content: /**
   * Copyright (c) 2018 The Android Open Source Project
   *
   * 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.android.launcher3;
  
  import android.app.Application;
  import android.content.BroadcastReceiver;
  import android.content.Context;
  import android.content.Intent;
  import android.content.IntentFilter;
  import android.content.pm.PackageManager;
  import android.content.pm.ResolveInfo;
  import android.os.AsyncTask;
  
  import androidx.lifecycle.AndroidViewModel;
  import androidx.lifecycle.LiveData;
  
  import java.util.ArrayList;
  import java.util.List;
  
  /**
   * A view model that provides a list of activities that can be launched.
   */
  public class AppListViewModel extends AndroidViewModel {
  
      private final AppListLiveData mLiveData;
      private final PackageIntentReceiver
              mPackageIntentReceiver;
  
      public AppListViewModel(Application application) {
          super(application);
          mLiveData = new AppListLiveData(application);
          mPackageIntentReceiver = new PackageIntentReceiver(mLiveData, application);
      }
  
      public LiveData<List<AppEntry>> getAppList() {
          return mLiveData;
      }
  
      protected void onCleared() {
          getApplication().unregisterReceiver(mPackageIntentReceiver);
      }
  }
  
  class AppListLiveData extends LiveData<List<AppEntry>> {
  
      private final PackageManager mPackageManager;
      private int mCurrentDataVersion;
  
      public AppListLiveData(Context context) {
          mPackageManager = context.getPackageManager();
          loadData();
      }
  
      void loadData() {
          final int loadDataVersion = ++mCurrentDataVersion;
  
          new AsyncTask<Void, Void, List<AppEntry>>() {
              @Override
              protected List<AppEntry> doInBackground(Void... voids) {
                  Intent mainIntent = new Intent(Intent.ACTION_MAIN, null);
                  mainIntent.addCategory(Intent.CATEGORY_LAUNCHER);
  
                  List<ResolveInfo> apps = mPackageManager.queryIntentActivities(mainIntent,
                          PackageManager.GET_META_DATA);
  
                  List<AppEntry> entries = new ArrayList<>();
                  if (apps != null) {
                      for (ResolveInfo app : apps) {
                          AppEntry entry = new AppEntry(app, mPackageManager);
                          entries.add(entry);
                      }
                  }
                  return entries;
              }
  
              @Override
              protected void onPostExecute(List<AppEntry> data) {
                  if (mCurrentDataVersion == loadDataVersion) {
                      setValue(data);
                  }
              }
          }.execute();
      }
  }
  
  /**
   * Receiver used to notify live data about app list changes.
   */
  class PackageIntentReceiver extends BroadcastReceiver {
  
      private final AppListLiveData mLiveData;
  
      public PackageIntentReceiver(AppListLiveData liveData, Context context) {
          mLiveData = liveData;
          IntentFilter filter = new IntentFilter(Intent.ACTION_PACKAGE_ADDED);
          filter.addAction(Intent.ACTION_PACKAGE_REMOVED);
          filter.addAction(Intent.ACTION_PACKAGE_CHANGED);
          filter.addDataScheme("package");
          context.registerReceiver(this, filter);
  
          // Register for events related to sdcard installation.
          IntentFilter sdFilter = new IntentFilter();
          sdFilter.addAction(Intent.ACTION_EXTERNAL_APPLICATIONS_AVAILABLE);
          sdFilter.addAction(Intent.ACTION_EXTERNAL_APPLICATIONS_UNAVAILABLE);
          context.registerReceiver(this, sdFilter);
      }
  
      @Override
      public void onReceive(Context context, Intent intent) {
          mLiveData.loadData();
      }
  }