FragmentLifecycleProviderImpl.java

package com.trello.rxlifecycle.navi;

import android.support.annotation.CheckResult;
import android.support.annotation.NonNull;
import com.trello.navi.Event;
import com.trello.navi.NaviComponent;
import com.trello.navi.rx.RxNavi;
import com.trello.rxlifecycle.LifecycleProvider;
import com.trello.rxlifecycle.LifecycleTransformer;
import com.trello.rxlifecycle.RxLifecycle;
import com.trello.rxlifecycle.android.FragmentEvent;
import com.trello.rxlifecycle.android.RxLifecycleAndroid;
import rx.Observable;
import rx.subjects.BehaviorSubject;

final class FragmentLifecycleProviderImpl implements LifecycleProvider<FragmentEvent> {
    private final BehaviorSubject<FragmentEvent> lifecycleSubject = BehaviorSubject.create();

    public FragmentLifecycleProviderImpl(final NaviComponent fragment) {
        if (!fragment.handlesEvents(Event.ATTACH, Event.CREATE, Event.CREATE_VIEW, Event.START, Event.RESUME,
            Event.PAUSE, Event.STOP, Event.DESTROY_VIEW, Event.DESTROY, Event.DETACH)) {
            throw new IllegalArgumentException("NaviComponent does not handle all required events");
        }

        RxNavi.observe(fragment, Event.ALL)
            .map(NaviLifecycleMaps.FRAGMENT_EVENT_MAP)
            .filter(RxUtils.notNull())
            .subscribe(lifecycleSubject);
    }

    @Override
    @NonNull
    @CheckResult
    public Observable<FragmentEvent> lifecycle() {
        return lifecycleSubject.asObservable();
    }

    @Override
    @NonNull
    @CheckResult
    public <T> LifecycleTransformer<T> bindUntilEvent(@NonNull FragmentEvent event) {
        return RxLifecycle.bindUntilEvent(lifecycleSubject, event);
    }

    @Override
    @NonNull
    @CheckResult
    public <T> LifecycleTransformer<T> bindToLifecycle() {
        return RxLifecycleAndroid.bindFragment(lifecycleSubject);
    }
}