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+/*
+ * Copyright (C) 2009 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package com.android.inputmethod.latin;
+
+import com.android.inputmethod.compat.InputConnectionCompatUtils;
+
+import android.text.TextUtils;
+import android.view.inputmethod.ExtractedText;
+import android.view.inputmethod.ExtractedTextRequest;
+import android.view.inputmethod.InputConnection;
+
+import java.util.regex.Pattern;
+
+/**
+ * Utility methods to deal with editing text through an InputConnection.
+ */
+public class EditingUtils {
+ /**
+ * Number of characters we want to look back in order to identify the previous word
+ */
+ private static final int LOOKBACK_CHARACTER_NUM = 15;
+
+ private EditingUtils() {
+ // Unintentional empty constructor for singleton.
+ }
+
+ /**
+ * Append newText to the text field represented by connection.
+ * The new text becomes selected.
+ */
+ public static void appendText(InputConnection connection, String newText) {
+ if (connection == null) {
+ return;
+ }
+
+ // Commit the composing text
+ connection.finishComposingText();
+
+ // Add a space if the field already has text.
+ String text = newText;
+ CharSequence charBeforeCursor = connection.getTextBeforeCursor(1, 0);
+ if (charBeforeCursor != null
+ && !charBeforeCursor.equals(" ")
+ && (charBeforeCursor.length() > 0)) {
+ text = " " + text;
+ }
+
+ connection.setComposingText(text, 1);
+ }
+
+ private static int getCursorPosition(InputConnection connection) {
+ ExtractedText extracted = connection.getExtractedText(
+ new ExtractedTextRequest(), 0);
+ if (extracted == null) {
+ return -1;
+ }
+ return extracted.startOffset + extracted.selectionStart;
+ }
+
+ /**
+ * @param connection connection to the current text field.
+ * @param separators characters which may separate words
+ * @return the word that surrounds the cursor, including up to one trailing
+ * separator. For example, if the field contains "he|llo world", where |
+ * represents the cursor, then "hello " will be returned.
+ */
+ public static String getWordAtCursor(InputConnection connection, String separators) {
+ Range r = getWordRangeAtCursor(connection, separators);
+ return (r == null) ? null : r.mWord;
+ }
+
+ /**
+ * Removes the word surrounding the cursor. Parameters are identical to
+ * getWordAtCursor.
+ */
+ public static void deleteWordAtCursor(InputConnection connection, String separators) {
+ Range range = getWordRangeAtCursor(connection, separators);
+ if (range == null) return;
+
+ connection.finishComposingText();
+ // Move cursor to beginning of word, to avoid crash when cursor is outside
+ // of valid range after deleting text.
+ int newCursor = getCursorPosition(connection) - range.mCharsBefore;
+ connection.setSelection(newCursor, newCursor);
+ connection.deleteSurroundingText(0, range.mCharsBefore + range.mCharsAfter);
+ }
+
+ /**
+ * Represents a range of text, relative to the current cursor position.
+ */
+ public static class Range {
+ /** Characters before selection start */
+ public final int mCharsBefore;
+
+ /**
+ * Characters after selection start, including one trailing word
+ * separator.
+ */
+ public final int mCharsAfter;
+
+ /** The actual characters that make up a word */
+ public final String mWord;
+
+ public Range(int charsBefore, int charsAfter, String word) {
+ if (charsBefore < 0 || charsAfter < 0) {
+ throw new IndexOutOfBoundsException();
+ }
+ this.mCharsBefore = charsBefore;
+ this.mCharsAfter = charsAfter;
+ this.mWord = word;
+ }
+ }
+
+ private static Range getWordRangeAtCursor(InputConnection connection, String sep) {
+ if (connection == null || sep == null) {
+ return null;
+ }
+ CharSequence before = connection.getTextBeforeCursor(1000, 0);
+ CharSequence after = connection.getTextAfterCursor(1000, 0);
+ if (before == null || after == null) {
+ return null;
+ }
+
+ // Find first word separator before the cursor
+ int start = before.length();
+ while (start > 0 && !isWhitespace(before.charAt(start - 1), sep)) start--;
+
+ // Find last word separator after the cursor
+ int end = -1;
+ while (++end < after.length() && !isWhitespace(after.charAt(end), sep)) {
+ // Nothing to do here.
+ }
+
+ int cursor = getCursorPosition(connection);
+ if (start >= 0 && cursor + end <= after.length() + before.length()) {
+ String word = before.toString().substring(start, before.length())
+ + after.toString().substring(0, end);
+ return new Range(before.length() - start, end, word);
+ }
+
+ return null;
+ }
+
+ private static boolean isWhitespace(int code, String whitespace) {
+ return whitespace.contains(String.valueOf((char) code));
+ }
+
+ private static final Pattern spaceRegex = Pattern.compile("\\s+");
+
+
+ public static CharSequence getPreviousWord(InputConnection connection,
+ String sentenceSeperators) {
+ //TODO: Should fix this. This could be slow!
+ CharSequence prev = connection.getTextBeforeCursor(LOOKBACK_CHARACTER_NUM, 0);
+ return getPreviousWord(prev, sentenceSeperators);
+ }
+
+ // Get the word before the whitespace preceding the non-whitespace preceding the cursor.
+ // Also, it won't return words that end in a separator.
+ // Example :
+ // "abc def|" -> abc
+ // "abc def |" -> abc
+ // "abc def. |" -> abc
+ // "abc def . |" -> def
+ // "abc|" -> null
+ // "abc |" -> null
+ // "abc. def|" -> null
+ public static CharSequence getPreviousWord(CharSequence prev, String sentenceSeperators) {
+ if (prev == null) return null;
+ String[] w = spaceRegex.split(prev);
+
+ // If we can't find two words, or we found an empty word, return null.
+ if (w.length < 2 || w[w.length - 2].length() <= 0) return null;
+
+ // If ends in a separator, return null
+ char lastChar = w[w.length - 2].charAt(w[w.length - 2].length() - 1);
+ if (sentenceSeperators.contains(String.valueOf(lastChar))) return null;
+
+ return w[w.length - 2];
+ }
+
+ public static CharSequence getThisWord(InputConnection connection, String sentenceSeperators) {
+ final CharSequence prev = connection.getTextBeforeCursor(LOOKBACK_CHARACTER_NUM, 0);
+ return getThisWord(prev, sentenceSeperators);
+ }
+
+ // Get the word immediately before the cursor, even if there is whitespace between it and
+ // the cursor - but not if there is punctuation.
+ // Example :
+ // "abc def|" -> def
+ // "abc def |" -> def
+ // "abc def. |" -> null
+ // "abc def . |" -> null
+ public static CharSequence getThisWord(CharSequence prev, String sentenceSeperators) {
+ if (prev == null) return null;
+ String[] w = spaceRegex.split(prev);
+
+ // No word : return null
+ if (w.length < 1 || w[w.length - 1].length() <= 0) return null;
+
+ // If ends in a separator, return null
+ char lastChar = w[w.length - 1].charAt(w[w.length - 1].length() - 1);
+ if (sentenceSeperators.contains(String.valueOf(lastChar))) return null;
+
+ return w[w.length - 1];
+ }
+
+ public static class SelectedWord {
+ public final int mStart;
+ public final int mEnd;
+ public final CharSequence mWord;
+
+ public SelectedWord(int start, int end, CharSequence word) {
+ mStart = start;
+ mEnd = end;
+ mWord = word;
+ }
+ }
+
+ /**
+ * Takes a character sequence with a single character and checks if the character occurs
+ * in a list of word separators or is empty.
+ * @param singleChar A CharSequence with null, zero or one character
+ * @param wordSeparators A String containing the word separators
+ * @return true if the character is at a word boundary, false otherwise
+ */
+ private static boolean isWordBoundary(CharSequence singleChar, String wordSeparators) {
+ return TextUtils.isEmpty(singleChar) || wordSeparators.contains(singleChar);
+ }
+
+ /**
+ * Checks if the cursor is inside a word or the current selection is a whole word.
+ * @param ic the InputConnection for accessing the text field
+ * @param selStart the start position of the selection within the text field
+ * @param selEnd the end position of the selection within the text field. This could be
+ * the same as selStart, if there's no selection.
+ * @param wordSeparators the word separator characters for the current language
+ * @return an object containing the text and coordinates of the selected/touching word,
+ * null if the selection/cursor is not marking a whole word.
+ */
+ public static SelectedWord getWordAtCursorOrSelection(final InputConnection ic,
+ int selStart, int selEnd, String wordSeparators) {
+ if (selStart == selEnd) {
+ // There is just a cursor, so get the word at the cursor
+ EditingUtils.Range range = getWordRangeAtCursor(ic, wordSeparators);
+ if (range != null && !TextUtils.isEmpty(range.mWord)) {
+ return new SelectedWord(selStart - range.mCharsBefore, selEnd + range.mCharsAfter,
+ range.mWord);
+ }
+ } else {
+ // Is the previous character empty or a word separator? If not, return null.
+ CharSequence charsBefore = ic.getTextBeforeCursor(1, 0);
+ if (!isWordBoundary(charsBefore, wordSeparators)) {
+ return null;
+ }
+
+ // Is the next character empty or a word separator? If not, return null.
+ CharSequence charsAfter = ic.getTextAfterCursor(1, 0);
+ if (!isWordBoundary(charsAfter, wordSeparators)) {
+ return null;
+ }
+
+ // Extract the selection alone
+ CharSequence touching = InputConnectionCompatUtils.getSelectedText(
+ ic, selStart, selEnd);
+ if (TextUtils.isEmpty(touching)) return null;
+ // Is any part of the selection a separator? If so, return null.
+ final int length = touching.length();
+ for (int i = 0; i < length; i++) {
+ if (wordSeparators.contains(touching.subSequence(i, i + 1))) {
+ return null;
+ }
+ }
+ // Prepare the selected word
+ return new SelectedWord(selStart, selEnd, touching);
+ }
+ return null;
+ }
+}