Home | History | Annotate | Download | only in utils 
      1 /*
      2  * Copyright (C) 2013 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.inputmethod.latin.utils;
     18 
     19 import android.text.Spannable;
     20 import android.text.SpannableString;
     21 import android.text.Spanned;
     22 import android.text.SpannedString;
     23 import android.text.TextUtils;
     24 import android.text.style.SuggestionSpan;
     25 
     26 public final class SpannableStringUtils {
     27     /**
     28      * Copies the spans from the region <code>start...end</code> in
     29      * <code>source</code> to the region
     30      * <code>destoff...destoff+end-start</code> in <code>dest</code>.
     31      * Spans in <code>source</code> that begin before <code>start</code>
     32      * or end after <code>end</code> but overlap this range are trimmed
     33      * as if they began at <code>start</code> or ended at <code>end</code>.
     34      * Only SuggestionSpans that don't have the SPAN_PARAGRAPH span are copied.
     35      *
     36      * This code is almost entirely taken from {@link TextUtils#copySpansFrom}, except for the
     37      * kind of span that is copied.
     38      *
     39      * @throws IndexOutOfBoundsException if any of the copied spans
     40      * are out of range in <code>dest</code>.
     41      */
     42     public static void copyNonParagraphSuggestionSpansFrom(Spanned source, int start, int end,
     43                                      Spannable dest, int destoff) {
     44         Object[] spans = source.getSpans(start, end, SuggestionSpan.class);
     45 
     46         for (int i = 0; i < spans.length; i++) {
     47             int fl = source.getSpanFlags(spans[i]);
     48             if (0 != (fl & Spannable.SPAN_PARAGRAPH)) continue;
     49 
     50             int st = source.getSpanStart(spans[i]);
     51             int en = source.getSpanEnd(spans[i]);
     52 
     53             if (st < start)
     54                 st = start;
     55             if (en > end)
     56                 en = end;
     57 
     58             dest.setSpan(spans[i], st - start + destoff, en - start + destoff,
     59                          fl);
     60         }
     61     }
     62 
     63     /**
     64      * Returns a CharSequence concatenating the specified CharSequences, retaining their
     65      * SuggestionSpans that don't have the PARAGRAPH flag, but not other spans.
     66      *
     67      * This code is almost entirely taken from {@link TextUtils#concat(CharSequence...)}, except
     68      * it calls copyNonParagraphSuggestionSpansFrom instead of {@link TextUtils#copySpansFrom}.
     69      */
     70     public static CharSequence concatWithNonParagraphSuggestionSpansOnly(CharSequence... text) {
     71         if (text.length == 0) {
     72             return "";
     73         }
     74 
     75         if (text.length == 1) {
     76             return text[0];
     77         }
     78 
     79         boolean spanned = false;
     80         for (int i = 0; i < text.length; i++) {
     81             if (text[i] instanceof Spanned) {
     82                 spanned = true;
     83                 break;
     84             }
     85         }
     86 
     87         StringBuilder sb = new StringBuilder();
     88         for (int i = 0; i < text.length; i++) {
     89             sb.append(text[i]);
     90         }
     91 
     92         if (!spanned) {
     93             return sb.toString();
     94         }
     95 
     96         SpannableString ss = new SpannableString(sb);
     97         int off = 0;
     98         for (int i = 0; i < text.length; i++) {
     99             int len = text[i].length();
    100 
    101             if (text[i] instanceof Spanned) {
    102                 copyNonParagraphSuggestionSpansFrom((Spanned) text[i], 0, len, ss, off);
    103             }
    104 
    105             off += len;
    106         }
    107 
    108         return new SpannedString(ss);
    109     }
    110 }
    111