1 /*
2  * Copyright (C) 2008 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 
17 package com.android.launcher3;
18 
19 import android.app.WallpaperManager;
20 import android.content.ComponentName;
21 import android.content.Context;
22 import android.content.Intent;
23 import android.content.SharedPreferences;
24 import android.content.pm.ApplicationInfo;
25 import android.content.pm.PackageInfo;
26 import android.content.pm.PackageManager;
27 import android.content.pm.PackageManager.NameNotFoundException;
28 import android.content.pm.ResolveInfo;
29 import android.content.res.Resources;
30 import android.graphics.Bitmap;
31 import android.graphics.Color;
32 import android.graphics.Matrix;
33 import android.graphics.Paint;
34 import android.graphics.Rect;
35 import android.os.Build;
36 import android.os.Bundle;
37 import android.os.DeadObjectException;
38 import android.os.PowerManager;
39 import android.os.TransactionTooLargeException;
40 import android.support.v4.os.BuildCompat;
41 import android.text.Spannable;
42 import android.text.SpannableString;
43 import android.text.TextUtils;
44 import android.text.style.TtsSpan;
45 import android.util.DisplayMetrics;
46 import android.util.Log;
47 import android.util.Pair;
48 import android.util.SparseArray;
49 import android.util.TypedValue;
50 import android.view.View;
51 import android.view.accessibility.AccessibilityEvent;
52 import android.view.accessibility.AccessibilityManager;
53 
54 import com.android.launcher3.config.ProviderConfig;
55 
56 import java.io.ByteArrayOutputStream;
57 import java.io.Closeable;
58 import java.io.IOException;
59 import java.lang.reflect.InvocationTargetException;
60 import java.lang.reflect.Method;
61 import java.util.Collection;
62 import java.util.HashSet;
63 import java.util.Locale;
64 import java.util.concurrent.Executor;
65 import java.util.concurrent.LinkedBlockingQueue;
66 import java.util.concurrent.ThreadPoolExecutor;
67 import java.util.concurrent.TimeUnit;
68 import java.util.regex.Matcher;
69 import java.util.regex.Pattern;
70 
71 /**
72  * Various utilities shared amongst the Launcher's classes.
73  */
74 public final class Utilities {
75 
76     private static final String TAG = "Launcher.Utilities";
77 
78     private static final Pattern sTrimPattern =
79             Pattern.compile("^[\\s|\\p{javaSpaceChar}]*(.*)[\\s|\\p{javaSpaceChar}]*$");
80 
81     private static final int[] sLoc0 = new int[2];
82     private static final int[] sLoc1 = new int[2];
83     private static final float[] sPoint = new float[2];
84     private static final Matrix sMatrix = new Matrix();
85     private static final Matrix sInverseMatrix = new Matrix();
86 
isAtLeastO()87     public static boolean isAtLeastO() {
88         return BuildCompat.isAtLeastO();
89     }
90 
91     public static final boolean ATLEAST_NOUGAT_MR1 =
92         Build.VERSION.SDK_INT >= Build.VERSION_CODES.N_MR1;
93 
94     public static final boolean ATLEAST_NOUGAT =
95         Build.VERSION.SDK_INT >= Build.VERSION_CODES.N;
96 
97     public static final boolean ATLEAST_MARSHMALLOW =
98             Build.VERSION.SDK_INT >= Build.VERSION_CODES.M;
99 
100     public static final boolean ATLEAST_LOLLIPOP_MR1 =
101             Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP_MR1;
102 
103     /**
104      * Indicates if the device has a debug build. Should only be used to store additional info or
105      * add extra logging and not for changing the app behavior.
106      */
107     public static final boolean IS_DEBUG_DEVICE = Build.TYPE.toLowerCase().contains("debug");
108 
109     // An intent extra to indicate the horizontal scroll of the wallpaper.
110     public static final String EXTRA_WALLPAPER_OFFSET = "com.android.launcher3.WALLPAPER_OFFSET";
111 
112     public static final int COLOR_EXTRACTION_JOB_ID = 1;
113 
114     // These values are same as that in {@link AsyncTask}.
115     private static final int CPU_COUNT = Runtime.getRuntime().availableProcessors();
116     private static final int CORE_POOL_SIZE = CPU_COUNT + 1;
117     private static final int MAXIMUM_POOL_SIZE = CPU_COUNT * 2 + 1;
118     private static final int KEEP_ALIVE = 1;
119     /**
120      * An {@link Executor} to be used with async task with no limit on the queue size.
121      */
122     public static final Executor THREAD_POOL_EXECUTOR = new ThreadPoolExecutor(
123             CORE_POOL_SIZE, MAXIMUM_POOL_SIZE, KEEP_ALIVE,
124             TimeUnit.SECONDS, new LinkedBlockingQueue<Runnable>());
125 
126     public static final String ALLOW_ROTATION_PREFERENCE_KEY = "pref_allowRotation";
127 
isPropertyEnabled(String propertyName)128     public static boolean isPropertyEnabled(String propertyName) {
129         return Log.isLoggable(propertyName, Log.VERBOSE);
130     }
131 
isAllowRotationPrefEnabled(Context context)132     public static boolean isAllowRotationPrefEnabled(Context context) {
133         return getPrefs(context).getBoolean(ALLOW_ROTATION_PREFERENCE_KEY,
134                 getAllowRotationDefaultValue(context));
135     }
136 
getAllowRotationDefaultValue(Context context)137     public static boolean getAllowRotationDefaultValue(Context context) {
138         if (ATLEAST_NOUGAT) {
139             // If the device was scaled, used the original dimensions to determine if rotation
140             // is allowed of not.
141             Resources res = context.getResources();
142             int originalSmallestWidth = res.getConfiguration().smallestScreenWidthDp
143                     * res.getDisplayMetrics().densityDpi / DisplayMetrics.DENSITY_DEVICE_STABLE;
144             return originalSmallestWidth >= 600;
145         }
146         return false;
147     }
148 
149     /**
150      * Given a coordinate relative to the descendant, find the coordinate in a parent view's
151      * coordinates.
152      *
153      * @param descendant The descendant to which the passed coordinate is relative.
154      * @param ancestor The root view to make the coordinates relative to.
155      * @param coord The coordinate that we want mapped.
156      * @param includeRootScroll Whether or not to account for the scroll of the descendant:
157      *          sometimes this is relevant as in a child's coordinates within the descendant.
158      * @return The factor by which this descendant is scaled relative to this DragLayer. Caution
159      *         this scale factor is assumed to be equal in X and Y, and so if at any point this
160      *         assumption fails, we will need to return a pair of scale factors.
161      */
getDescendantCoordRelativeToAncestor( View descendant, View ancestor, int[] coord, boolean includeRootScroll)162     public static float getDescendantCoordRelativeToAncestor(
163             View descendant, View ancestor, int[] coord, boolean includeRootScroll) {
164         sPoint[0] = coord[0];
165         sPoint[1] = coord[1];
166 
167         float scale = 1.0f;
168         View v = descendant;
169         while(v != ancestor && v != null) {
170             // For TextViews, scroll has a meaning which relates to the text position
171             // which is very strange... ignore the scroll.
172             if (v != descendant || includeRootScroll) {
173                 sPoint[0] -= v.getScrollX();
174                 sPoint[1] -= v.getScrollY();
175             }
176 
177             v.getMatrix().mapPoints(sPoint);
178             sPoint[0] += v.getLeft();
179             sPoint[1] += v.getTop();
180             scale *= v.getScaleX();
181 
182             v = (View) v.getParent();
183         }
184 
185         coord[0] = Math.round(sPoint[0]);
186         coord[1] = Math.round(sPoint[1]);
187         return scale;
188     }
189 
190     /**
191      * Inverse of {@link #getDescendantCoordRelativeToAncestor(View, View, int[], boolean)}.
192      */
mapCoordInSelfToDescendant(View descendant, View root, int[] coord)193     public static void mapCoordInSelfToDescendant(View descendant, View root, int[] coord) {
194         sMatrix.reset();
195         View v = descendant;
196         while(v != root) {
197             sMatrix.postTranslate(-v.getScrollX(), -v.getScrollY());
198             sMatrix.postConcat(v.getMatrix());
199             sMatrix.postTranslate(v.getLeft(), v.getTop());
200             v = (View) v.getParent();
201         }
202         sMatrix.postTranslate(-v.getScrollX(), -v.getScrollY());
203         sMatrix.invert(sInverseMatrix);
204 
205         sPoint[0] = coord[0];
206         sPoint[1] = coord[1];
207         sInverseMatrix.mapPoints(sPoint);
208         coord[0] = Math.round(sPoint[0]);
209         coord[1] = Math.round(sPoint[1]);
210     }
211 
212     /**
213      * Utility method to determine whether the given point, in local coordinates,
214      * is inside the view, where the area of the view is expanded by the slop factor.
215      * This method is called while processing touch-move events to determine if the event
216      * is still within the view.
217      */
pointInView(View v, float localX, float localY, float slop)218     public static boolean pointInView(View v, float localX, float localY, float slop) {
219         return localX >= -slop && localY >= -slop && localX < (v.getWidth() + slop) &&
220                 localY < (v.getHeight() + slop);
221     }
222 
getCenterDeltaInScreenSpace(View v0, View v1)223     public static int[] getCenterDeltaInScreenSpace(View v0, View v1) {
224         v0.getLocationInWindow(sLoc0);
225         v1.getLocationInWindow(sLoc1);
226 
227         sLoc0[0] += (v0.getMeasuredWidth() * v0.getScaleX()) / 2;
228         sLoc0[1] += (v0.getMeasuredHeight() * v0.getScaleY()) / 2;
229         sLoc1[0] += (v1.getMeasuredWidth() * v1.getScaleX()) / 2;
230         sLoc1[1] += (v1.getMeasuredHeight() * v1.getScaleY()) / 2;
231         return new int[] {sLoc1[0] - sLoc0[0], sLoc1[1] - sLoc0[1]};
232     }
233 
scaleRectAboutCenter(Rect r, float scale)234     public static void scaleRectAboutCenter(Rect r, float scale) {
235         if (scale != 1.0f) {
236             int cx = r.centerX();
237             int cy = r.centerY();
238             r.offset(-cx, -cy);
239 
240             r.left = (int) (r.left * scale + 0.5f);
241             r.top = (int) (r.top * scale + 0.5f);
242             r.right = (int) (r.right * scale + 0.5f);
243             r.bottom = (int) (r.bottom * scale + 0.5f);
244 
245             r.offset(cx, cy);
246         }
247     }
248 
shrinkRect(Rect r, float scaleX, float scaleY)249     public static float shrinkRect(Rect r, float scaleX, float scaleY) {
250         float scale = Math.min(Math.min(scaleX, scaleY), 1.0f);
251         if (scale < 1.0f) {
252             int deltaX = (int) (r.width() * (scaleX - scale) * 0.5f);
253             r.left += deltaX;
254             r.right -= deltaX;
255 
256             int deltaY = (int) (r.height() * (scaleY - scale) * 0.5f);
257             r.top += deltaY;
258             r.bottom -= deltaY;
259         }
260         return scale;
261     }
262 
isSystemApp(Context context, Intent intent)263     static boolean isSystemApp(Context context, Intent intent) {
264         PackageManager pm = context.getPackageManager();
265         ComponentName cn = intent.getComponent();
266         String packageName = null;
267         if (cn == null) {
268             ResolveInfo info = pm.resolveActivity(intent, PackageManager.MATCH_DEFAULT_ONLY);
269             if ((info != null) && (info.activityInfo != null)) {
270                 packageName = info.activityInfo.packageName;
271             }
272         } else {
273             packageName = cn.getPackageName();
274         }
275         if (packageName != null) {
276             try {
277                 PackageInfo info = pm.getPackageInfo(packageName, 0);
278                 return (info != null) && (info.applicationInfo != null) &&
279                         ((info.applicationInfo.flags & ApplicationInfo.FLAG_SYSTEM) != 0);
280             } catch (NameNotFoundException e) {
281                 return false;
282             }
283         } else {
284             return false;
285         }
286     }
287 
288     /**
289      * This picks a dominant color, looking for high-saturation, high-value, repeated hues.
290      * @param bitmap The bitmap to scan
291      * @param samples The approximate max number of samples to use.
292      */
findDominantColorByHue(Bitmap bitmap, int samples)293     public static int findDominantColorByHue(Bitmap bitmap, int samples) {
294         final int height = bitmap.getHeight();
295         final int width = bitmap.getWidth();
296         int sampleStride = (int) Math.sqrt((height * width) / samples);
297         if (sampleStride < 1) {
298             sampleStride = 1;
299         }
300 
301         // This is an out-param, for getting the hsv values for an rgb
302         float[] hsv = new float[3];
303 
304         // First get the best hue, by creating a histogram over 360 hue buckets,
305         // where each pixel contributes a score weighted by saturation, value, and alpha.
306         float[] hueScoreHistogram = new float[360];
307         float highScore = -1;
308         int bestHue = -1;
309 
310         for (int y = 0; y < height; y += sampleStride) {
311             for (int x = 0; x < width; x += sampleStride) {
312                 int argb = bitmap.getPixel(x, y);
313                 int alpha = 0xFF & (argb >> 24);
314                 if (alpha < 0x80) {
315                     // Drop mostly-transparent pixels.
316                     continue;
317                 }
318                 // Remove the alpha channel.
319                 int rgb = argb | 0xFF000000;
320                 Color.colorToHSV(rgb, hsv);
321                 // Bucket colors by the 360 integer hues.
322                 int hue = (int) hsv[0];
323                 if (hue < 0 || hue >= hueScoreHistogram.length) {
324                     // Defensively avoid array bounds violations.
325                     continue;
326                 }
327                 float score = hsv[1] * hsv[2];
328                 hueScoreHistogram[hue] += score;
329                 if (hueScoreHistogram[hue] > highScore) {
330                     highScore = hueScoreHistogram[hue];
331                     bestHue = hue;
332                 }
333             }
334         }
335 
336         SparseArray<Float> rgbScores = new SparseArray<Float>();
337         int bestColor = 0xff000000;
338         highScore = -1;
339         // Go back over the RGB colors that match the winning hue,
340         // creating a histogram of weighted s*v scores, for up to 100*100 [s,v] buckets.
341         // The highest-scoring RGB color wins.
342         for (int y = 0; y < height; y += sampleStride) {
343             for (int x = 0; x < width; x += sampleStride) {
344                 int rgb = bitmap.getPixel(x, y) | 0xff000000;
345                 Color.colorToHSV(rgb, hsv);
346                 int hue = (int) hsv[0];
347                 if (hue == bestHue) {
348                     float s = hsv[1];
349                     float v = hsv[2];
350                     int bucket = (int) (s * 100) + (int) (v * 10000);
351                     // Score by cumulative saturation * value.
352                     float score = s * v;
353                     Float oldTotal = rgbScores.get(bucket);
354                     float newTotal = oldTotal == null ? score : oldTotal + score;
355                     rgbScores.put(bucket, newTotal);
356                     if (newTotal > highScore) {
357                         highScore = newTotal;
358                         // All the colors in the winning bucket are very similar. Last in wins.
359                         bestColor = rgb;
360                     }
361                 }
362             }
363         }
364         return bestColor;
365     }
366 
367     /*
368      * Finds a system apk which had a broadcast receiver listening to a particular action.
369      * @param action intent action used to find the apk
370      * @return a pair of apk package name and the resources.
371      */
findSystemApk(String action, PackageManager pm)372     static Pair<String, Resources> findSystemApk(String action, PackageManager pm) {
373         final Intent intent = new Intent(action);
374         for (ResolveInfo info : pm.queryBroadcastReceivers(intent, 0)) {
375             if (info.activityInfo != null &&
376                     (info.activityInfo.applicationInfo.flags & ApplicationInfo.FLAG_SYSTEM) != 0) {
377                 final String packageName = info.activityInfo.packageName;
378                 try {
379                     final Resources res = pm.getResourcesForApplication(packageName);
380                     return Pair.create(packageName, res);
381                 } catch (NameNotFoundException e) {
382                     Log.w(TAG, "Failed to find resources for " + packageName);
383                 }
384             }
385         }
386         return null;
387     }
388 
389     /**
390      * Compresses the bitmap to a byte array for serialization.
391      */
flattenBitmap(Bitmap bitmap)392     public static byte[] flattenBitmap(Bitmap bitmap) {
393         // Try go guesstimate how much space the icon will take when serialized
394         // to avoid unnecessary allocations/copies during the write.
395         int size = bitmap.getWidth() * bitmap.getHeight() * 4;
396         ByteArrayOutputStream out = new ByteArrayOutputStream(size);
397         try {
398             bitmap.compress(Bitmap.CompressFormat.PNG, 100, out);
399             out.flush();
400             out.close();
401             return out.toByteArray();
402         } catch (IOException e) {
403             Log.w(TAG, "Could not write bitmap");
404             return null;
405         }
406     }
407 
408     /**
409      * Trims the string, removing all whitespace at the beginning and end of the string.
410      * Non-breaking whitespaces are also removed.
411      */
trim(CharSequence s)412     public static String trim(CharSequence s) {
413         if (s == null) {
414             return null;
415         }
416 
417         // Just strip any sequence of whitespace or java space characters from the beginning and end
418         Matcher m = sTrimPattern.matcher(s);
419         return m.replaceAll("$1");
420     }
421 
422     /**
423      * Calculates the height of a given string at a specific text size.
424      */
calculateTextHeight(float textSizePx)425     public static int calculateTextHeight(float textSizePx) {
426         Paint p = new Paint();
427         p.setTextSize(textSizePx);
428         Paint.FontMetrics fm = p.getFontMetrics();
429         return (int) Math.ceil(fm.bottom - fm.top);
430     }
431 
432     /**
433      * Convenience println with multiple args.
434      */
println(String key, Object... args)435     public static void println(String key, Object... args) {
436         StringBuilder b = new StringBuilder();
437         b.append(key);
438         b.append(": ");
439         boolean isFirstArgument = true;
440         for (Object arg : args) {
441             if (isFirstArgument) {
442                 isFirstArgument = false;
443             } else {
444                 b.append(", ");
445             }
446             b.append(arg);
447         }
448         System.out.println(b.toString());
449     }
450 
isRtl(Resources res)451     public static boolean isRtl(Resources res) {
452         return res.getConfiguration().getLayoutDirection() == View.LAYOUT_DIRECTION_RTL;
453     }
454 
455     /**
456      * Returns true if the intent is a valid launch intent for a launcher activity of an app.
457      * This is used to identify shortcuts which are different from the ones exposed by the
458      * applications' manifest file.
459      *
460      * @param launchIntent The intent that will be launched when the shortcut is clicked.
461      */
isLauncherAppTarget(Intent launchIntent)462     public static boolean isLauncherAppTarget(Intent launchIntent) {
463         if (launchIntent != null
464                 && Intent.ACTION_MAIN.equals(launchIntent.getAction())
465                 && launchIntent.getComponent() != null
466                 && launchIntent.getCategories() != null
467                 && launchIntent.getCategories().size() == 1
468                 && launchIntent.hasCategory(Intent.CATEGORY_LAUNCHER)
469                 && TextUtils.isEmpty(launchIntent.getDataString())) {
470             // An app target can either have no extra or have ItemInfo.EXTRA_PROFILE.
471             Bundle extras = launchIntent.getExtras();
472             return extras == null || extras.keySet().isEmpty();
473         }
474         return false;
475     }
476 
dpiFromPx(int size, DisplayMetrics metrics)477     public static float dpiFromPx(int size, DisplayMetrics metrics){
478         float densityRatio = (float) metrics.densityDpi / DisplayMetrics.DENSITY_DEFAULT;
479         return (size / densityRatio);
480     }
pxFromDp(float size, DisplayMetrics metrics)481     public static int pxFromDp(float size, DisplayMetrics metrics) {
482         return (int) Math.round(TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP,
483                 size, metrics));
484     }
pxFromSp(float size, DisplayMetrics metrics)485     public static int pxFromSp(float size, DisplayMetrics metrics) {
486         return (int) Math.round(TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP,
487                 size, metrics));
488     }
489 
createDbSelectionQuery(String columnName, Iterable<?> values)490     public static String createDbSelectionQuery(String columnName, Iterable<?> values) {
491         return String.format(Locale.ENGLISH, "%s IN (%s)", columnName, TextUtils.join(", ", values));
492     }
493 
isBootCompleted()494     public static boolean isBootCompleted() {
495         return "1".equals(getSystemProperty("sys.boot_completed", "1"));
496     }
497 
getSystemProperty(String property, String defaultValue)498     public static String getSystemProperty(String property, String defaultValue) {
499         try {
500             Class clazz = Class.forName("android.os.SystemProperties");
501             Method getter = clazz.getDeclaredMethod("get", String.class);
502             String value = (String) getter.invoke(null, property);
503             if (!TextUtils.isEmpty(value)) {
504                 return value;
505             }
506         } catch (Exception e) {
507             Log.d(TAG, "Unable to read system properties");
508         }
509         return defaultValue;
510     }
511 
512     /**
513      * Ensures that a value is within given bounds. Specifically:
514      * If value is less than lowerBound, return lowerBound; else if value is greater than upperBound,
515      * return upperBound; else return value unchanged.
516      */
boundToRange(int value, int lowerBound, int upperBound)517     public static int boundToRange(int value, int lowerBound, int upperBound) {
518         return Math.max(lowerBound, Math.min(value, upperBound));
519     }
520 
521     /**
522      * @see #boundToRange(int, int, int).
523      */
boundToRange(float value, float lowerBound, float upperBound)524     public static float boundToRange(float value, float lowerBound, float upperBound) {
525         return Math.max(lowerBound, Math.min(value, upperBound));
526     }
527 
528     /**
529      * Wraps a message with a TTS span, so that a different message is spoken than
530      * what is getting displayed.
531      * @param msg original message
532      * @param ttsMsg message to be spoken
533      */
wrapForTts(CharSequence msg, String ttsMsg)534     public static CharSequence wrapForTts(CharSequence msg, String ttsMsg) {
535         SpannableString spanned = new SpannableString(msg);
536         spanned.setSpan(new TtsSpan.TextBuilder(ttsMsg).build(),
537                 0, spanned.length(), Spannable.SPAN_INCLUSIVE_INCLUSIVE);
538         return spanned;
539     }
540 
541     /**
542      * Replacement for Long.compare() which was added in API level 19.
543      */
longCompare(long lhs, long rhs)544     public static int longCompare(long lhs, long rhs) {
545         return lhs < rhs ? -1 : (lhs == rhs ? 0 : 1);
546     }
547 
getPrefs(Context context)548     public static SharedPreferences getPrefs(Context context) {
549         return context.getSharedPreferences(
550                 LauncherFiles.SHARED_PREFERENCES_KEY, Context.MODE_PRIVATE);
551     }
552 
isPowerSaverOn(Context context)553     public static boolean isPowerSaverOn(Context context) {
554         PowerManager powerManager = (PowerManager) context.getSystemService(Context.POWER_SERVICE);
555         return powerManager.isPowerSaveMode();
556     }
557 
isWallpaperAllowed(Context context)558     public static boolean isWallpaperAllowed(Context context) {
559         if (ATLEAST_NOUGAT) {
560             try {
561                 WallpaperManager wm = context.getSystemService(WallpaperManager.class);
562                 return (Boolean) wm.getClass().getDeclaredMethod("isSetWallpaperAllowed")
563                         .invoke(wm);
564             } catch (Exception e) { }
565         }
566         return true;
567     }
568 
closeSilently(Closeable c)569     public static void closeSilently(Closeable c) {
570         if (c != null) {
571             try {
572                 c.close();
573             } catch (IOException e) {
574                 if (ProviderConfig.IS_DOGFOOD_BUILD) {
575                     Log.d(TAG, "Error closing", e);
576                 }
577             }
578         }
579     }
580 
581     /**
582      * Returns true if {@param original} contains all entries defined in {@param updates} and
583      * have the same value.
584      * The comparison uses {@link Object#equals(Object)} to compare the values.
585      */
containsAll(Bundle original, Bundle updates)586     public static boolean containsAll(Bundle original, Bundle updates) {
587         for (String key : updates.keySet()) {
588             Object value1 = updates.get(key);
589             Object value2 = original.get(key);
590             if (value1 == null) {
591                 if (value2 != null) {
592                     return false;
593                 }
594             } else if (!value1.equals(value2)) {
595                 return false;
596             }
597         }
598         return true;
599     }
600 
601     /** Returns whether the collection is null or empty. */
isEmpty(Collection c)602     public static boolean isEmpty(Collection c) {
603         return c == null || c.isEmpty();
604     }
605 
sendCustomAccessibilityEvent(View target, int type, String text)606     public static void sendCustomAccessibilityEvent(View target, int type, String text) {
607         AccessibilityManager accessibilityManager = (AccessibilityManager)
608                 target.getContext().getSystemService(Context.ACCESSIBILITY_SERVICE);
609         if (accessibilityManager.isEnabled()) {
610             AccessibilityEvent event = AccessibilityEvent.obtain(type);
611             target.onInitializeAccessibilityEvent(event);
612             event.getText().add(text);
613             accessibilityManager.sendAccessibilityEvent(event);
614         }
615     }
616 
isBinderSizeError(Exception e)617     public static boolean isBinderSizeError(Exception e) {
618         return e.getCause() instanceof TransactionTooLargeException
619                 || e.getCause() instanceof DeadObjectException;
620     }
621 
getOverrideObject(Class<T> clazz, Context context, int resId)622     public static <T> T getOverrideObject(Class<T> clazz, Context context, int resId) {
623         String className = context.getString(resId);
624         if (!TextUtils.isEmpty(className)) {
625             try {
626                 Class<?> cls = Class.forName(className);
627                 return (T) cls.getDeclaredConstructor(Context.class).newInstance(context);
628             } catch (ClassNotFoundException | InstantiationException | IllegalAccessException
629                     | ClassCastException | NoSuchMethodException | InvocationTargetException e) {
630                 Log.e(TAG, "Bad overriden class", e);
631             }
632         }
633 
634         try {
635             return clazz.newInstance();
636         } catch (InstantiationException|IllegalAccessException e) {
637             throw new RuntimeException(e);
638         }
639     }
640 
641     /**
642      * Returns a HashSet with a single element. We use this instead of Collections.singleton()
643      * because HashSet ensures all operations, such as remove, are supported.
644      */
singletonHashSet(T elem)645     public static <T> HashSet<T> singletonHashSet(T elem) {
646         HashSet<T> hashSet = new HashSet<>(1);
647         hashSet.add(elem);
648         return hashSet;
649     }
650 }
651