LoaderCustomSupport.java revision b31c3281d870e9abb673db239234d580dcc4feff
1/* 2 * Copyright (C) 2010 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17package com.example.android.supportv4.app; 18 19import android.content.BroadcastReceiver; 20import android.content.Context; 21import android.content.Intent; 22import android.content.IntentFilter; 23import android.content.pm.ActivityInfo; 24import android.content.pm.ApplicationInfo; 25import android.content.pm.PackageManager; 26import android.content.res.Configuration; 27import android.content.res.Resources; 28import android.graphics.drawable.Drawable; 29import android.os.Bundle; 30import androidx.annotation.NonNull; 31import androidx.fragment.app.FragmentActivity; 32import androidx.fragment.app.FragmentManager; 33import androidx.fragment.app.ListFragment; 34import androidx.loader.app.LoaderManager; 35import androidx.loader.content.AsyncTaskLoader; 36import androidx.core.content.ContextCompat; 37import androidx.loader.content.Loader; 38import android.text.TextUtils; 39import android.util.Log; 40import android.view.LayoutInflater; 41import android.view.Menu; 42import android.view.MenuInflater; 43import android.view.MenuItem; 44import android.view.View; 45import android.view.ViewGroup; 46import android.widget.ArrayAdapter; 47import android.widget.ImageView; 48import android.widget.ListView; 49import android.widget.SearchView; 50import android.widget.TextView; 51 52import com.example.android.supportv4.R; 53 54import java.io.File; 55import java.text.Collator; 56import java.util.ArrayList; 57import java.util.Collections; 58import java.util.Comparator; 59import java.util.List; 60 61/** 62 * Demonstration of the implementation of a custom Loader. 63 */ 64public class LoaderCustomSupport extends FragmentActivity { 65 66 @Override 67 protected void onCreate(Bundle savedInstanceState) { 68 super.onCreate(savedInstanceState); 69 70 FragmentManager fm = getSupportFragmentManager(); 71 72 // Create the list fragment and add it as our sole content. 73 if (fm.findFragmentById(android.R.id.content) == null) { 74 AppListFragment list = new AppListFragment(); 75 fm.beginTransaction().add(android.R.id.content, list).commit(); 76 } 77 } 78 79//BEGIN_INCLUDE(loader) 80 /** 81 * This class holds the per-item data in our Loader. 82 */ 83 public static class AppEntry { 84 public AppEntry(AppListLoader loader, ApplicationInfo info) { 85 mLoader = loader; 86 mInfo = info; 87 mApkFile = new File(info.sourceDir); 88 } 89 90 public ApplicationInfo getApplicationInfo() { 91 return mInfo; 92 } 93 94 public String getLabel() { 95 return mLabel; 96 } 97 98 public Drawable getIcon() { 99 if (mIcon == null) { 100 if (mApkFile.exists()) { 101 mIcon = mInfo.loadIcon(mLoader.mPm); 102 return mIcon; 103 } else { 104 mMounted = false; 105 } 106 } else if (!mMounted) { 107 // If the app wasn't mounted but is now mounted, reload 108 // its icon. 109 if (mApkFile.exists()) { 110 mMounted = true; 111 mIcon = mInfo.loadIcon(mLoader.mPm); 112 return mIcon; 113 } 114 } else { 115 return mIcon; 116 } 117 118 return ContextCompat.getDrawable( 119 mLoader.getContext(), android.R.drawable.sym_def_app_icon); 120 } 121 122 @Override public String toString() { 123 return mLabel; 124 } 125 126 void loadLabel(Context context) { 127 if (mLabel == null || !mMounted) { 128 if (!mApkFile.exists()) { 129 mMounted = false; 130 mLabel = mInfo.packageName; 131 } else { 132 mMounted = true; 133 CharSequence label = mInfo.loadLabel(context.getPackageManager()); 134 mLabel = label != null ? label.toString() : mInfo.packageName; 135 } 136 } 137 } 138 139 private final AppListLoader mLoader; 140 private final ApplicationInfo mInfo; 141 private final File mApkFile; 142 private String mLabel; 143 private Drawable mIcon; 144 private boolean mMounted; 145 } 146 147 /** 148 * Perform alphabetical comparison of application entry objects. 149 */ 150 public static final Comparator<AppEntry> ALPHA_COMPARATOR = new Comparator<AppEntry>() { 151 private final Collator sCollator = Collator.getInstance(); 152 @Override 153 public int compare(AppEntry object1, AppEntry object2) { 154 return sCollator.compare(object1.getLabel(), object2.getLabel()); 155 } 156 }; 157 158 /** 159 * Helper for determining if the configuration has changed in an interesting 160 * way so we need to rebuild the app list. 161 */ 162 public static class InterestingConfigChanges { 163 final Configuration mLastConfiguration = new Configuration(); 164 int mLastDensity; 165 166 boolean applyNewConfig(Resources res) { 167 int configChanges = mLastConfiguration.updateFrom(res.getConfiguration()); 168 boolean densityChanged = mLastDensity != res.getDisplayMetrics().densityDpi; 169 if (densityChanged || (configChanges & (ActivityInfo.CONFIG_LOCALE 170 | ActivityInfo.CONFIG_UI_MODE | ActivityInfo.CONFIG_SCREEN_LAYOUT)) != 0) { 171 mLastDensity = res.getDisplayMetrics().densityDpi; 172 return true; 173 } 174 return false; 175 } 176 } 177 178 /** 179 * Helper class to look for interesting changes to the installed apps 180 * so that the loader can be updated. 181 */ 182 public static class PackageIntentReceiver extends BroadcastReceiver { 183 final AppListLoader mLoader; 184 185 public PackageIntentReceiver(AppListLoader loader) { 186 mLoader = loader; 187 IntentFilter filter = new IntentFilter(Intent.ACTION_PACKAGE_ADDED); 188 filter.addAction(Intent.ACTION_PACKAGE_REMOVED); 189 filter.addAction(Intent.ACTION_PACKAGE_CHANGED); 190 filter.addDataScheme("package"); 191 mLoader.getContext().registerReceiver(this, filter); 192 // Register for events related to sdcard installation. 193 IntentFilter sdFilter = new IntentFilter(); 194 sdFilter.addAction(Intent.ACTION_EXTERNAL_APPLICATIONS_AVAILABLE); 195 sdFilter.addAction(Intent.ACTION_EXTERNAL_APPLICATIONS_UNAVAILABLE); 196 mLoader.getContext().registerReceiver(this, sdFilter); 197 } 198 199 @Override public void onReceive(Context context, Intent intent) { 200 // Tell the loader about the change. 201 mLoader.onContentChanged(); 202 } 203 } 204 205 /** 206 * A custom Loader that loads all of the installed applications. 207 */ 208 public static class AppListLoader extends AsyncTaskLoader<List<AppEntry>> { 209 final InterestingConfigChanges mLastConfig = new InterestingConfigChanges(); 210 final PackageManager mPm; 211 212 List<AppEntry> mApps; 213 PackageIntentReceiver mPackageObserver; 214 215 public AppListLoader(Context context) { 216 super(context); 217 218 // Retrieve the package manager for later use; note we don't 219 // use 'context' directly but instead the save global application 220 // context returned by getContext(). 221 mPm = getContext().getPackageManager(); 222 } 223 224 /** 225 * This is where the bulk of our work is done. This function is 226 * called in a background thread and should generate a new set of 227 * data to be published by the loader. 228 */ 229 @Override public List<AppEntry> loadInBackground() { 230 // Retrieve all known applications. 231 //noinspection WrongConstant 232 List<ApplicationInfo> apps = mPm.getInstalledApplications( 233 PackageManager.MATCH_UNINSTALLED_PACKAGES 234 | PackageManager.MATCH_DISABLED_COMPONENTS); 235 if (apps == null) { 236 apps = new ArrayList<ApplicationInfo>(); 237 } 238 239 final Context context = getContext(); 240 241 // Create corresponding array of entries and load their labels. 242 List<AppEntry> entries = new ArrayList<AppEntry>(apps.size()); 243 for (int i = 0; i < apps.size(); i++) { 244 AppEntry entry = new AppEntry(this, apps.get(i)); 245 entry.loadLabel(context); 246 entries.add(entry); 247 } 248 249 // Sort the list. 250 Collections.sort(entries, ALPHA_COMPARATOR); 251 252 // Done! 253 return entries; 254 } 255 256 /** 257 * Called when there is new data to deliver to the client. The 258 * super class will take care of delivering it; the implementation 259 * here just adds a little more logic. 260 */ 261 @Override public void deliverResult(List<AppEntry> apps) { 262 if (isReset()) { 263 // An async query came in while the loader is stopped. We 264 // don't need the result. 265 if (apps != null) { 266 onReleaseResources(apps); 267 } 268 } 269 List<AppEntry> oldApps = apps; 270 mApps = apps; 271 272 if (isStarted()) { 273 // If the Loader is currently started, we can immediately 274 // deliver its results. 275 super.deliverResult(apps); 276 } 277 278 // At this point we can release the resources associated with 279 // 'oldApps' if needed; now that the new result is delivered we 280 // know that it is no longer in use. 281 if (oldApps != null) { 282 onReleaseResources(oldApps); 283 } 284 } 285 286 /** 287 * Handles a request to start the Loader. 288 */ 289 @Override protected void onStartLoading() { 290 if (mApps != null) { 291 // If we currently have a result available, deliver it 292 // immediately. 293 deliverResult(mApps); 294 } 295 296 // Start watching for changes in the app data. 297 if (mPackageObserver == null) { 298 mPackageObserver = new PackageIntentReceiver(this); 299 } 300 301 // Has something interesting in the configuration changed since we 302 // last built the app list? 303 boolean configChange = mLastConfig.applyNewConfig(getContext().getResources()); 304 305 if (takeContentChanged() || mApps == null || configChange) { 306 // If the data has changed since the last time it was loaded 307 // or is not currently available, start a load. 308 forceLoad(); 309 } 310 } 311 312 /** 313 * Handles a request to stop the Loader. 314 */ 315 @Override protected void onStopLoading() { 316 // Attempt to cancel the current load task if possible. 317 cancelLoad(); 318 } 319 320 /** 321 * Handles a request to cancel a load. 322 */ 323 @Override public void onCanceled(List<AppEntry> apps) { 324 super.onCanceled(apps); 325 326 // At this point we can release the resources associated with 'apps' 327 // if needed. 328 onReleaseResources(apps); 329 } 330 331 /** 332 * Handles a request to completely reset the Loader. 333 */ 334 @Override protected void onReset() { 335 super.onReset(); 336 337 // Ensure the loader is stopped 338 onStopLoading(); 339 340 // At this point we can release the resources associated with 'apps' 341 // if needed. 342 if (mApps != null) { 343 onReleaseResources(mApps); 344 mApps = null; 345 } 346 347 // Stop monitoring for changes. 348 if (mPackageObserver != null) { 349 getContext().unregisterReceiver(mPackageObserver); 350 mPackageObserver = null; 351 } 352 } 353 354 /** 355 * Helper function to take care of releasing resources associated 356 * with an actively loaded data set. 357 */ 358 protected void onReleaseResources(List<AppEntry> apps) { 359 // For a simple List<> there is nothing to do. For something 360 // like a Cursor, we would close it here. 361 } 362 } 363//END_INCLUDE(loader) 364 365//BEGIN_INCLUDE(fragment) 366 public static class AppListAdapter extends ArrayAdapter<AppEntry> { 367 private final LayoutInflater mInflater; 368 369 public AppListAdapter(Context context) { 370 super(context, android.R.layout.simple_list_item_2); 371 mInflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE); 372 } 373 374 public void setData(List<AppEntry> data) { 375 clear(); 376 if (data != null) { 377 for (AppEntry appEntry : data) { 378 add(appEntry); 379 } 380 } 381 } 382 383 /** 384 * Populate new items in the list. 385 */ 386 @Override public View getView(int position, View convertView, ViewGroup parent) { 387 View view; 388 389 if (convertView == null) { 390 view = mInflater.inflate(R.layout.list_item_icon_text, parent, false); 391 } else { 392 view = convertView; 393 } 394 395 AppEntry item = getItem(position); 396 ((ImageView)view.findViewById(R.id.icon)).setImageDrawable(item.getIcon()); 397 ((TextView)view.findViewById(R.id.text)).setText(item.getLabel()); 398 399 return view; 400 } 401 } 402 403 public static class AppListFragment extends ListFragment 404 implements LoaderManager.LoaderCallbacks<List<AppEntry>> { 405 406 // This is the Adapter being used to display the list's data. 407 AppListAdapter mAdapter; 408 409 // If non-null, this is the current filter the user has provided. 410 String mCurFilter; 411 412 @Override public void onActivityCreated(Bundle savedInstanceState) { 413 super.onActivityCreated(savedInstanceState); 414 415 // Give some text to display if there is no data. In a real 416 // application this would come from a resource. 417 setEmptyText("No applications"); 418 419 // We have a menu item to show in action bar. 420 setHasOptionsMenu(true); 421 422 // Create an empty adapter we will use to display the loaded data. 423 mAdapter = new AppListAdapter(getActivity()); 424 setListAdapter(mAdapter); 425 426 // Start out with a progress indicator. 427 setListShown(false); 428 429 // Prepare the loader. Either re-connect with an existing one, 430 // or start a new one. 431 getLoaderManager().initLoader(0, null, this); 432 } 433 434 @Override public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) { 435 // Place an action bar item for searching. 436 MenuItem item = menu.add("Search"); 437 item.setIcon(android.R.drawable.ic_menu_search); 438 item.setShowAsAction(MenuItem.SHOW_AS_ACTION_IF_ROOM 439 | MenuItem.SHOW_AS_ACTION_COLLAPSE_ACTION_VIEW); 440 final SearchView searchView = new SearchView(getActivity()); 441 searchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() { 442 @Override 443 public boolean onQueryTextChange(String newText) { 444 // Called when the action bar search text has changed. Since this 445 // is a simple array adapter, we can just have it do the filtering. 446 mCurFilter = !TextUtils.isEmpty(newText) ? newText : null; 447 mAdapter.getFilter().filter(mCurFilter); 448 return true; 449 } 450 451 @Override 452 public boolean onQueryTextSubmit(String query) { 453 return false; 454 } 455 }); 456 457 searchView.setOnCloseListener(new SearchView.OnCloseListener() { 458 @Override 459 public boolean onClose() { 460 if (!TextUtils.isEmpty(searchView.getQuery())) { 461 searchView.setQuery(null, true); 462 } 463 return true; 464 } 465 }); 466 467 item.setActionView(searchView); 468 } 469 470 @Override public void onListItemClick(ListView l, View v, int position, long id) { 471 // Insert desired behavior here. 472 Log.i("LoaderCustom", "Item clicked: " + id); 473 } 474 475 @NonNull 476 @Override public Loader<List<AppEntry>> onCreateLoader(int id, Bundle args) { 477 // This is called when a new Loader needs to be created. This 478 // sample only has one Loader with no arguments, so it is simple. 479 return new AppListLoader(getActivity()); 480 } 481 482 @Override public void onLoadFinished(@NonNull Loader<List<AppEntry>> loader, 483 List<AppEntry> data) { 484 // Set the new data in the adapter. 485 mAdapter.setData(data); 486 487 // The list should now be shown. 488 if (isResumed()) { 489 setListShown(true); 490 } else { 491 setListShownNoAnimation(true); 492 } 493 } 494 495 @Override public void onLoaderReset(@NonNull Loader<List<AppEntry>> loader) { 496 // Clear the data in the adapter. 497 mAdapter.setData(null); 498 } 499 } 500//END_INCLUDE(fragment) 501} 502