1/* 2 * Copyright (C) 2009 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.app; 18 19import com.android.internal.R; 20 21import android.content.ComponentName; 22import android.content.ContentResolver; 23import android.content.Context; 24import android.content.ContentResolver.OpenResourceIdResult; 25import android.content.pm.ActivityInfo; 26import android.content.pm.PackageManager; 27import android.content.pm.PackageManager.NameNotFoundException; 28import android.content.res.ColorStateList; 29import android.content.res.Resources; 30import android.database.Cursor; 31import android.graphics.drawable.ColorDrawable; 32import android.graphics.drawable.Drawable; 33import android.graphics.drawable.StateListDrawable; 34import android.net.Uri; 35import android.os.Bundle; 36import android.text.Spannable; 37import android.text.SpannableString; 38import android.text.TextUtils; 39import android.text.style.TextAppearanceSpan; 40import android.util.Log; 41import android.util.SparseArray; 42import android.util.TypedValue; 43import android.view.View; 44import android.view.ViewGroup; 45import android.widget.Filter; 46import android.widget.ImageView; 47import android.widget.ResourceCursorAdapter; 48import android.widget.TextView; 49 50import java.io.FileNotFoundException; 51import java.io.IOException; 52import java.io.InputStream; 53import java.util.WeakHashMap; 54 55/** 56 * Provides the contents for the suggestion drop-down list.in {@link SearchDialog}. 57 * 58 * @hide 59 */ 60class SuggestionsAdapter extends ResourceCursorAdapter { 61 62 private static final boolean DBG = false; 63 private static final String LOG_TAG = "SuggestionsAdapter"; 64 private static final int QUERY_LIMIT = 50; 65 66 private SearchManager mSearchManager; 67 private SearchDialog mSearchDialog; 68 private SearchableInfo mSearchable; 69 private Context mProviderContext; 70 private WeakHashMap<String, Drawable.ConstantState> mOutsideDrawablesCache; 71 private SparseArray<Drawable.ConstantState> mBackgroundsCache; 72 private boolean mClosed = false; 73 74 // URL color 75 private ColorStateList mUrlColor; 76 77 // Cached column indexes, updated when the cursor changes. 78 private int mText1Col; 79 private int mText2Col; 80 private int mText2UrlCol; 81 private int mIconName1Col; 82 private int mIconName2Col; 83 private int mBackgroundColorCol; 84 85 static final int NONE = -1; 86 87 private final Runnable mStartSpinnerRunnable; 88 private final Runnable mStopSpinnerRunnable; 89 90 /** 91 * The amount of time we delay in the filter when the user presses the delete key. 92 * @see Filter#setDelayer(android.widget.Filter.Delayer). 93 */ 94 private static final long DELETE_KEY_POST_DELAY = 500L; 95 96 public SuggestionsAdapter(Context context, SearchDialog searchDialog, 97 SearchableInfo searchable, 98 WeakHashMap<String, Drawable.ConstantState> outsideDrawablesCache) { 99 super(context, 100 com.android.internal.R.layout.search_dropdown_item_icons_2line, 101 null, // no initial cursor 102 true); // auto-requery 103 mSearchManager = (SearchManager) mContext.getSystemService(Context.SEARCH_SERVICE); 104 mSearchDialog = searchDialog; 105 mSearchable = searchable; 106 107 // set up provider resources (gives us icons, etc.) 108 Context activityContext = mSearchable.getActivityContext(mContext); 109 mProviderContext = mSearchable.getProviderContext(mContext, activityContext); 110 111 mOutsideDrawablesCache = outsideDrawablesCache; 112 mBackgroundsCache = new SparseArray<Drawable.ConstantState>(); 113 114 mStartSpinnerRunnable = new Runnable() { 115 public void run() { 116 mSearchDialog.setWorking(true); 117 } 118 }; 119 120 mStopSpinnerRunnable = new Runnable() { 121 public void run() { 122 mSearchDialog.setWorking(false); 123 } 124 }; 125 126 // delay 500ms when deleting 127 getFilter().setDelayer(new Filter.Delayer() { 128 129 private int mPreviousLength = 0; 130 131 public long getPostingDelay(CharSequence constraint) { 132 if (constraint == null) return 0; 133 134 long delay = constraint.length() < mPreviousLength ? DELETE_KEY_POST_DELAY : 0; 135 mPreviousLength = constraint.length(); 136 return delay; 137 } 138 }); 139 } 140 141 /** 142 * Overridden to always return <code>false</code>, since we cannot be sure that 143 * suggestion sources return stable IDs. 144 */ 145 @Override 146 public boolean hasStableIds() { 147 return false; 148 } 149 150 /** 151 * Use the search suggestions provider to obtain a live cursor. This will be called 152 * in a worker thread, so it's OK if the query is slow (e.g. round trip for suggestions). 153 * The results will be processed in the UI thread and changeCursor() will be called. 154 */ 155 @Override 156 public Cursor runQueryOnBackgroundThread(CharSequence constraint) { 157 if (DBG) Log.d(LOG_TAG, "runQueryOnBackgroundThread(" + constraint + ")"); 158 String query = (constraint == null) ? "" : constraint.toString(); 159 /** 160 * for in app search we show the progress spinner until the cursor is returned with 161 * the results. 162 */ 163 Cursor cursor = null; 164 mSearchDialog.getWindow().getDecorView().post(mStartSpinnerRunnable); 165 try { 166 cursor = mSearchManager.getSuggestions(mSearchable, query, QUERY_LIMIT); 167 // trigger fill window so the spinner stays up until the results are copied over and 168 // closer to being ready 169 if (cursor != null) { 170 cursor.getCount(); 171 return cursor; 172 } 173 } catch (RuntimeException e) { 174 Log.w(LOG_TAG, "Search suggestions query threw an exception.", e); 175 } 176 // If cursor is null or an exception was thrown, stop the spinner and return null. 177 // changeCursor doesn't get called if cursor is null 178 mSearchDialog.getWindow().getDecorView().post(mStopSpinnerRunnable); 179 return null; 180 } 181 182 public void close() { 183 if (DBG) Log.d(LOG_TAG, "close()"); 184 changeCursor(null); 185 mClosed = true; 186 } 187 188 @Override 189 public void notifyDataSetChanged() { 190 if (DBG) Log.d(LOG_TAG, "notifyDataSetChanged"); 191 super.notifyDataSetChanged(); 192 193 mSearchDialog.onDataSetChanged(); 194 195 updateSpinnerState(getCursor()); 196 } 197 198 @Override 199 public void notifyDataSetInvalidated() { 200 if (DBG) Log.d(LOG_TAG, "notifyDataSetInvalidated"); 201 super.notifyDataSetInvalidated(); 202 203 updateSpinnerState(getCursor()); 204 } 205 206 private void updateSpinnerState(Cursor cursor) { 207 Bundle extras = cursor != null ? cursor.getExtras() : null; 208 if (DBG) { 209 Log.d(LOG_TAG, "updateSpinnerState - extra = " 210 + (extras != null 211 ? extras.getBoolean(SearchManager.CURSOR_EXTRA_KEY_IN_PROGRESS) 212 : null)); 213 } 214 // Check if the Cursor indicates that the query is not complete and show the spinner 215 if (extras != null 216 && extras.getBoolean(SearchManager.CURSOR_EXTRA_KEY_IN_PROGRESS)) { 217 mSearchDialog.getWindow().getDecorView().post(mStartSpinnerRunnable); 218 return; 219 } 220 // If cursor is null or is done, stop the spinner 221 mSearchDialog.getWindow().getDecorView().post(mStopSpinnerRunnable); 222 } 223 224 /** 225 * Cache columns. 226 */ 227 @Override 228 public void changeCursor(Cursor c) { 229 if (DBG) Log.d(LOG_TAG, "changeCursor(" + c + ")"); 230 231 if (mClosed) { 232 Log.w(LOG_TAG, "Tried to change cursor after adapter was closed."); 233 if (c != null) c.close(); 234 return; 235 } 236 237 try { 238 super.changeCursor(c); 239 240 if (c != null) { 241 mText1Col = c.getColumnIndex(SearchManager.SUGGEST_COLUMN_TEXT_1); 242 mText2Col = c.getColumnIndex(SearchManager.SUGGEST_COLUMN_TEXT_2); 243 mText2UrlCol = c.getColumnIndex(SearchManager.SUGGEST_COLUMN_TEXT_2_URL); 244 mIconName1Col = c.getColumnIndex(SearchManager.SUGGEST_COLUMN_ICON_1); 245 mIconName2Col = c.getColumnIndex(SearchManager.SUGGEST_COLUMN_ICON_2); 246 mBackgroundColorCol = 247 c.getColumnIndex(SearchManager.SUGGEST_COLUMN_BACKGROUND_COLOR); 248 } 249 } catch (Exception e) { 250 Log.e(LOG_TAG, "error changing cursor and caching columns", e); 251 } 252 } 253 254 /** 255 * Tags the view with cached child view look-ups. 256 */ 257 @Override 258 public View newView(Context context, Cursor cursor, ViewGroup parent) { 259 View v = super.newView(context, cursor, parent); 260 v.setTag(new ChildViewCache(v)); 261 return v; 262 } 263 264 /** 265 * Cache of the child views of drop-drown list items, to avoid looking up the children 266 * each time the contents of a list item are changed. 267 */ 268 private final static class ChildViewCache { 269 public final TextView mText1; 270 public final TextView mText2; 271 public final ImageView mIcon1; 272 public final ImageView mIcon2; 273 274 public ChildViewCache(View v) { 275 mText1 = (TextView) v.findViewById(com.android.internal.R.id.text1); 276 mText2 = (TextView) v.findViewById(com.android.internal.R.id.text2); 277 mIcon1 = (ImageView) v.findViewById(com.android.internal.R.id.icon1); 278 mIcon2 = (ImageView) v.findViewById(com.android.internal.R.id.icon2); 279 } 280 } 281 282 @Override 283 public void bindView(View view, Context context, Cursor cursor) { 284 ChildViewCache views = (ChildViewCache) view.getTag(); 285 286 int backgroundColor = 0; 287 if (mBackgroundColorCol != -1) { 288 backgroundColor = cursor.getInt(mBackgroundColorCol); 289 } 290 Drawable background = getItemBackground(backgroundColor); 291 view.setBackgroundDrawable(background); 292 293 if (views.mText1 != null) { 294 String text1 = getStringOrNull(cursor, mText1Col); 295 setViewText(views.mText1, text1); 296 } 297 if (views.mText2 != null) { 298 // First check TEXT_2_URL 299 CharSequence text2 = getStringOrNull(cursor, mText2UrlCol); 300 if (text2 != null) { 301 text2 = formatUrl(text2); 302 } else { 303 text2 = getStringOrNull(cursor, mText2Col); 304 } 305 306 // If no second line of text is indicated, allow the first line of text 307 // to be up to two lines if it wants to be. 308 if (TextUtils.isEmpty(text2)) { 309 if (views.mText1 != null) { 310 views.mText1.setSingleLine(false); 311 views.mText1.setMaxLines(2); 312 } 313 } else { 314 if (views.mText1 != null) { 315 views.mText1.setSingleLine(true); 316 views.mText1.setMaxLines(1); 317 } 318 } 319 setViewText(views.mText2, text2); 320 } 321 322 if (views.mIcon1 != null) { 323 setViewDrawable(views.mIcon1, getIcon1(cursor)); 324 } 325 if (views.mIcon2 != null) { 326 setViewDrawable(views.mIcon2, getIcon2(cursor)); 327 } 328 } 329 330 private CharSequence formatUrl(CharSequence url) { 331 if (mUrlColor == null) { 332 // Lazily get the URL color from the current theme. 333 TypedValue colorValue = new TypedValue(); 334 mContext.getTheme().resolveAttribute(R.attr.textColorSearchUrl, colorValue, true); 335 mUrlColor = mContext.getResources().getColorStateList(colorValue.resourceId); 336 } 337 338 SpannableString text = new SpannableString(url); 339 text.setSpan(new TextAppearanceSpan(null, 0, 0, mUrlColor, null), 340 0, url.length(), 341 Spannable.SPAN_EXCLUSIVE_EXCLUSIVE); 342 return text; 343 } 344 345 /** 346 * Gets a drawable with no color when selected or pressed, and the given color when 347 * neither selected nor pressed. 348 * 349 * @return A drawable, or {@code null} if the given color is transparent. 350 */ 351 private Drawable getItemBackground(int backgroundColor) { 352 if (backgroundColor == 0) { 353 return null; 354 } else { 355 Drawable.ConstantState cachedBg = mBackgroundsCache.get(backgroundColor); 356 if (cachedBg != null) { 357 if (DBG) Log.d(LOG_TAG, "Background cache hit for color " + backgroundColor); 358 return cachedBg.newDrawable(mProviderContext.getResources()); 359 } 360 if (DBG) Log.d(LOG_TAG, "Creating new background for color " + backgroundColor); 361 ColorDrawable transparent = new ColorDrawable(0); 362 ColorDrawable background = new ColorDrawable(backgroundColor); 363 StateListDrawable newBg = new StateListDrawable(); 364 newBg.addState(new int[]{android.R.attr.state_selected}, transparent); 365 newBg.addState(new int[]{android.R.attr.state_pressed}, transparent); 366 newBg.addState(new int[]{}, background); 367 mBackgroundsCache.put(backgroundColor, newBg.getConstantState()); 368 return newBg; 369 } 370 } 371 372 private void setViewText(TextView v, CharSequence text) { 373 // Set the text even if it's null, since we need to clear any previous text. 374 v.setText(text); 375 376 if (TextUtils.isEmpty(text)) { 377 v.setVisibility(View.GONE); 378 } else { 379 v.setVisibility(View.VISIBLE); 380 } 381 } 382 383 private Drawable getIcon1(Cursor cursor) { 384 if (mIconName1Col < 0) { 385 return null; 386 } 387 String value = cursor.getString(mIconName1Col); 388 Drawable drawable = getDrawableFromResourceValue(value); 389 if (drawable != null) { 390 return drawable; 391 } 392 return getDefaultIcon1(cursor); 393 } 394 395 private Drawable getIcon2(Cursor cursor) { 396 if (mIconName2Col < 0) { 397 return null; 398 } 399 String value = cursor.getString(mIconName2Col); 400 return getDrawableFromResourceValue(value); 401 } 402 403 /** 404 * Sets the drawable in an image view, makes sure the view is only visible if there 405 * is a drawable. 406 */ 407 private void setViewDrawable(ImageView v, Drawable drawable) { 408 // Set the icon even if the drawable is null, since we need to clear any 409 // previous icon. 410 v.setImageDrawable(drawable); 411 412 if (drawable == null) { 413 v.setVisibility(View.GONE); 414 } else { 415 v.setVisibility(View.VISIBLE); 416 417 // This is a hack to get any animated drawables (like a 'working' spinner) 418 // to animate. You have to setVisible true on an AnimationDrawable to get 419 // it to start animating, but it must first have been false or else the 420 // call to setVisible will be ineffective. We need to clear up the story 421 // about animated drawables in the future, see http://b/1878430. 422 drawable.setVisible(false, false); 423 drawable.setVisible(true, false); 424 } 425 } 426 427 /** 428 * Gets the text to show in the query field when a suggestion is selected. 429 * 430 * @param cursor The Cursor to read the suggestion data from. The Cursor should already 431 * be moved to the suggestion that is to be read from. 432 * @return The text to show, or <code>null</code> if the query should not be 433 * changed when selecting this suggestion. 434 */ 435 @Override 436 public CharSequence convertToString(Cursor cursor) { 437 if (cursor == null) { 438 return null; 439 } 440 441 String query = getColumnString(cursor, SearchManager.SUGGEST_COLUMN_QUERY); 442 if (query != null) { 443 return query; 444 } 445 446 if (mSearchable.shouldRewriteQueryFromData()) { 447 String data = getColumnString(cursor, SearchManager.SUGGEST_COLUMN_INTENT_DATA); 448 if (data != null) { 449 return data; 450 } 451 } 452 453 if (mSearchable.shouldRewriteQueryFromText()) { 454 String text1 = getColumnString(cursor, SearchManager.SUGGEST_COLUMN_TEXT_1); 455 if (text1 != null) { 456 return text1; 457 } 458 } 459 460 return null; 461 } 462 463 /** 464 * This method is overridden purely to provide a bit of protection against 465 * flaky content providers. 466 * 467 * @see android.widget.ListAdapter#getView(int, View, ViewGroup) 468 */ 469 @Override 470 public View getView(int position, View convertView, ViewGroup parent) { 471 try { 472 return super.getView(position, convertView, parent); 473 } catch (RuntimeException e) { 474 Log.w(LOG_TAG, "Search suggestions cursor threw exception.", e); 475 // Put exception string in item title 476 View v = newView(mContext, mCursor, parent); 477 if (v != null) { 478 ChildViewCache views = (ChildViewCache) v.getTag(); 479 TextView tv = views.mText1; 480 tv.setText(e.toString()); 481 } 482 return v; 483 } 484 } 485 486 /** 487 * Gets a drawable given a value provided by a suggestion provider. 488 * 489 * This value could be just the string value of a resource id 490 * (e.g., "2130837524"), in which case we will try to retrieve a drawable from 491 * the provider's resources. If the value is not an integer, it is 492 * treated as a Uri and opened with 493 * {@link ContentResolver#openOutputStream(android.net.Uri, String)}. 494 * 495 * All resources and URIs are read using the suggestion provider's context. 496 * 497 * If the string is not formatted as expected, or no drawable can be found for 498 * the provided value, this method returns null. 499 * 500 * @param drawableId a string like "2130837524", 501 * "android.resource://com.android.alarmclock/2130837524", 502 * or "content://contacts/photos/253". 503 * @return a Drawable, or null if none found 504 */ 505 private Drawable getDrawableFromResourceValue(String drawableId) { 506 if (drawableId == null || drawableId.length() == 0 || "0".equals(drawableId)) { 507 return null; 508 } 509 try { 510 // First, see if it's just an integer 511 int resourceId = Integer.parseInt(drawableId); 512 // It's an int, look for it in the cache 513 String drawableUri = ContentResolver.SCHEME_ANDROID_RESOURCE 514 + "://" + mProviderContext.getPackageName() + "/" + resourceId; 515 // Must use URI as cache key, since ints are app-specific 516 Drawable drawable = checkIconCache(drawableUri); 517 if (drawable != null) { 518 return drawable; 519 } 520 // Not cached, find it by resource ID 521 drawable = mProviderContext.getResources().getDrawable(resourceId); 522 // Stick it in the cache, using the URI as key 523 storeInIconCache(drawableUri, drawable); 524 return drawable; 525 } catch (NumberFormatException nfe) { 526 // It's not an integer, use it as a URI 527 Drawable drawable = checkIconCache(drawableId); 528 if (drawable != null) { 529 return drawable; 530 } 531 Uri uri = Uri.parse(drawableId); 532 drawable = getDrawable(uri); 533 storeInIconCache(drawableId, drawable); 534 return drawable; 535 } catch (Resources.NotFoundException nfe) { 536 // It was an integer, but it couldn't be found, bail out 537 Log.w(LOG_TAG, "Icon resource not found: " + drawableId); 538 return null; 539 } 540 } 541 542 /** 543 * Gets a drawable by URI, without using the cache. 544 * 545 * @return A drawable, or {@code null} if the drawable could not be loaded. 546 */ 547 private Drawable getDrawable(Uri uri) { 548 try { 549 String scheme = uri.getScheme(); 550 if (ContentResolver.SCHEME_ANDROID_RESOURCE.equals(scheme)) { 551 // Load drawables through Resources, to get the source density information 552 OpenResourceIdResult r = 553 mProviderContext.getContentResolver().getResourceId(uri); 554 try { 555 return r.r.getDrawable(r.id); 556 } catch (Resources.NotFoundException ex) { 557 throw new FileNotFoundException("Resource does not exist: " + uri); 558 } 559 } else { 560 // Let the ContentResolver handle content and file URIs. 561 InputStream stream = mProviderContext.getContentResolver().openInputStream(uri); 562 if (stream == null) { 563 throw new FileNotFoundException("Failed to open " + uri); 564 } 565 try { 566 return Drawable.createFromStream(stream, null); 567 } finally { 568 try { 569 stream.close(); 570 } catch (IOException ex) { 571 Log.e(LOG_TAG, "Error closing icon stream for " + uri, ex); 572 } 573 } 574 } 575 } catch (FileNotFoundException fnfe) { 576 Log.w(LOG_TAG, "Icon not found: " + uri + ", " + fnfe.getMessage()); 577 return null; 578 } 579 } 580 581 private Drawable checkIconCache(String resourceUri) { 582 Drawable.ConstantState cached = mOutsideDrawablesCache.get(resourceUri); 583 if (cached == null) { 584 return null; 585 } 586 if (DBG) Log.d(LOG_TAG, "Found icon in cache: " + resourceUri); 587 return cached.newDrawable(); 588 } 589 590 private void storeInIconCache(String resourceUri, Drawable drawable) { 591 if (drawable != null) { 592 mOutsideDrawablesCache.put(resourceUri, drawable.getConstantState()); 593 } 594 } 595 596 /** 597 * Gets the left-hand side icon that will be used for the current suggestion 598 * if the suggestion contains an icon column but no icon or a broken icon. 599 * 600 * @param cursor A cursor positioned at the current suggestion. 601 * @return A non-null drawable. 602 */ 603 private Drawable getDefaultIcon1(Cursor cursor) { 604 // First check the component that the suggestion is originally from 605 String c = getColumnString(cursor, SearchManager.SUGGEST_COLUMN_INTENT_COMPONENT_NAME); 606 if (c != null) { 607 ComponentName component = ComponentName.unflattenFromString(c); 608 if (component != null) { 609 Drawable drawable = getActivityIconWithCache(component); 610 if (drawable != null) { 611 return drawable; 612 } 613 } else { 614 Log.w(LOG_TAG, "Bad component name: " + c); 615 } 616 } 617 618 // Then check the component that gave us the suggestion 619 Drawable drawable = getActivityIconWithCache(mSearchable.getSearchActivity()); 620 if (drawable != null) { 621 return drawable; 622 } 623 624 // Fall back to a default icon 625 return mContext.getPackageManager().getDefaultActivityIcon(); 626 } 627 628 /** 629 * Gets the activity or application icon for an activity. 630 * Uses the local icon cache for fast repeated lookups. 631 * 632 * @param component Name of an activity. 633 * @return A drawable, or {@code null} if neither the activity nor the application 634 * has an icon set. 635 */ 636 private Drawable getActivityIconWithCache(ComponentName component) { 637 // First check the icon cache 638 String componentIconKey = component.flattenToShortString(); 639 // Using containsKey() since we also store null values. 640 if (mOutsideDrawablesCache.containsKey(componentIconKey)) { 641 Drawable.ConstantState cached = mOutsideDrawablesCache.get(componentIconKey); 642 return cached == null ? null : cached.newDrawable(mProviderContext.getResources()); 643 } 644 // Then try the activity or application icon 645 Drawable drawable = getActivityIcon(component); 646 // Stick it in the cache so we don't do this lookup again. 647 Drawable.ConstantState toCache = drawable == null ? null : drawable.getConstantState(); 648 mOutsideDrawablesCache.put(componentIconKey, toCache); 649 return drawable; 650 } 651 652 /** 653 * Gets the activity or application icon for an activity. 654 * 655 * @param component Name of an activity. 656 * @return A drawable, or {@code null} if neither the acitivy or the application 657 * have an icon set. 658 */ 659 private Drawable getActivityIcon(ComponentName component) { 660 PackageManager pm = mContext.getPackageManager(); 661 final ActivityInfo activityInfo; 662 try { 663 activityInfo = pm.getActivityInfo(component, PackageManager.GET_META_DATA); 664 } catch (NameNotFoundException ex) { 665 Log.w(LOG_TAG, ex.toString()); 666 return null; 667 } 668 int iconId = activityInfo.getIconResource(); 669 if (iconId == 0) return null; 670 String pkg = component.getPackageName(); 671 Drawable drawable = pm.getDrawable(pkg, iconId, activityInfo.applicationInfo); 672 if (drawable == null) { 673 Log.w(LOG_TAG, "Invalid icon resource " + iconId + " for " 674 + component.flattenToShortString()); 675 return null; 676 } 677 return drawable; 678 } 679 680 /** 681 * Gets the value of a string column by name. 682 * 683 * @param cursor Cursor to read the value from. 684 * @param columnName The name of the column to read. 685 * @return The value of the given column, or <code>null</null> 686 * if the cursor does not contain the given column. 687 */ 688 public static String getColumnString(Cursor cursor, String columnName) { 689 int col = cursor.getColumnIndex(columnName); 690 return getStringOrNull(cursor, col); 691 } 692 693 private static String getStringOrNull(Cursor cursor, int col) { 694 if (col == NONE) { 695 return null; 696 } 697 try { 698 return cursor.getString(col); 699 } catch (Exception e) { 700 Log.e(LOG_TAG, 701 "unexpected error retrieving valid column from cursor, " 702 + "did the remote process die?", e); 703 return null; 704 } 705 } 706} 707