I am using Android Support Library 26.1.0. These are the dependencies in app module -
implementation "android.arch.lifecycle:runtime:1.0.0"
implementation "android.arch.lifecycle:extensions:1.0.0-beta1"
implementation "android.arch.persistence.room:rxjava2:1.0.0-beta1"
implementation "android.arch.lifecycle:common-java8:1.0.0-beta1"
annotationProcessor "android.arch.lifecycle:compiler:1.0.0-beta1"
But when I am trying to use ViewModel like below -
mUserViewModel.getUsers().observe(this,
(Observer<Resource<List<UserView>>>) listResource -> {
if(listResource != null){
this.handleDataState(listResource.status, listResource.data, listResource.message);
}
});
It is showing error at this
and the error message is Wrong first argument type Found: packagename.BrowseActivity, required: android.arch.lifecycle.LifecycleOwner
. (Although support library version is 26.1+ which already implements LifecycleOwner)
I have also tried to implement LifecycleRegistryOwner
which I found in this sample and this is also not working. Kindly suggest a solution and let me know if I am doing anything wrong.
Edit 1 - This is Activity class
import android.arch.lifecycle.Observer;
import android.arch.lifecycle.ViewModelProviders;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.widget.ProgressBar;
import com.github.amitkma.boilerplate.app.R;
import com.github.amitkma.boilerplate.app.mapper.UserMapper;
import com.github.amitkma.boilerplate.app.model.UserModel;
import com.github.amitkma.boilerplate.app.ui.widget.EmptyView;
import com.github.amitkma.boilerplate.app.ui.widget.ErrorView;
import com.github.amitkma.boilerplate.presentation.data.Resource;
import com.github.amitkma.boilerplate.presentation.data.ResourceState;
import com.github.amitkma.boilerplate.presentation.factory.ViewModelFactory;
import com.github.amitkma.boilerplate.presentation.viewmodel.UserViewModel;
import com.github.amitkma.boilerplate.presentation.vo.UserView;
import java.util.ArrayList;
import java.util.List;
import javax.inject.Inject;
import dagger.android.AndroidInjection;
public class BrowseActivity extends AppCompatActivity {
@Inject
UserAdapter mUserAdapter;
@Inject
UserMapper mUserMapper;
@Inject
ViewModelFactory mViewModelFactory;
private UserViewModel mUserViewModel;
private RecyclerView mRecyclerView;
private ProgressBar mProgressBar;
private ErrorView mErrorView;
private EmptyView mEmptyView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
AndroidInjection.inject(this);
setContentView(R.layout.activity_browse);
mUserViewModel = ViewModelProviders.of(this, mViewModelFactory)
.get(UserViewModel.class);
mRecyclerView = findViewById(R.id.recycler_browse);
mProgressBar = findViewById(R.id.progress);
mEmptyView = findViewById(R.id.view_empty);
mErrorView = findViewById(R.id.view_error);
setupBrowseRecycler();
setupViewListeners();
}
@Override
protected void onStart() {
super.onStart();
mUserViewModel.getUsers().observe(this,
(Observer<Resource<List<UserView>>>) listResource -> {
if(listResource != null){
this.handleDataState(listResource.status, listResource.data, listResource.message);
}
});
}
....
}
This is ViewModel Class
import android.arch.lifecycle.LiveData;
import android.arch.lifecycle.MutableLiveData;
import android.arch.lifecycle.ViewModel;
import com.github.amitkma.boilerplate.domain.interactor.GetUserList;
import com.github.amitkma.boilerplate.domain.model.User;
import com.github.amitkma.boilerplate.presentation.data.Resource;
import com.github.amitkma.boilerplate.presentation.data.ResourceState;
import com.github.amitkma.boilerplate.presentation.mapper.UserMapper;
import com.github.amitkma.boilerplate.presentation.vo.UserView;
import java.util.ArrayList;
import java.util.List;
import javax.inject.Inject;
import io.reactivex.subscribers.DisposableSubscriber;
public class UserViewModel extends ViewModel {
private final GetUserList mGetUserList;
private final UserMapper mUserMapper;
@Inject
public UserViewModel(GetUserList getUserList,
UserMapper userMapper) {
mGetUserList = getUserList;
mUserMapper = userMapper;
fetchUsers();
}
public void fetchUsers(){
mUserMutableLiveData.postValue(new Resource(ResourceState.LOADING, null, null));
mGetUserList.execute(new UserSubscriber(), null);
}
public LiveData<Resource<List<UserView>>> getUsers(){
return mUserMutableLiveData;
}
@Override
protected void onCleared() {
mGetUserList.dispose();
super.onCleared();
}
private final MutableLiveData<Resource<List<UserView>>> mUserMutableLiveData =
new MutableLiveData<>();
}
Every Activity has a Lifecycle. This Activity will be a Lifecycle Owner(any activity or fragment can be called a lifecycle owner). When an activity is initialized LifecycleOwner is the one that will be constructed initially. Any class that implements the LifeCycleOwner interface indicates that it has Android LifeCycle.
Step 1: Define LiveData object to store data and a method to observe that data in View class. Step 3: Define viewModel object in activity. this refers to an instance of lifecycleOwner . We are observing Data changes in activity so activity will be notified when live data has been set.
Lifecycle Awareness: ViewModel objects are also lifecycle-aware. They are automatically cleared when the Lifecycle they are observing gets permanently destroyed.
When using a ViewModel exposing LiveData s for a Fragment , there are currently two LifecycleOwners that can be used to oberve: the Fragment itself or. the Fragment 's property mViewLifecycleOwner .
Same problem here, so I had to update my androidx.appcompat dependency, like below:
implementation 'androidx.appcompat:appcompat:1.1.0-alpha04'
You don't need to implement this anymore.
Just extend your activity by AppCompatActivity which extends LifecycleOwner.
This interface was deprecated in API level 1.0.0. Use android.support.v7.app.AppCompatActivity which extends LifecycleOwner, so there are no use cases for this class.
You forgot to override
private final LifecycleRegistry lifecycleRegistry = new LifecycleRegistry(this);
@Override
public LifecycleRegistry getLifecycle() {
return lifecycleRegistry;
}
You need at least Support-Lib 26.1
Same for fragments. Just extend your Fragment by LifecycleFragment
which extends android.support.v4.app.Fragment
Edit: Just rebuilt a quick sample project using Kotlin and it worked.
class MainActivity : AppCompatActivity(), HasSupportFragmentInjector, AnkoLogger {
private val lifecycleRegistry by lazy { android.arch.lifecycle.LifecycleRegistry(this) }
private val viewModel by lazy { ViewModelProviders.of(this, viewModelFactory).get(BridgesVm::class.java) }
override fun getLifecycle() = lifecycleRegistry
public override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
viewModel.data.observe(this, Observer<Bridge?> { info { "Received" } })
}
}
class BridgesVm @Inject constructor() : ViewModel() {
val data: LiveData<Bridge> = MutableLiveData<Bridge>()
}
Edit:
There's a problem using arch version beta1. Consider using 1.0.0-alpha9-1 until this is fixed. In my case it wasnt working if i use beta1 but working with alpha 9-1
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