I’ve searched for my problem nearly whole the Internet and couldn’t find the answer, which I need. Yes. My question is not unique, but there was no answer, which could help me. So I decided to ask it myself.
Now about the problem:
public class AuthActivityViewModel extends AndroidViewModel {
Repository repository;
private LiveData<List<User>> users;
private LiveData<User> user;
public AuthActivityViewModel(@NonNull Application application) {
super(application);
repository = new Repository(application);
}
public LiveData<List<User>> getUsers() {
users = repository.getUsers();
return users;
}
public LiveData<User> getUser(int userId) {
user = repository.getUser(userId);
return user;
}
public void addNewUser(User user) {
repository.insertUser(user);
}
public void updateUser(User user) {
repository.updateUser(user);
}
public void deleteUser(User user) {
repository.deleteUser(user);
}
}
……………………………………..
public class AuthActivity extends AppCompatActivity implements AuthInteractionListener {
private FragmentManager fragmentManager;
private final ConnectionBroadcastReceiver connectionBroadcastReceiver = new ConnectionBroadcastReceiver();
private int limitOfOnWindowFocusChangedOperationForAuthActivity = 0;
private boolean isActivityRecreated;
AuthActivityViewModel authActivityViewModel;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_auth);
isActivityRecreated = true;
IntentFilter connectionIntentFilter = new IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION);
registerReceiver(connectionBroadcastReceiver, connectionIntentFilter);
authActivityViewModel = new ViewModelProvider(this).get(AuthActivityViewModel.class);
}
...
}
………….
Error:
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.android.findthepikachuupgradeversion2/com.example.android.findthepikachuupgradeversion3.view.AuthActivity}: java.lang.RuntimeException: Cannot create an instance of class com.example.android.findthepikachuupgradeversion3.viewmodel.AuthActivityViewModel
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3307)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3446)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2043)
at android.os.Handler.dispatchMessage(Handler.java:107)
at android.os.Looper.loop(Looper.java:224)
at android.app.ActivityThread.main(ActivityThread.java:7548)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:539)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:950)
Caused by: java.lang.RuntimeException: Cannot create an instance of class com.example.android.findthepikachuupgradeversion3.viewmodel.AuthActivityViewModel
at androidx.lifecycle.ViewModelProvider$NewInstanceFactory.create(ViewModelProvider.java:221)
at androidx.lifecycle.ViewModelProvider.get(ViewModelProvider.java:187)
at androidx.lifecycle.ViewModelProvider.get(ViewModelProvider.java:150)
at com.example.android.findthepikachuupgradeversion3.view.AuthActivity.onCreate(AuthActivity.java:44)
at android.app.Activity.performCreate(Activity.java:7893)
at android.app.Activity.performCreate(Activity.java:7880)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1307)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3282)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3446)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2043)
at android.os.Handler.dispatchMessage(Handler.java:107)
at android.os.Looper.loop(Looper.java:224)
at android.app.ActivityThread.main(ActivityThread.java:7548)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:539)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:950)
Caused by: java.lang.InstantiationException: java.lang.Class<com.example.android.findthepikachuupgradeversion3.viewmodel.AuthActivityViewModel> has no zero argument constructor
at java.lang.Class.newInstance(Native Method)
at androidx.lifecycle.ViewModelProvider$NewInstanceFactory.create(ViewModelProvider.java:219)
at androidx.lifecycle.ViewModelProvider.get(ViewModelProvider.java:187)
at androidx.lifecycle.ViewModelProvider.get(ViewModelProvider.java:150)
at com.example.android.findthepikachuupgradeversion3.view.AuthActivity.onCreate(AuthActivity.java:44)
at android.app.Activity.performCreate(Activity.java:7893)
at android.app.Activity.performCreate(Activity.java:7880)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1307)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3282)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3446)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2043)
at android.os.Handler.dispatchMessage(Handler.java:107)
at android.os.Looper.loop(Looper.java:224)
at android.app.ActivityThread.main(ActivityThread.java:7548)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:539)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:950)
- I tried to add a constructor with no arguments in class AuthActivityViewModel, but got this error
There is no default constructor available in androidx.lifecycle.AndroidViewModel
Advices like
- https://stackoverflow.com/a/54462438/14048134
- Make sure your view model class constructor is public.
- Make sure you have added the dependency in your gradle file for lifecycle
are not actual. Why? Cause they were already as they should be, but I have the error which must not be. As the problem exists, there must be something that I didn’t count.
Here is some part of the gradle file:
def lifecycle_version = “2.2.0” implementation “androidx.lifecycle:lifecycle-viewmodel:$lifecycle_version”
implementation "androidx.lifecycle:lifecycle-livedata:$lifecycle_version"
annotationProcessor "androidx.lifecycle:lifecycle-compiler:$lifecycle_version"
def room_version = "2.2.5"
implementation "androidx.room:room-runtime:$room_version"
annotationProcessor "androidx.room:room-compiler:$room_version"
How can I solve this problem?
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Answer
Add the below dependency to gradle app module level.
implementation 'androidx.lifecycle:lifecycle-extensions:$lifecycle_version
Extensions include many libraries including LiveData, So, by adding it, you can get rid of:
implementation 'androidx.lifecycle:lifecycle-livedata:$lifecycle_version
But it appears lifecycle-extensions has been deprecated. Is there another dependency that solves this issue?
That is right it’s been deprecated as of version:2.2.0.
lifecycle-extensions Artifact Deprecation: With the above deprecation of ViewModelProviders.of(), this release marks the deprecation of the last API in lifecycle-extensions and this artifact should now be considered deprecated in its entirety. We strongly recommend depending on the specific Lifecycle artifacts you need (such as lifecycle-service if you’re using LifecycleService and lifecycle-process if you’re using ProcessLifecycleOwner) rather than lifecycle-extensions as there will not be a future 2.3.0 release of lifecycle-extensions.
As quoted by documentation, you can instead use the specific Lifecycle artifacts: And as we discussed in comments the specific lifecycler aritifacts that works was:
implementation "android.arch.lifecycle:runtime:$lifecycle_version
And also keep the other lifecycler dependency artifacts of yours.