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      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 import android.text.style.URLSpan;
     26 
     27 public final class SpannableStringUtils {
     28     /**
     29      * Copies the spans from the region <code>start...end</code> in
     30      * <code>source</code> to the region
     31      * <code>destoff...destoff+end-start</code> in <code>dest</code>.
     32      * Spans in <code>source</code> that begin before <code>start</code>
     33      * or end after <code>end</code> but overlap this range are trimmed
     34      * as if they began at <code>start</code> or ended at <code>end</code>.
     35      * Only SuggestionSpans that don't have the SPAN_PARAGRAPH span are copied.
     36      *
     37      * This code is almost entirely taken from {@link TextUtils#copySpansFrom}, except for the
     38      * kind of span that is copied.
     39      *
     40      * @throws IndexOutOfBoundsException if any of the copied spans
     41      * are out of range in <code>dest</code>.
     42      */
     43     public static void copyNonParagraphSuggestionSpansFrom(Spanned source, int start, int end,
     44             Spannable dest, int destoff) {
     45         Object[] spans = source.getSpans(start, end, SuggestionSpan.class);
     46 
     47         for (int i = 0; i < spans.length; i++) {
     48             int fl = source.getSpanFlags(spans[i]);
     49             // We don't care about the PARAGRAPH flag in LatinIME code. However, if this flag
     50             // is set, Spannable#setSpan will throw an exception unless the span is on the edge
     51             // of a word. But the spans have been split into two by the getText{Before,After}Cursor
     52             // methods, so after concatenation they may end in the middle of a word.
     53             // Since we don't use them, we can just remove them and avoid crashing.
     54             fl &= ~Spannable.SPAN_PARAGRAPH;
     55 
     56             int st = source.getSpanStart(spans[i]);
     57             int en = source.getSpanEnd(spans[i]);
     58 
     59             if (st < start)
     60                 st = start;
     61             if (en > end)
     62                 en = end;
     63 
     64             dest.setSpan(spans[i], st - start + destoff, en - start + destoff,
     65                          fl);
     66         }
     67     }
     68 
     69     /**
     70      * Returns a CharSequence concatenating the specified CharSequences, retaining their
     71      * SuggestionSpans that don't have the PARAGRAPH flag, but not other spans.
     72      *
     73      * This code is almost entirely taken from {@link TextUtils#concat(CharSequence...)}, except
     74      * it calls copyNonParagraphSuggestionSpansFrom instead of {@link TextUtils#copySpansFrom}.
     75      */
     76     public static CharSequence concatWithNonParagraphSuggestionSpansOnly(CharSequence... text) {
     77         if (text.length == 0) {
     78             return "";
     79         }
     80 
     81         if (text.length == 1) {
     82             return text[0];
     83         }
     84 
     85         boolean spanned = false;
     86         for (int i = 0; i < text.length; i++) {
     87             if (text[i] instanceof Spanned) {
     88                 spanned = true;
     89                 break;
     90             }
     91         }
     92 
     93         StringBuilder sb = new StringBuilder();
     94         for (int i = 0; i < text.length; i++) {
     95             sb.append(text[i]);
     96         }
     97 
     98         if (!spanned) {
     99             return sb.toString();
    100         }
    101 
    102         SpannableString ss = new SpannableString(sb);
    103         int off = 0;
    104         for (int i = 0; i < text.length; i++) {
    105             int len = text[i].length();
    106 
    107             if (text[i] instanceof Spanned) {
    108                 copyNonParagraphSuggestionSpansFrom((Spanned) text[i], 0, len, ss, off);
    109             }
    110 
    111             off += len;
    112         }
    113 
    114         return new SpannedString(ss);
    115     }
    116 
    117     public static boolean hasUrlSpans(final CharSequence text,
    118             final int startIndex, final int endIndex) {
    119         if (!(text instanceof Spanned)) {
    120             return false; // Not spanned, so no link
    121         }
    122         final Spanned spanned = (Spanned)text;
    123         // getSpans(x, y) does not return spans that start on x or end on y. x-1, y+1 does the
    124         // trick, and works in all cases even if startIndex <= 0 or endIndex >= text.length().
    125         final URLSpan[] spans = spanned.getSpans(startIndex - 1, endIndex + 1, URLSpan.class);
    126         return null != spans && spans.length > 0;
    127     }
    128 }
    129