1/* 2 * Copyright (C) 2012 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 android.support.v4.app; 18 19import android.app.Activity; 20import android.app.PendingIntent; 21import android.content.ComponentName; 22import android.content.Context; 23import android.content.Intent; 24import android.content.pm.PackageManager.NameNotFoundException; 25import android.os.Build; 26import android.os.Bundle; 27import android.support.v4.content.ContextCompat; 28import android.support.v4.content.IntentCompat; 29import android.util.Log; 30 31import java.util.ArrayList; 32import java.util.Iterator; 33 34/** 35 * Utility class for constructing synthetic back stacks for cross-task navigation 36 * on Android 3.0 and newer. 37 * 38 * <p>In API level 11 (Android 3.0/Honeycomb) the recommended conventions for 39 * app navigation using the back key changed. The back key's behavior is local 40 * to the current task and does not capture navigation across different tasks. 41 * Navigating across tasks and easily reaching the previous task is accomplished 42 * through the "recents" UI, accessible through the software-provided Recents key 43 * on the navigation or system bar. On devices with the older hardware button configuration 44 * the recents UI can be accessed with a long press on the Home key.</p> 45 * 46 * <p>When crossing from one task stack to another post-Android 3.0, 47 * the application should synthesize a back stack/history for the new task so that 48 * the user may navigate out of the new task and back to the Launcher by repeated 49 * presses of the back key. Back key presses should not navigate across task stacks.</p> 50 * 51 * <p>TaskStackBuilder provides a backward-compatible way to obey the correct conventions 52 * around cross-task navigation on the device's version of the platform. On devices running 53 * Android 3.0 or newer, calls to the {@link #startActivities()} method or sending the 54 * {@link PendingIntent} generated by {@link #getPendingIntent(int, int)} will construct 55 * the synthetic back stack as prescribed. On devices running older versions of the platform, 56 * these same calls will invoke the topmost activity in the supplied stack, ignoring 57 * the rest of the synthetic stack and allowing the back key to navigate back to the previous 58 * task.</p> 59 * 60 * <div class="special reference"> 61 * <h3>About Navigation</h3> 62 * For more detailed information about tasks, the back stack, and navigation design guidelines, 63 * please read 64 * <a href="{@docRoot}guide/topics/fundamentals/tasks-and-back-stack.html">Tasks and Back Stack</a> 65 * from the developer guide and <a href="{@docRoot}design/patterns/navigation.html">Navigation</a> 66 * from the design guide. 67 * </div> 68 */ 69public class TaskStackBuilder implements Iterable<Intent> { 70 private static final String TAG = "TaskStackBuilder"; 71 72 interface TaskStackBuilderImpl { 73 PendingIntent getPendingIntent(Context context, Intent[] intents, int requestCode, 74 int flags, Bundle options); 75 } 76 77 static class TaskStackBuilderImplBase implements TaskStackBuilderImpl { 78 public PendingIntent getPendingIntent(Context context, Intent[] intents, int requestCode, 79 int flags, Bundle options) { 80 Intent topIntent = new Intent(intents[intents.length - 1]); 81 topIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK); 82 return PendingIntent.getActivity(context, requestCode, topIntent, flags); 83 } 84 } 85 86 static class TaskStackBuilderImplHoneycomb implements TaskStackBuilderImpl { 87 public PendingIntent getPendingIntent(Context context, Intent[] intents, int requestCode, 88 int flags, Bundle options) { 89 intents[0] = new Intent(intents[0]).addFlags(Intent.FLAG_ACTIVITY_NEW_TASK | 90 IntentCompat.FLAG_ACTIVITY_CLEAR_TASK | 91 IntentCompat.FLAG_ACTIVITY_TASK_ON_HOME); 92 return TaskStackBuilderHoneycomb.getActivitiesPendingIntent(context, requestCode, 93 intents, flags); 94 } 95 } 96 97 static class TaskStackBuilderImplJellybean implements TaskStackBuilderImpl { 98 public PendingIntent getPendingIntent(Context context, Intent[] intents, int requestCode, 99 int flags, Bundle options) { 100 intents[0] = new Intent(intents[0]).addFlags(Intent.FLAG_ACTIVITY_NEW_TASK | 101 IntentCompat.FLAG_ACTIVITY_CLEAR_TASK | 102 IntentCompat.FLAG_ACTIVITY_TASK_ON_HOME); 103 return TaskStackBuilderJellybean.getActivitiesPendingIntent(context, requestCode, 104 intents, flags, options); 105 } 106 } 107 108 private static final TaskStackBuilderImpl IMPL; 109 110 static { 111 if (Build.VERSION.SDK_INT >= 11) { 112 IMPL = new TaskStackBuilderImplHoneycomb(); 113 } else { 114 IMPL = new TaskStackBuilderImplBase(); 115 } 116 } 117 118 private final ArrayList<Intent> mIntents = new ArrayList<Intent>(); 119 private final Context mSourceContext; 120 121 private TaskStackBuilder(Context a) { 122 mSourceContext = a; 123 } 124 125 /** 126 * Return a new TaskStackBuilder for launching a fresh task stack consisting 127 * of a series of activities. 128 * 129 * @param context The context that will launch the new task stack or generate a PendingIntent 130 * @return A new TaskStackBuilder 131 */ 132 public static TaskStackBuilder create(Context context) { 133 return new TaskStackBuilder(context); 134 } 135 136 /** 137 * Return a new TaskStackBuilder for launching a fresh task stack consisting 138 * of a series of activities. 139 * 140 * @param context The context that will launch the new task stack or generate a PendingIntent 141 * @return A new TaskStackBuilder 142 * 143 * @deprecated use {@link #create(Context)} instead 144 */ 145 public static TaskStackBuilder from(Context context) { 146 return create(context); 147 } 148 149 /** 150 * Add a new Intent to the task stack. The most recently added Intent will invoke 151 * the Activity at the top of the final task stack. 152 * 153 * @param nextIntent Intent for the next Activity in the synthesized task stack 154 * @return This TaskStackBuilder for method chaining 155 */ 156 public TaskStackBuilder addNextIntent(Intent nextIntent) { 157 mIntents.add(nextIntent); 158 return this; 159 } 160 161 /** 162 * Add a new Intent with the resolved chain of parents for the target activity to 163 * the task stack. 164 * 165 * <p>This is equivalent to calling {@link #addParentStack(ComponentName) addParentStack} 166 * with the resolved ComponentName of nextIntent (if it can be resolved), followed by 167 * {@link #addNextIntent(Intent) addNextIntent} with nextIntent.</p> 168 * 169 * @param nextIntent Intent for the topmost Activity in the synthesized task stack. 170 * Its chain of parents as specified in the manifest will be added. 171 * @return This TaskStackBuilder for method chaining. 172 */ 173 public TaskStackBuilder addNextIntentWithParentStack(Intent nextIntent) { 174 ComponentName target = nextIntent.getComponent(); 175 if (target == null) { 176 target = nextIntent.resolveActivity(mSourceContext.getPackageManager()); 177 } 178 if (target != null) { 179 addParentStack(target); 180 } 181 addNextIntent(nextIntent); 182 return this; 183 } 184 185 /** 186 * Add the activity parent chain as specified by manifest <meta-data> elements 187 * to the task stack builder. 188 * 189 * @param sourceActivity All parents of this activity will be added 190 * @return This TaskStackBuilder for method chaining 191 */ 192 public TaskStackBuilder addParentStack(Activity sourceActivity) { 193 final Intent parent = NavUtils.getParentActivityIntent(sourceActivity); 194 if (parent != null) { 195 // We have the actual parent intent, build the rest from static metadata 196 // then add the direct parent intent to the end. 197 ComponentName target = parent.getComponent(); 198 if (target == null) { 199 target = parent.resolveActivity(mSourceContext.getPackageManager()); 200 } 201 addParentStack(target); 202 addNextIntent(parent); 203 } 204 return this; 205 } 206 207 /** 208 * Add the activity parent chain as specified by manifest <meta-data> elements 209 * to the task stack builder. 210 * 211 * @param sourceActivityClass All parents of this activity will be added 212 * @return This TaskStackBuilder for method chaining 213 */ 214 public TaskStackBuilder addParentStack(Class<?> sourceActivityClass) { 215 return addParentStack(new ComponentName(mSourceContext, sourceActivityClass)); 216 } 217 218 /** 219 * Add the activity parent chain as specified by manifest <meta-data> elements 220 * to the task stack builder. 221 * 222 * @param sourceActivityName Must specify an Activity component. All parents of 223 * this activity will be added 224 * @return This TaskStackBuilder for method chaining 225 */ 226 public TaskStackBuilder addParentStack(ComponentName sourceActivityName) { 227 final int insertAt = mIntents.size(); 228 try { 229 Intent parent = NavUtils.getParentActivityIntent(mSourceContext, sourceActivityName); 230 while (parent != null) { 231 mIntents.add(insertAt, parent); 232 parent = NavUtils.getParentActivityIntent(mSourceContext, parent.getComponent()); 233 } 234 } catch (NameNotFoundException e) { 235 Log.e(TAG, "Bad ComponentName while traversing activity parent metadata"); 236 throw new IllegalArgumentException(e); 237 } 238 return this; 239 } 240 241 /** 242 * @return the number of intents added so far. 243 */ 244 public int getIntentCount() { 245 return mIntents.size(); 246 } 247 248 /** 249 * Get the intent at the specified index. 250 * Useful if you need to modify the flags or extras of an intent that was previously added, 251 * for example with {@link #addParentStack(Activity)}. 252 * 253 * @param index Index from 0-getIntentCount() 254 * @return the intent at position index 255 * 256 * @deprecated Renamed to editIntentAt to better reflect intended usage 257 */ 258 public Intent getIntent(int index) { 259 return editIntentAt(index); 260 } 261 262 /** 263 * Return the intent at the specified index for modification. 264 * Useful if you need to modify the flags or extras of an intent that was previously added, 265 * for example with {@link #addParentStack(Activity)}. 266 * 267 * @param index Index from 0-getIntentCount() 268 * @return the intent at position index 269 */ 270 public Intent editIntentAt(int index) { 271 return mIntents.get(index); 272 } 273 274 /** 275 * @deprecated Use editIntentAt instead 276 */ 277 public Iterator<Intent> iterator() { 278 return mIntents.iterator(); 279 } 280 281 /** 282 * Start the task stack constructed by this builder. The Context used to obtain 283 * this builder must be an Activity. 284 * 285 * <p>On devices that do not support API level 11 or higher the topmost activity 286 * will be started as a new task. On devices that do support API level 11 or higher 287 * the new task stack will be created in its entirety.</p> 288 */ 289 public void startActivities() { 290 startActivities(null); 291 } 292 293 /** 294 * Start the task stack constructed by this builder. The Context used to obtain 295 * this builder must be an Activity. 296 * 297 * <p>On devices that do not support API level 11 or higher the topmost activity 298 * will be started as a new task. On devices that do support API level 11 or higher 299 * the new task stack will be created in its entirety.</p> 300 * 301 * @param options Additional options for how the Activity should be started. 302 * See {@link android.content.Context#startActivity(Intent, Bundle) 303 */ 304 public void startActivities(Bundle options) { 305 if (mIntents.isEmpty()) { 306 throw new IllegalStateException( 307 "No intents added to TaskStackBuilder; cannot startActivities"); 308 } 309 310 Intent[] intents = mIntents.toArray(new Intent[mIntents.size()]); 311 intents[0] = new Intent(intents[0]).addFlags(Intent.FLAG_ACTIVITY_NEW_TASK | 312 IntentCompat.FLAG_ACTIVITY_CLEAR_TASK | 313 IntentCompat.FLAG_ACTIVITY_TASK_ON_HOME); 314 if (!ContextCompat.startActivities(mSourceContext, intents, options)) { 315 Intent topIntent = new Intent(intents[intents.length - 1]); 316 topIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK); 317 mSourceContext.startActivity(topIntent); 318 } 319 } 320 321 /** 322 * Obtain a {@link PendingIntent} for launching the task constructed by this builder so far. 323 * 324 * @param requestCode Private request code for the sender 325 * @param flags May be {@link PendingIntent#FLAG_ONE_SHOT}, 326 * {@link PendingIntent#FLAG_NO_CREATE}, {@link PendingIntent#FLAG_CANCEL_CURRENT}, 327 * {@link PendingIntent#FLAG_UPDATE_CURRENT}, or any of the flags supported by 328 * {@link Intent#fillIn(Intent, int)} to control which unspecified parts of the 329 * intent that can be supplied when the actual send happens. 330 * @return The obtained PendingIntent 331 */ 332 public PendingIntent getPendingIntent(int requestCode, int flags) { 333 return getPendingIntent(requestCode, flags, null); 334 } 335 336 /** 337 * Obtain a {@link PendingIntent} for launching the task constructed by this builder so far. 338 * 339 * @param requestCode Private request code for the sender 340 * @param flags May be {@link PendingIntent#FLAG_ONE_SHOT}, 341 * {@link PendingIntent#FLAG_NO_CREATE}, {@link PendingIntent#FLAG_CANCEL_CURRENT}, 342 * {@link PendingIntent#FLAG_UPDATE_CURRENT}, or any of the flags supported by 343 * {@link Intent#fillIn(Intent, int)} to control which unspecified parts of the 344 * intent that can be supplied when the actual send happens. 345 * @param options Additional options for how the Activity should be started. 346 * See {@link android.content.Context#startActivity(Intent, Bundle) 347 * @return The obtained PendingIntent 348 */ 349 public PendingIntent getPendingIntent(int requestCode, int flags, Bundle options) { 350 if (mIntents.isEmpty()) { 351 throw new IllegalStateException( 352 "No intents added to TaskStackBuilder; cannot getPendingIntent"); 353 } 354 355 Intent[] intents = mIntents.toArray(new Intent[mIntents.size()]); 356 intents[0] = new Intent(intents[0]).addFlags(Intent.FLAG_ACTIVITY_NEW_TASK | 357 IntentCompat.FLAG_ACTIVITY_CLEAR_TASK | 358 IntentCompat.FLAG_ACTIVITY_TASK_ON_HOME); 359 // Appropriate flags will be added by the call below. 360 return IMPL.getPendingIntent(mSourceContext, intents, requestCode, flags, options); 361 } 362 363 /** 364 * Return an array containing the intents added to this builder. The intent at the 365 * root of the task stack will appear as the first item in the array and the 366 * intent at the top of the stack will appear as the last item. 367 * 368 * @return An array containing the intents added to this builder. 369 */ 370 public Intent[] getIntents() { 371 Intent[] intents = new Intent[mIntents.size()]; 372 if (intents.length == 0) return intents; 373 374 intents[0] = new Intent(mIntents.get(0)).addFlags(Intent.FLAG_ACTIVITY_NEW_TASK | 375 IntentCompat.FLAG_ACTIVITY_CLEAR_TASK | 376 IntentCompat.FLAG_ACTIVITY_TASK_ON_HOME); 377 for (int i = 1; i < intents.length; i++) { 378 intents[i] = new Intent(mIntents.get(i)); 379 } 380 return intents; 381 } 382} 383