MortarFragment.java

/*
 * Copyright (C) 2015 OpenSilk Productions LLC
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.opensilk.common.ui.mortarfragment;

import android.content.Context;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import org.opensilk.common.core.mortar.DaggerService;
import org.opensilk.common.core.mortar.HasScope;
import org.opensilk.common.ui.mortar.HasName;
import org.opensilk.common.ui.mortar.LayoutCreator;
import org.opensilk.common.ui.mortar.Lifecycle;
import org.opensilk.common.ui.mortar.LifecycleService;
import org.opensilk.common.ui.mortar.Screen;
import org.opensilk.common.ui.mortar.ScreenScoper;

import java.util.Arrays;

import javax.inject.Inject;

import mortar.MortarScope;
import rx.subjects.BehaviorSubject;
import timber.log.Timber;

/**
 * Created by drew on 3/10/15.
 */
public abstract class MortarFragment extends Fragment implements HasScope {
    private static final boolean DEBUG_LIFECYCLE = false;

    private MortarScope mScope;
    private Screen mScreen;
    private final BehaviorSubject<Lifecycle> lifecycleSubject = BehaviorSubject.create();

    protected abstract Screen newScreen();

    protected boolean shouldRetainScope() {
        return true;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        if (DEBUG_LIFECYCLE) Timber.v("->onCreate %s", getScopeName());
        super.onCreate(savedInstanceState);
        mScope = findOrMakeScope();
        setRetainInstance(shouldRetainScope());
        if (DEBUG_LIFECYCLE) Timber.v("<-onCreate %s", getScopeName());
    }

    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        LayoutCreator layoutCreator = LayoutCreator.getService(getActivity());
        Context childContext = mScope.createContext(getActivity());
        return LayoutInflater.from(childContext).inflate(layoutCreator.getLayout(getScreen()), container, false);
    }

    @Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        if (DEBUG_LIFECYCLE) Timber.v("->onActivityCreated %s", getScopeName());
        super.onActivityCreated(savedInstanceState);
        if (DEBUG_LIFECYCLE) Timber.v("<-onActivityCreated %s", getScopeName());
    }

    @Override
    public void onDestroy() {
        if (DEBUG_LIFECYCLE) Timber.v("->onDestroy %s", getScopeName());
        super.onDestroy();
        if (mScope != null) {
            Timber.d("Destroying fragment scope %s", getScopeName());
            mScope.destroy();
            mScope = null;
        }
        if (DEBUG_LIFECYCLE) Timber.v("<-onDestroy %s", getScopeName());
    }

    @Override
    public void onStart() {
        super.onStart();
        lifecycleSubject.onNext(Lifecycle.START);
    }

    @Override
    public void onResume() {
        super.onResume();
        lifecycleSubject.onNext(Lifecycle.RESUME);
    }

    @Override
    public void onPause() {
        super.onPause();
        lifecycleSubject.onNext(Lifecycle.PAUSE);
    }

    @Override
    public void onStop() {
        super.onStop();
        lifecycleSubject.onNext(Lifecycle.STOP);
    }

    private MortarScope findOrMakeScope() {
        MortarScope scope = MortarScope.findChild(getActivity(), getScopeName());
        if (scope != null) {
            Timber.d("Reusing fragment scope %s", getScopeName());
        }
        if (scope == null) {
            final ScreenScoper scoper = ScreenScoper.getService(getActivity());
            final Object[] otherServices = getAdditionalServices();
            final Object[] services;
            if (otherServices == null || otherServices.length == 0) {
                services = new Object[] {
                        LifecycleService.LIFECYCLE_SERVICE,
                        lifecycleSubject.asObservable()
                };
            } else {
                services = new Object[otherServices.length + 2];
                System.arraycopy(otherServices, 0, services, 0, otherServices.length);
                services[services.length-2] = LifecycleService.LIFECYCLE_SERVICE;
                services[services.length-1] = lifecycleSubject.asObservable();
            }
            scope = scoper.getScreenScope(getActivity(), getScreen(), services);
            Timber.d("Created new fragment scope %s", getScopeName());
        }
        return scope;
    }

    //Enforce using screen name as scope name, this is also used to tag the fragment
    public final String getScopeName() {
        return getScreen().getName();
    }

    @Override
    public final @NonNull MortarScope getScope() {
        if (mScope == null) {
            throw new IllegalStateException("Can't call getScope() before onCreate()");
        }
        return mScope;
    }

    public final @NonNull Screen getScreen() {
        if (mScreen == null) {
            mScreen = newScreen();
        }
        return mScreen;
    }

    /**
     * Override to add additional services to this scope
     * @return Name(string), Object(service)
     */
    protected Object[] getAdditionalServices() {
        return null;
    }

    public static <T extends MortarFragment> T factory(Context context, String name, Bundle args) {
        return (T) Fragment.instantiate(context, name, args);
    }
}