api.listShifts(startTime, endTime)
    .doOnNext(response -> view.toggleProgressVisibility(false))
    .doOnError(response -> view.toggleProgressVisibility(false))
    .compose(schedulerTransformer)
    .compose(view.bindToLifecycle())
    .subscribe(shifts -> view.bindShifts(shifts), throwable -> view.showError(throwable));
    }
    }
    #mdevcon
    

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21. MVP: Presenter Testing
    public class ShiftsPresenterTest {
    @Mock private ShiftsView shiftsView;
    @Mock private MyRetrofitApi api;
    private ShiftsPresenter presenter;
    @Before
    public void setUp() throws Exception {
    MockitoAnnotations.initMocks(this);
    when(shiftsView.bindToLifecycle())
    .thenReturn(new EmptyLifecycleTransformer<>());
    presenter = new ShiftsPresenter(shiftsView, api, new ImmediateTransformer<>());
    }
    #mdevcon
    

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22. MVP: Presenter Testing
    @Test
    public void itShowsAndHidesProgressIndicator() {
    loadShiftsSuccessfully();
    verify(shiftsView).toggleProgressVisibility(true);
    verify(shiftsView).toggleProgressVisibility(false);
    }
    @Test
    public void itBindsShifts() {
    loadShiftsSuccessfully();
    verify(shiftsView).bindShifts(anyList());
    }
    #mdevcon
    

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23. MVP: Presenter Testing
    private void loadShiftsSuccessfully() {
    when(api.listShifts(any(), any()))
    .thenReturn(Observable.just(new ArrayList()));
    presenter.loadShifts(DateTime.now(), DateTime.now());
    }
    @Test
    public void itShowsErrorIfRequestFails() {
    Throwable expectedError = new Exception("Boom!");
    when(api.listShifts(any(), any())).thenReturn(Observable.error(expectedError));
    presenter.loadShifts(DateTime.now(), DateTime.now());
    verify(shiftsView).showError(eq(expectedError));
    }
    }
    #mdevcon
    

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24. #mdevcon
    

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25. Android OS
    → Fragmentation
    → Old APIs - ContentProvider, SyncAdapter,
    AccountManager, Camera, AIDL
    → Confusing flags for adjusting the view when
    showing the keyboard, launching intents, etc.
    #mdevcon
    

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26. Keyboard Input Mode
    android:windowSoftInputMode="adjustPan"
    android:windowSoftInputMode="adjustResize|stateHidden"
    android:windowSoftInputMode="dontCoverMyEditText|please"
    #mdevcon
    

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27. Intent Flags
    public static Intent newIntent(Context context, long id) {
    Intent intent = new Intent(context, TopActivity.class);
    intent.putExtra(EXTRA_ID, id);
    intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK
    | Intent.FLAG_ACTIVITY_CLEAR_TASK);
    return intent;
    }
    #mdevcon
    

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28. Fragments
    #mdevcon
    

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29. Unable to execute dex:
    method ID not in [0,
    0xffff]:
    65536
    #mdevcon
    

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30. Practicing Safe DEX
    → Choose your partners (libraries) carefully
    → Get tested regularly (method count check)
    → Use protection (Proguard & lint checks)
    #mdevcon
    

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31. Proguard: build.gradle
    buildTypes {
    debug {
    minifyEnabled true
    proguardFiles getDefaultProguardFile('proguard-android.txt'),
    'proguard-rules.pro'
    testProguardFile 'proguard-test-rules.pro'
    }
    }
    #mdevcon
    

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32. Proguard: proguard-rules.pro
    ### Retrofit, OkHttp, and RxJava
    -keepattributes Signature
    -keepattributes *Annotation*
    -keep class com.squareup.okhttp.** { *; }
    -keep interface com.squareup.okhttp.** { *; }
    -dontwarn com.squareup.okhttp.**
    -dontwarn rx.**
    -dontwarn retrofit.**
    -keep class retrofit.** { *; }
    -keepclasseswithmembers class * {
    @retrofit.http.* ;
    }
    #mdevcon
    

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33. Proguard: proguard-test-rules.pro
    -ignorewarnings # only if you're sure the remaining ones can be ignored
    -keepattributes *Annotation*
    -dontnote junit.framework.**
    -dontnote junit.runner.**
    -dontwarn android.test.**
    -dontwarn android.support.test.**
    -dontwarn org.junit.**
    -dontwarn org.hamcrest.**
    -dontwarn com.squareup.javawriter.JavaWriter
    -dontwarn org.mockito.**
    -keep class com.example.app.di.** { *; }
    #mdevcon
    

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34. #mdevcon
    

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35. Play Services
    → Consumes almost half of 65K method limit
    → Did you setup your debug SHA in the Developers
    Console? / Why isn't this JSON config file working?
    → Hard to test on emulators
    → APIs that require OAuth (i.e. Drive)
    → Constantly changing & evolving
    #mdevcon
    

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36. Play Store
    → Everyone expects your app/upgrades to be free
    → Feature ransom app reviews
    → Developer Terms violation process
    #mdevcon
    

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37. Manufacturers
    & Carriers
    → UI customizations and
    bloatware
    → Cheap phones released with
    old OS versions
    → Slow to no upgrades
    #mdevcon
    

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38. "Everything's pretty good
    and getting better"
    — Andy
    #mdevcon
    

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39. andydyer.org
    @dammitandy
    #mdevcon
    

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