Please look at this code:
Main activity:
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
MutableLiveData<User> mutableUser = new MutableLiveData<>();
mutableUser.setValue(new User("John","Gordon","Homeless"));
activityMainBinding = DataBindingUtil.setContentView(this, R.layout.activity_main);
activityMainBinding.setHandler(new MainActivityHandler());
activityMainBinding.setLifecycleOwner(this);
activityMainBinding.setUser(mutableUser);
setSupportActionBar(activityMainBinding.toolbar);
}
MutableLiveData is defined in xml layout:
<variable name="user" type="android.arch.lifecycle.MutableLiveData<test.databindingtemplate.ViewModels.User>"/>
Each field from user is bound to control with data binding:
<EditText
android:id="@+id/editTextName"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:ems="10"
android:inputType="textPersonName"
android:text="@={user.firstName}"
app:layout_constraintBottom_toTopOf="@+id/textViewSecondName"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toEndOf="@+id/textViewSecondName"
app:layout_constraintTop_toTopOf="parent"/>
This works fine, configuration changes are tracked and populated to gui (for example, when I type something in "Name" field, value persists when screen rotates).
Next, I want to implement refreshing user details from rest webservice - Retrofit/RxJava and I want to show busy indicator while data loading is in progress, for example, in onCreate method:
showBusyIndicator();
testService.getUserDetails(headers)
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(user ->
{
hideBusyIndicator();
activityMainBinding.getUser().setValue(user);
}, throwable ->
{
Log.d(TAG, "ERROR loading user");
hideBusyIndicator();
});
Now I'm not sure how to handle configuration changes properly - when busy indicator is shown, it should be recreated after screen rotation changes. As MutableLiveData handles configuration changes nicely, I am unable to find any solution (other than "classic" way) to solve my problem with loading indicator and handle result in this case.
Can you point me right direction?
[edit] getUserDetails declaration:
@NonNull
@GET("/user")
Observable<User> getUserDetails(@HeaderMap Map<String, String> headers);
@user8035311
I modified your github sample to trigger simulated data loading on button click, this way (button has been added to layout):
@Override
protected void onCreate(@Nullable Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
this.progressDialog = new ProgressDialog(this);
this.progressDialog.setMessage("Loading...");
final ActivityMainBinding mainBinding = DataBindingUtil.setContentView(this, R.layout.activity_main);
mainBinding.setLifecycleOwner(this);
mainBinding.button2.setOnClickListener(view ->
{
RxViewModel.RxViewModelFactory factory = new RxViewModel.RxViewModelFactory();
final RxViewModel model = ViewModelProviders.of(MainActivity.this, factory).get(RxViewModel.class);
LiveData<User> liveData = model.getLiveData();
progressDialog.show();
liveData.observe(MainActivity.this, s ->
{
progressDialog.dismiss();
mainBinding.setUser(s);
});
});
}
But this does not work. Task is interrupted on screen rotation, with exception:
06-27 09:05:18.737 11829-11829/app.rxrotation.com.architecturecomponentsrxrotation E/WindowManager: android.view.WindowLeaked: Activity app.rxrotation.com.architecturecomponentsrxrotation.MainActivity has leaked window DecorView@5b16e38[] that was originally added here at android.view.ViewRootImpl.(ViewRootImpl.java:485) at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:346) at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:93) at android.app.Dialog.show(Dialog.java:330) at app.rxrotation.com.architecturecomponentsrxrotation.MainActivity.lambda$onCreate$1$MainActivity(MainActivity.java:35) at app.rxrotation.com.architecturecomponentsrxrotation.MainActivity$$Lambda$0.onClick(Unknown Source:4) at android.view.View.performClick(View.java:6294) at android.view.View$PerformClick.run(View.java:24770) at android.os.Handler.handleCallback(Handler.java:790) at android.os.Handler.dispatchMessage(Handler.java:99) at android.os.Looper.loop(Looper.java:164) at android.app.ActivityThread.main(ActivityThread.java:6494) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)
After I click button second time, data loading not even executed.
You could use a ViewModel with LiveData to preserve your async tasks after config change. So, your LiveData could look like this:
public class UserLiveData extends LiveData<User> {
public UserLiveData() {
setValue(new User());
}
public UserLiveData(Headers headers) {
Observable<User> observable = Observable.defer(new Callable<ObservableSource<? extends User>>() {
@Override
public ObservableSource<? extends User> call() throws Exception {
User user = testService.getUserDetails(headers);
return Observable.just(user);
}
});
observable.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribeWith(new DefaultObserver<String>() {
@Override
public void onNext(User value) {
setValue(value);
}
@Override
public void onError(Throwable e) {
throw new RuntimeException(e);
}
@Override
public void onComplete() {
}
});
}
}
Then, your UserDetailsViewModel is the following:
public class UserDetailsViewModel extends ViewModel {
private LiveData<User> userLiveData;
public UserDetailsViewModel() {
userLiveData = new UserLiveData();
}
public void observeLiveDate(LifecycleOwner owner,
Observer<User> observer) {
userLiveData.observe(owner, observer);
}
public void loadLiveData(Headers headers) {
userLiveData = new UserLiveData(someArgs);
}
}
And then your MainActivity could be as following:
public class MainActivity extends AppCompatActivity {
private ProgressDialog progressDialog;
private UserViewModel viewModel;
private ActivityMainBinding mainBinding;
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.progressDialog = new ProgressDialog(this);
this.progressDialog.setMessage("Loading...");
mainBinding = DataBindingUtil.setContentView(this,
R.layout.activity_main);
mainBinding.setLifecycleOwner(this);
viewModel = ViewModelProviders.of(this).get(UserViewModel.class);
observeLiveData();
mainBinding.button2.setOnClickListener(v -> {
viewModel.initLiveData(<your headers>);
observeLiveData();
});
}
private void observeLiveData() {
progressDialog.show();
progressDialog.setCanceledOnTouchOutside(false);
viewModel.observeRxLiveDate(this, user -> {
progressDialog.dismiss();
mainBinding.setUser(user);
});
}
}
I created a very simple example here