Fix bug #7173351 API REVIEW: android.util.LocaleUtil

Change-Id: I08fd491eff714059e9ec874fadebe7eb556c34d5

1 files changed, 57 insertions, 0 deletions

diff --git a/core/java/android/text/TextUtils.java b/core/java/android/text/TextUtils.java
index 987062ab08a2..1508d10ea6af 100644
--- a/core/java/android/text/TextUtils.java
+++ b/core/java/android/text/TextUtils.java
@@ -46,11 +46,14 @@ import android.text.style.URLSpan;
 import android.text.style.UnderlineSpan;
 import android.util.Printer;
 
+import android.view.View;
 import com.android.internal.R;
 import com.android.internal.util.ArrayUtils;
+import libcore.icu.ICU;
 
 import java.lang.reflect.Array;
 import java.util.Iterator;
+import java.util.Locale;
 import java.util.regex.Pattern;
 
 public class TextUtils {
@@ -1706,10 +1709,64 @@ public class TextUtils {
         return (int) (range & 0x00000000FFFFFFFFL);
     }
 
+    /**
+     * Return the layout direction for a given Locale
+     *
+     * @param locale the Locale for which we want the layout direction. Can be null.
+     * @return the layout direction. This may be one of:
+     * {@link android.view.View#LAYOUT_DIRECTION_LTR} or
+     * {@link android.view.View#LAYOUT_DIRECTION_RTL}.
+     *
+     * Be careful: this code will need to be updated when vertical scripts will be supported
+     */
+    public static int getLayoutDirectionFromLocale(Locale locale) {
+        if (locale != null && !locale.equals(Locale.ROOT)) {
+            final String scriptSubtag = ICU.getScript(ICU.addLikelySubtags(locale.toString()));
+            if (scriptSubtag == null) return getLayoutDirectionFromFirstChar(locale);
+
+            if (scriptSubtag.equalsIgnoreCase(ARAB_SCRIPT_SUBTAG) ||
+                    scriptSubtag.equalsIgnoreCase(HEBR_SCRIPT_SUBTAG)) {
+                return View.LAYOUT_DIRECTION_RTL;
+            }
+        }
+
+        return View.LAYOUT_DIRECTION_LTR;
+    }
+
+    /**
+     * Fallback algorithm to detect the locale direction. Rely on the fist char of the
+     * localized locale name. This will not work if the localized locale name is in English
+     * (this is the case for ICU 4.4 and "Urdu" script)
+     *
+     * @param locale
+     * @return the layout direction. This may be one of:
+     * {@link View#LAYOUT_DIRECTION_LTR} or
+     * {@link View#LAYOUT_DIRECTION_RTL}.
+     *
+     * Be careful: this code will need to be updated when vertical scripts will be supported
+     *
+     * @hide
+     */
+    private static int getLayoutDirectionFromFirstChar(Locale locale) {
+        switch(Character.getDirectionality(locale.getDisplayName(locale).charAt(0))) {
+            case Character.DIRECTIONALITY_RIGHT_TO_LEFT:
+            case Character.DIRECTIONALITY_RIGHT_TO_LEFT_ARABIC:
+                return View.LAYOUT_DIRECTION_RTL;
+
+            case Character.DIRECTIONALITY_LEFT_TO_RIGHT:
+            default:
+                return View.LAYOUT_DIRECTION_LTR;
+        }
+    }
+
     private static Object sLock = new Object();
+
     private static char[] sTemp = null;
 
     private static String[] EMPTY_STRING_ARRAY = new String[]{};
 
     private static final char ZWNBS_CHAR = '\uFEFF';
+
+    private static String ARAB_SCRIPT_SUBTAG = "Arab";
+    private static String HEBR_SCRIPT_SUBTAG = "Hebr";
 }