rx.android.app.AppObservable Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of rxandroid Show documentation
rxandroid
There is a newer version: 1.2.1
/**
 * 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 rx.android.app;

import android.app.Activity;
import android.app.Fragment;
import android.os.Build;

import rx.Observable;
import rx.android.internal.Assertions;
import rx.functions.Func1;

import static rx.android.schedulers.AndroidSchedulers.mainThread;

public final class AppObservable {
    private AppObservable() {
        throw new AssertionError("No instances");
    }

    static {
        boolean supportFragmentsAvailable = false;
        try {
            Class.forName("android.support.v4.app.Fragment");
            supportFragmentsAvailable = true;
        } catch (ClassNotFoundException e) {
        }

        USES_SUPPORT_FRAGMENTS = supportFragmentsAvailable;
    }

    private static final Func1 ACTIVITY_VALIDATOR = new Func1() {
        @Override
        public Boolean call(Activity activity) {
            return !activity.isFinishing();
        }
    };
    private static final Func1 FRAGMENT_VALIDATOR = new Func1() {
        @Override
        public Boolean call(Fragment fragment) {
            return fragment.isAdded() && !fragment.getActivity().isFinishing();
        }
    };
    private static final Func1 FRAGMENTV4_VALIDATOR =
            new Func1() {
                @Override
                public Boolean call(android.support.v4.app.Fragment fragment) {
                    return fragment.isAdded() && !fragment.getActivity().isFinishing();
                }
            };
    public static final boolean USES_SUPPORT_FRAGMENTS;

    /**
     * Binds the given source sequence to an activity.
     * 
     * This helper will schedule the given sequence to be observed on the main UI thread and ensure
     * that no notifications will be forwarded to the activity in case it is scheduled to finish.
     * 

     * You should unsubscribe from the returned Observable in onDestroy at the latest, in order to not
     * leak the activity or an inner subscriber. Conversely, when the source sequence can outlive the activity,
     * make sure to bind to new instances of the activity again, e.g. after going through configuration changes.
     * Refer to the samples project for actual examples.
     *
     * @param activity the activity to bind the source sequence to
     * @param source   the source sequence
     */
    public static  Observable bindActivity(Activity activity, Observable source) {
        Assertions.assertUiThread();
        return source.observeOn(mainThread()).lift(new OperatorConditionalBinding(activity, ACTIVITY_VALIDATOR));
    }

    /**
     * Binds the given source sequence to a fragment (native or support-v4).
     * 

     * This helper will schedule the given sequence to be observed on the main UI thread and ensure
     * that no notifications will be forwarded to the fragment in case it gets detached from its
     * activity or the activity is scheduled to finish.
     * 
     * You should unsubscribe from the returned Observable in onDestroy for normal fragments, or in onDestroyView
     * for retained fragments, in order to not leak any references to the host activity or the fragment.
     * Refer to the samples project for actual examples.
     *
     * @param fragment the fragment to bind the source sequence to
     * @param source   the source sequence
     */
    public static  Observable bindFragment(Object fragment, Observable source) {
        Assertions.assertUiThread();
        final Observable o = source.observeOn(mainThread());
        if (USES_SUPPORT_FRAGMENTS && fragment instanceof android.support.v4.app.Fragment) {
            android.support.v4.app.Fragment f = (android.support.v4.app.Fragment) fragment;
            return o.lift(new OperatorConditionalBinding(f, FRAGMENTV4_VALIDATOR));
        } else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB && fragment instanceof Fragment) {
            Fragment f = (Fragment) fragment;
            return o.lift(new OperatorConditionalBinding(f, FRAGMENT_VALIDATOR));
        } else {
            throw new IllegalArgumentException("Target fragment is neither a native nor support library Fragment");
        }
    }
}