/*
* 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.s16.inputmethod.skeyboard;
import android.text.TextUtils;
import android.view.inputmethod.ExtractedText;
import android.view.inputmethod.ExtractedTextRequest;
import android.view.inputmethod.InputConnection;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.regex.Pattern;
/**
* 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;
// Cache Method pointers
private static boolean sMethodsInitialized;
private static Method sMethodGetSelectedText;
private static Method sMethodSetComposingRegion;
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;
}
/**
* @param connection connection to the current text field.
* @param sep characters which may separate words
* @param range the range object to store the result into
* @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;
}
}
public static class SelectedWord {
public int start;
public int end;
public CharSequence 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
EditingUtil.Range range = new EditingUtil.Range();
CharSequence touching = getWordAtCursor(ic, wordSeparators, range);
if (!TextUtils.isEmpty(touching)) {
SelectedWord selWord = new SelectedWord();
selWord.word = touching;
selWord.start = selStart - range.charsBefore;
selWord.end = selEnd + range.charsAfter;
return selWord;
}
} 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 = 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
SelectedWord selWord = new SelectedWord();
selWord.start = selStart;
selWord.end = selEnd;
selWord.word = touching;
return selWord;
}
return null;
}
/**
* Cache method pointers for performance
*/
private static void initializeMethodsForReflection() {
try {
// These will either both exist or not, so no need for separate try/catch blocks.
// If other methods are added later, use separate try/catch blocks.
sMethodGetSelectedText = InputConnection.class.getMethod("getSelectedText", int.class);
sMethodSetComposingRegion = InputConnection.class.getMethod("setComposingRegion",
int.class, int.class);
} catch (NoSuchMethodException exc) {
// Ignore
}
sMethodsInitialized = true;
}
/**
* Returns the selected text between the selStart and selEnd positions.
*/
private static CharSequence getSelectedText(InputConnection ic, int selStart, int selEnd) {
// Use reflection, for backward compatibility
CharSequence result = null;
if (!sMethodsInitialized) {
initializeMethodsForReflection();
}
if (sMethodGetSelectedText != null) {
try {
result = (CharSequence) sMethodGetSelectedText.invoke(ic, 0);
return result;
} catch (InvocationTargetException exc) {
// Ignore
} catch (IllegalArgumentException e) {
// Ignore
} catch (IllegalAccessException e) {
// Ignore
}
}
// Reflection didn't work, try it the poor way, by moving the cursor to the start,
// getting the text after the cursor and moving the text back to selected mode.
// TODO: Verify that this works properly in conjunction with
// LatinIME#onUpdateSelection
ic.setSelection(selStart, selEnd);
result = ic.getTextAfterCursor(selEnd - selStart, 0);
ic.setSelection(selStart, selEnd);
return result;
}
/**
* Tries to set the text into composition mode if there is support for it in the framework.
*/
public static void underlineWord(InputConnection ic, SelectedWord word) {
// Use reflection, for backward compatibility
// If method not found, there's nothing we can do. It still works but just wont underline
// the word.
if (!sMethodsInitialized) {
initializeMethodsForReflection();
}
if (sMethodSetComposingRegion != null) {
try {
sMethodSetComposingRegion.invoke(ic, word.start, word.end);
} catch (InvocationTargetException exc) {
// Ignore
} catch (IllegalArgumentException e) {
// Ignore
} catch (IllegalAccessException e) {
// Ignore
}
}
}
}