Tusky-App-Android/app/src/main/java/com/keylesspalace/tusky/util/SpanUtils.java

143 lines
4.8 KiB
Java

/* Copyright 2017 Andrew Dawson
*
* This file is a part of Tusky.
*
* This program is free software; you can redistribute it and/or modify it under the terms of the
* GNU General Public License as published by the Free Software Foundation; either version 3 of the
* License, or (at your option) any later version.
*
* Tusky is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even
* the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
* Public License for more details.
*
* You should have received a copy of the GNU General Public License along with Tusky; if not,
* see <http://www.gnu.org/licenses>. */
package com.keylesspalace.tusky.util;
import android.text.Spannable;
import android.text.Spanned;
import android.text.style.ForegroundColorSpan;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class SpanUtils {
/**
* @see <a href="https://github.com/tootsuite/mastodon/blob/master/app/models/tag.rb">
* Tag#HASHTAG_RE</a>.
*/
private static final String TAG_REGEX = "(?:^|[^/)\\w])#([\\w_]*[\\p{Alpha}_][\\w_]*)";
private static Pattern TAG_PATTERN = Pattern.compile(TAG_REGEX, Pattern.CASE_INSENSITIVE);
/**
* @see <a href="https://github.com/tootsuite/mastodon/blob/master/app/models/account.rb">
* Account#MENTION_RE</a>
*/
private static final String MENTION_REGEX =
"(?:^|[^/[:word:]])@([a-z0-9_]+(?:@[a-z0-9\\.\\-]+[a-z0-9]+)?)";
private static Pattern MENTION_PATTERN =
Pattern.compile(MENTION_REGEX, Pattern.CASE_INSENSITIVE);
private static class FindCharsResult {
int charIndex;
int stringIndex;
FindCharsResult() {
charIndex = -1;
stringIndex = -1;
}
}
private static FindCharsResult findChars(String string, int fromIndex, char[] chars) {
FindCharsResult result = new FindCharsResult();
final int length = string.length();
for (int i = fromIndex; i < length; i++) {
char c = string.charAt(i);
for (int j = 0; j < chars.length; j++) {
if (chars[j] == c) {
result.charIndex = j;
result.stringIndex = i;
return result;
}
}
}
return result;
}
private static FindCharsResult findStart(String string, int fromIndex, char[] chars) {
final int length = string.length();
while (fromIndex < length) {
FindCharsResult found = findChars(string, fromIndex, chars);
int i = found.stringIndex;
if (i < 0) {
break;
} else if (i == 0 || i >= 1 && Character.isWhitespace(string.codePointBefore(i))) {
return found;
} else {
fromIndex = i + 1;
}
}
return new FindCharsResult();
}
private static int findEndOfHashtag(String string, int fromIndex) {
Matcher matcher = TAG_PATTERN.matcher(string);
if (fromIndex >= 1) {
fromIndex--;
}
boolean found = matcher.find(fromIndex);
if (found) {
return matcher.end();
} else {
return -1;
}
}
private static int findEndOfMention(String string, int fromIndex) {
Matcher matcher = MENTION_PATTERN.matcher(string);
if (fromIndex >= 1) {
fromIndex--;
}
boolean found = matcher.find(fromIndex);
if (found) {
return matcher.end();
} else {
return -1;
}
}
/** Takes text containing mentions and hashtags and makes them the given colour. */
public static void highlightSpans(Spannable text, int colour) {
// Strip all existing colour spans.
int n = text.length();
ForegroundColorSpan[] oldSpans = text.getSpans(0, n, ForegroundColorSpan.class);
for (int i = oldSpans.length - 1; i >= 0; i--) {
text.removeSpan(oldSpans[i]);
}
// Colour the mentions and hashtags.
String string = text.toString();
int start;
int end = 0;
while (end < n) {
char[] chars = { '#', '@' };
FindCharsResult found = findStart(string, end, chars);
start = found.stringIndex;
if (start < 0) {
break;
}
if (found.charIndex == 0) {
end = findEndOfHashtag(string, start);
} else if (found.charIndex == 1) {
end = findEndOfMention(string, start);
} else {
break;
}
if (end < 0) {
break;
}
text.setSpan(new ForegroundColorSpan(colour), start, end,
Spanned.SPAN_INCLUSIVE_EXCLUSIVE);
}
}
}