Yeni Mimari Bileşenleri kullanmaya çalışıyorum ama aynı zamanda hantal olmak için hala yeni ve bazı şeyleri kaçırıyorum.Dagger2'yi yeni Android Architecture Bileşenleri ile düzgün bir şekilde nasıl kullanacaksınız?
Aşağıdaki kodla bir NullPointerException alıyorum, nereden bulamıyorum. Ayrıca düzeltmem veya iyileştirmem gereken başka bir şey varsa lütfen öneriniz.
KODU: ViewModel
public class PostsVM extends ViewModel {
private LiveData<StoryPost> post;
private Repository repository;
@Inject
public PostsVM(Repository repository) {
this.repository = repository;
}
public void init() {
if (this.post != null) {
return;
}
post = repository.getPosts();
}
public LiveData<StoryPost> getPost() {
return post;
}
}
Depo
@Singleton
public class Repository {
private final MutableLiveData<StoryPost> data = new MutableLiveData<>();
public LiveData<StoryPost> getPosts() {
//
new GetUser(post.getUid()) {
@Override
public void onSuccess(@NonNull User user) {
// this is where I setValue//
data.setValue(post);
}
@Override
public void onError() {
}
@Override
public void userNotFound() {
}
};
return data;
}
}
Singleton Fabrikası
@Singleton
public class ViewModelFactory implements ViewModelProvider.Factory {
private final Map<Class<? extends ViewModel>, Provider<ViewModel>> creators;
@Inject
public ViewModelFactory(Map<Class<? extends ViewModel>, Provider<ViewModel>> creators) {
this.creators = creators;
}
@SuppressWarnings("unchecked")
@Override
public <T extends ViewModel> T create(Class<T> modelClass) {
Provider<? extends ViewModel> creator = creators.get(modelClass);
if (creator == null) {
for (Map.Entry<Class<? extends ViewModel>, Provider<ViewModel>> entry : creators.entrySet()) {
if (modelClass.isAssignableFrom(entry.getKey())) {
creator = entry.getValue();
break;
}
}
}
if (creator == null) {
throw new IllegalArgumentException("unknown model class " + modelClass);
}
try {
return (T) creator.get();
} catch (Exception e) {
throw new RuntimeException(e);
}
}
}
DAO MainActivity olarak O
@Dao
public interface PostDao {
@Query("SELECT * FROM posts ORDER by time DESC")
LiveData<List<StoryPost>> getAll();
@Query("SELECT * FROM posts WHERE id = :id")
LiveData<List<StoryPost>> getPost(String id);
@Insert(onConflict = OnConflictStrategy.REPLACE)
@NonNull
void insert(StoryPost... posts);
@Delete
void delete(StoryPost post);
@Update
void update(StoryPost post);
}
:
@Inject public ViewModelFactory factory;
//...
//*onCreate*
PostsVM model = ViewModelProviders.of(this, factory).get(PostsVM.class);
model.init();
final Observer<StoryPost> observer = post -> storyAdapter.insert(post);
model.getPost().observe(this, observer);
Logcat:
... java.lang.NullPointerException: Attempt to invoke interface method
'android.arch.lifecycle.ViewModel android.arch.lifecycle.ViewModelProvider
$Factory.create(java.lang.Class)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2479)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2539)
at android.app.ActivityThread.access$900(ActivityThread.java:168)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1378)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:150)
at android.app.ActivityThread.main(ActivityThread.java:5665)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:799)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:689)
Caused by: java.lang.NullPointerException: Attempt to invoke interface method 'android.arch.lifecycle.ViewModel android.arch.lifecycle.ViewModelProvider$Factory.create(java.lang.Class)' on a null object reference
at android.arch.lifecycle.ViewModelProvider.get(ViewModelProvider.java:128)
at android.arch.lifecycle.ViewModelProvider.get(ViewModelProvider.java:96)
at com.aollay.smartpaper.MainActivity.bindDatabase(MainActivity.java:238)
at com.aollay.smartpaper.MainActivity.populateNews(MainActivity.java:233)
at com.aollay.smartpaper.MainActivity.config(MainActivity.java:159)
at com.aollay.smartpaper.MainActivity.onCreate(MainActivity.java:74)
at android.app.Activity.performCreate(Activity.java:6372)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1110)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2432)
Etkinliğinizin onCreate in InjectorClass.inject (this) denen var mı? –
@OrestSavchak, hayır ben havan't, ne 'InjectorClass' nedir – Relm
ViewModelFactory örneğini nerede oluşturuyorsunuz? –