Dagger2 Optional bindings

Transcript

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6. &OUSZ public class Entry {
 public final String title;
 public Entry(String title) {
 this.title = title;
 }
 }
7. .PEVMF
   BCTUSBDU @Module
 public abstract class MainModule {
 @BindsOptionalOf
 public abstract Entry optionalEntryProvider();
 }
8. $PNQPOFOU @Component(modules = {MainModule.class})
 public interface MainComponent {
 Optional<Entry> entry();
 }
9. .BJO"DUJWJUZ public class MainActivity extends AppCompatActivity {
 …
 MainComponent mainComponent = DaggerMainComponent.create();
 
 Optional<Entry> entry = mainComponent.entry();
 Log.e(“entry”, entry.or(new Entry(“default")).title); …
 } w EFGBVMU
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10. .PEVMF @Module
 public class EntryModule {
 @Provides
 public Entry provideEntry() {
 return new Entry(“entry");
 }
 }
11. $PNQPOFOU @Component(modules = {MainModule.class, EntryModule.class})
 public interface MainComponent {
 Optional<Entry> entry();
 }
12. .BJO"DUJWJUZ public class MainActivity extends AppCompatActivity {
 …
 Optional<Entry> entry = mainComponent.entry();
 Log.e(“entry”, entry.or(new Entry(“default")).title); …
 } w FOUSZ
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13. $PNQPOFOU
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15. 0QUJPOBM
    ΛίϯετϥΫλ Ͱड͚औΔΫϥε public class EntryManager {
 private final Entry mEntry;
 @Inject
 public EntryManager(Optional<Entry> entryOptional) {
 mEntry = entryOptional.or(new Entry("default"));
 }
 
 public String getTitle() {
 return mEntry.title;
 }
 }
16. &OUSZ
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    $PNQPOFOU @Subcomponent
 public interface EmptyComponent {
 void inject(MainActivity activity);
 @Subcomponent.Builder
 interface Builder {
 EmptyComponent build();
 }
 }
17. &OUSZ
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    $PNQPOFOU @Subcomponent(modules = SavedEntryModule.class)
 public interface SavedEntryComponent {
 void inject(MainActivity activity);
 @Subcomponent.Builder
 interface Builder {
 SavedEntryComponent build();
 }
 }
18. &OUSZ
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    $PNQPOFOU @Module
 public class SavedEntryModule {
 @Provides Entry provideEntry() {
 return new Entry("saved");
 }
 }
19. "DUJWJUZ public class MainActivity extends AppCompatActivity {
 @Inject EntryManager mEntryManager;
 …
 DaggerMainComponent
 .create()
 .emptyComponent()
 .build()
 .inject(this);
 Log.e("title", mEntryManager.getTitle()); // default
 
 DaggerMainComponent
 .create()
 .savedEntryComponent()
 .build()
 .inject(this);
 Log.e("title", mEntryManager.getTitle()); // saved
 }
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