/*
* 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.sugree.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 static final int INVALID_CURSOR_POSITION = -1;
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) {
if (null == connection) return INVALID_CURSOR_POSITION;
ExtractedText extracted = connection.getExtractedText(
new ExtractedTextRequest(), 0);
if (extracted == null) {
return INVALID_CURSOR_POSITION;
}
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) {
// getWordRangeAtCursor returns null if the connection is null
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) {
// getWordRangeAtCursor returns null if the connection is null
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!
if (null == connection) return null;
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) {
if (null == connection) return null;
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
// getWordRangeAtCursor returns null if the connection is null
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 {
if (null == ic) return null;
// 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;
}
}