AccountAuthenticatorAppCompatActivity.java

/*
 * Copyright (c) 2015 PocketHub
 *
 * 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 com.github.pockethub.android.ui.roboactivities;

import android.accounts.AccountAuthenticatorResponse;
import android.accounts.AccountManager;
import android.os.Bundle;
import android.support.annotation.CallSuper;
import android.support.v7.app.AppCompatActivity;

import com.trello.rxlifecycle2.LifecycleProvider;
import com.trello.rxlifecycle2.LifecycleTransformer;
import com.trello.rxlifecycle2.RxLifecycle;
import com.trello.rxlifecycle2.android.ActivityEvent;
import com.trello.rxlifecycle2.android.RxLifecycleAndroid;

import io.reactivex.Observable;
import io.reactivex.subjects.BehaviorSubject;

/**
 * Base class for implementing an Activity that is used to help implement an
 * AbstractAccountAuthenticator. If the AbstractAccountAuthenticator needs to use an activity
 * to handle the request then it can have the activity extend ActionBarAccountAuthenticatorActivity.
 * The AbstractAccountAuthenticator passes in the response to the intent using the following:
 * <pre>
 *      intent.putExtra({@link AccountManager#KEY_ACCOUNT_AUTHENTICATOR_RESPONSE}, response);
 * </pre>
 * The activity then sets the result that is to be handed to the response via
 * {@link #setAccountAuthenticatorResult(Bundle)}.
 * This result will be sent as the result of the request when the activity finishes. If this
 * is never set or if it is set to null then error {@link AccountManager#ERROR_CODE_CANCELED}
 * will be called on the response.
 *
 * Based on <a href="https://github.com/mccrajs">@mccrajs's</a> implementation <a href="https://github.com/rtyley/roboguice-sherlock/blob/master/src/main/java/com/github/rtyley/android/sherlock/android/accounts/SherlockAccountAuthenticatorActivity.java">here</a>.
 */
public class AccountAuthenticatorAppCompatActivity extends AppCompatActivity implements LifecycleProvider<ActivityEvent> {
    private AccountAuthenticatorResponse mAccountAuthenticatorResponse = null;
    private Bundle mResultBundle = null;

    private final BehaviorSubject<ActivityEvent> lifecycleSubject = BehaviorSubject.create();

    @Override
    public final Observable<ActivityEvent> lifecycle() {
        return lifecycleSubject;
    }

    @Override
    public final <T> LifecycleTransformer<T> bindUntilEvent(ActivityEvent event) {
        return RxLifecycle.bindUntilEvent(lifecycleSubject, event);
    }

    @Override
    public final <T> LifecycleTransformer<T> bindToLifecycle() {
        return RxLifecycleAndroid.bindActivity(lifecycleSubject);
    }

    @Override
    @CallSuper
    protected void onStart() {
        super.onStart();
        lifecycleSubject.onNext(ActivityEvent.START);
    }

    @Override
    @CallSuper
    protected void onResume() {
        super.onResume();
        lifecycleSubject.onNext(ActivityEvent.RESUME);
    }

    @Override
    @CallSuper
    protected void onPause() {
        lifecycleSubject.onNext(ActivityEvent.PAUSE);
        super.onPause();
    }

    @Override
    @CallSuper
    protected void onStop() {
        lifecycleSubject.onNext(ActivityEvent.STOP);
        super.onStop();
    }

    @Override
    @CallSuper
    protected void onDestroy() {
        lifecycleSubject.onNext(ActivityEvent.DESTROY);
        super.onDestroy();
    }

    /**
     * Set the result that is to be sent as the result of the request that caused this
     * Activity to be launched. If result is null or this method is never called then
     * the request will be canceled.
     * @param result this is returned as the result of the AbstractAccountAuthenticator request
     */
    public final void setAccountAuthenticatorResult(Bundle result) {
        mResultBundle = result;
    }

    /**
     * Retreives the AccountAuthenticatorResponse from either the intent of the icicle, if the
     * icicle is non-zero.
     * @param icicle the save instance data of this Activity, may be null
     */
    @Override
    protected void onCreate(Bundle icicle) {
        super.onCreate(icicle);
        lifecycleSubject.onNext(ActivityEvent.CREATE);

        mAccountAuthenticatorResponse =
            getIntent().getParcelableExtra(AccountManager.KEY_ACCOUNT_AUTHENTICATOR_RESPONSE);

        if (mAccountAuthenticatorResponse != null) {
            mAccountAuthenticatorResponse.onRequestContinued();
        }
    }

    /**
     * Sends the result or a Constants.ERROR_CODE_CANCELED error if a result isn't present.
     */
    @Override
    public void finish() {
        if (mAccountAuthenticatorResponse != null) {
            // send the result bundle back if set, otherwise send an error.
            if (mResultBundle != null) {
                mAccountAuthenticatorResponse.onResult(mResultBundle);
            } else {
                mAccountAuthenticatorResponse.onError(AccountManager.ERROR_CODE_CANCELED,
                    "canceled");
            }
            mAccountAuthenticatorResponse = null;
        }
        super.finish();
    }
}