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/*
* Copyright (C) 2009 Google Inc.
*
* 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 java.util.regex.Pattern;
import android.view.inputmethod.ExtractedText;
import android.view.inputmethod.ExtractedTextRequest;
import android.view.inputmethod.InputConnection;
/**
* Utility methods to deal with editing text through an InputConnection.
*/
public class EditingUtil {
/**
* Number of characters we want to look back in order to identify the previous word
*/
private static final int LOOKBACK_CHARACTER_NUM = 15;
private EditingUtil() {};
/**
* 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.
CharSequence charBeforeCursor = connection.getTextBeforeCursor(1, 0);
if (charBeforeCursor != null
&& !charBeforeCursor.equals(" ")
&& (charBeforeCursor.length() > 0)) {
newText = " " + newText;
}
connection.setComposingText(newText, 1);
}
private static int getCursorPosition(InputConnection connection) {
ExtractedText extracted = connection.getExtractedText(
new ExtractedTextRequest(), 0);
if (extracted == null) {
return -1;
}
return extracted.startOffset + extracted.selectionStart;
}
private static int getSelectionEnd(InputConnection connection) {
ExtractedText extracted = connection.getExtractedText(
new ExtractedTextRequest(), 0);
if (extracted == null) {
return -1;
}
return extracted.startOffset + extracted.selectionEnd;
}
/**
* @param connection connection to the current text field.
* @param sep 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) {
return getWordAtCursor(connection, separators, null);
}
/**
* @param connection connection to the current text field.
* @param sep 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 range) {
Range r = getWordRangeAtCursor(connection, separators, range);
return (r == null) ? null : r.word;
}
/**
* Removes the word surrounding the cursor. Parameters are identical to
* getWordAtCursor.
*/
public static void deleteWordAtCursor(
InputConnection connection, String separators) {
Range range = getWordRangeAtCursor(connection, separators, null);
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.charsBefore;
connection.setSelection(newCursor, newCursor);
connection.deleteSurroundingText(0, range.charsBefore + range.charsAfter);
}
/**
* Represents a range of text, relative to the current cursor position.
*/
public static class Range {
/** Characters before selection start */
public int charsBefore;
/**
* Characters after selection start, including one trailing word
* separator.
*/
public int charsAfter;
/** The actual characters that make up a word */
public String word;
public Range() {}
public Range(int charsBefore, int charsAfter, String word) {
if (charsBefore < 0 || charsAfter < 0) {
throw new IndexOutOfBoundsException();
}
this.charsBefore = charsBefore;
this.charsAfter = charsAfter;
this.word = word;
}
}
private static Range getWordRangeAtCursor(
InputConnection connection, String sep, Range range) {
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));
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);
Range returnRange = range != null? range : new Range();
returnRange.charsBefore = before.length() - start;
returnRange.charsAfter = end;
returnRange.word = word;
return returnRange;
}
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);
if (prev == null) {
return null;
}
String[] w = spaceRegex.split(prev);
if (w.length >= 2 && w[w.length-2].length() > 0) {
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];
} else {
return null;
}
}
}
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