BaseActivity.java

/*
 * Copyright (C) 2014 Pedro Vicente Gómez Sánchez.
 *
 * 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.pedrovgs.tuentitv.ui.activity;

import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import butterknife.ButterKnife;
import com.github.pedrovgs.tuentitv.TuentiTvApplication;
import com.github.pedrovgs.tuentitv.di.ActivityModule;
import dagger.ObjectGraph;
import java.util.List;

/**
 * Base activity created to be extended by every activity in this application. This class provides
 * dependency injection configuration, ButterKnife Android library configuration and some methods
 * common to every activity.
 *
 * @author Pedro Vicente Gómez Sánchez
 */
public abstract class BaseActivity extends FragmentActivity {

  private ObjectGraph activityObjectGraph;

  /**
   * Inject dependencies and views using Dagger and ButterKnife as libraries.
   */
  @Override protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    initializeDependencyInjectorForActivityScopeGraph();
    injectViews();
  }

  /**
   * Create a new Dagger ObjectGraph to add new dependencies using a plus operation and inject the
   * declared one in the activity. This new graph will be destroyed once the activity lifecycle
   * finish.
   *
   * This is the key of how to use Activity scope dependency injection.
   */
  private void initializeDependencyInjectorForActivityScopeGraph() {
    TuentiTvApplication app = (TuentiTvApplication) getApplication();
    List modules = getModules();
    modules.add(new ActivityModule(this));
    activityObjectGraph = app.plus(modules);
    activityObjectGraph.inject(this);
  }

  /**
   * Method created to inject dependencies in components attached to Activities like Fragments or
   * Views.
   */
  public void inject(Object object) {
    activityObjectGraph.inject(object);
  }

  /**
   * Abstract method implemented by every Activity and used to declare which modules are going to
   * provide dependencies for this component.
   */
  protected abstract List getModules();

  /**
   * Replace every field annotated with ButterKnife annotations like @InjectView with the proper
   * value.
   */
  private void injectViews() {
    ButterKnife.inject(this);
  }
}