430 lines
13 KiB
Java
430 lines
13 KiB
Java
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/*
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* Copyright (C) 2006 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package android.text;
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/**
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* Utility class for manipulating cursors and selections in CharSequences.
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* A cursor is a selection where the start and end are at the same offset.
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*/
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public class Selection {
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private Selection() { /* cannot be instantiated */ }
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/*
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* Retrieving the selection
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*/
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/**
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* Return the offset of the selection anchor or cursor, or -1 if
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* there is no selection or cursor.
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*/
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public static final int getSelectionStart(CharSequence text) {
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if (text instanceof Spanned)
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return ((Spanned) text).getSpanStart(SELECTION_START);
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else
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return -1;
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}
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/**
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* Return the offset of the selection edge or cursor, or -1 if
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* there is no selection or cursor.
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*/
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public static final int getSelectionEnd(CharSequence text) {
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if (text instanceof Spanned)
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return ((Spanned) text).getSpanStart(SELECTION_END);
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else
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return -1;
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}
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/*
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* Setting the selection
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*/
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// private static int pin(int value, int min, int max) {
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// return value < min ? 0 : (value > max ? max : value);
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// }
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/**
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* Set the selection anchor to <code>start</code> and the selection edge
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* to <code>stop</code>.
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*/
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public static void setSelection(Spannable text, int start, int stop) {
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// int len = text.length();
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// start = pin(start, 0, len); XXX remove unless we really need it
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// stop = pin(stop, 0, len);
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int ostart = getSelectionStart(text);
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int oend = getSelectionEnd(text);
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if (ostart != start || oend != stop) {
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text.setSpan(SELECTION_START, start, start,
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Spanned.SPAN_POINT_POINT|Spanned.SPAN_INTERMEDIATE);
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text.setSpan(SELECTION_END, stop, stop,
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Spanned.SPAN_POINT_POINT);
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}
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}
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/**
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* Move the cursor to offset <code>index</code>.
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*/
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public static final void setSelection(Spannable text, int index) {
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setSelection(text, index, index);
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}
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/**
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* Select the entire text.
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*/
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public static final void selectAll(Spannable text) {
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setSelection(text, 0, text.length());
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}
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/**
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* Move the selection edge to offset <code>index</code>.
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*/
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public static final void extendSelection(Spannable text, int index) {
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if (text.getSpanStart(SELECTION_END) != index)
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text.setSpan(SELECTION_END, index, index, Spanned.SPAN_POINT_POINT);
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}
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/**
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* Remove the selection or cursor, if any, from the text.
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*/
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public static final void removeSelection(Spannable text) {
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text.removeSpan(SELECTION_START);
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text.removeSpan(SELECTION_END);
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}
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/*
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* Moving the selection within the layout
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*/
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/**
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* Move the cursor to the buffer offset physically above the current
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* offset, or return false if the cursor is already on the top line.
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*/
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public static boolean moveUp(Spannable text, Layout layout) {
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int start = getSelectionStart(text);
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int end = getSelectionEnd(text);
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if (start != end) {
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int min = Math.min(start, end);
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int max = Math.max(start, end);
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setSelection(text, min);
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if (min == 0 && max == text.length()) {
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return false;
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}
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return true;
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} else {
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int line = layout.getLineForOffset(end);
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if (line > 0) {
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int move;
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if (layout.getParagraphDirection(line) ==
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layout.getParagraphDirection(line - 1)) {
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float h = layout.getPrimaryHorizontal(end);
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move = layout.getOffsetForHorizontal(line - 1, h);
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} else {
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move = layout.getLineStart(line - 1);
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}
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setSelection(text, move);
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return true;
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}
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}
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return false;
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}
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/**
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* Move the cursor to the buffer offset physically below the current
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* offset, or return false if the cursor is already on the bottom line.
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*/
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public static boolean moveDown(Spannable text, Layout layout) {
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int start = getSelectionStart(text);
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int end = getSelectionEnd(text);
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if (start != end) {
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int min = Math.min(start, end);
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int max = Math.max(start, end);
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setSelection(text, max);
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if (min == 0 && max == text.length()) {
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return false;
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}
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return true;
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} else {
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int line = layout.getLineForOffset(end);
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if (line < layout.getLineCount() - 1) {
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int move;
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if (layout.getParagraphDirection(line) ==
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layout.getParagraphDirection(line + 1)) {
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float h = layout.getPrimaryHorizontal(end);
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move = layout.getOffsetForHorizontal(line + 1, h);
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} else {
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move = layout.getLineStart(line + 1);
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}
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setSelection(text, move);
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return true;
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}
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}
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return false;
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}
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/**
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* Move the cursor to the buffer offset physically to the left of
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* the current offset, or return false if the cursor is already
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* at the left edge of the line and there is not another line to move it to.
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*/
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public static boolean moveLeft(Spannable text, Layout layout) {
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int start = getSelectionStart(text);
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int end = getSelectionEnd(text);
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if (start != end) {
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setSelection(text, chooseHorizontal(layout, -1, start, end));
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return true;
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} else {
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int to = layout.getOffsetToLeftOf(end);
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if (to != end) {
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setSelection(text, to);
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return true;
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}
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}
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return false;
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}
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/**
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* Move the cursor to the buffer offset physically to the right of
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* the current offset, or return false if the cursor is already at
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* at the right edge of the line and there is not another line
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* to move it to.
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*/
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public static boolean moveRight(Spannable text, Layout layout) {
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int start = getSelectionStart(text);
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int end = getSelectionEnd(text);
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if (start != end) {
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setSelection(text, chooseHorizontal(layout, 1, start, end));
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return true;
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} else {
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int to = layout.getOffsetToRightOf(end);
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if (to != end) {
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setSelection(text, to);
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return true;
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}
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}
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return false;
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}
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/**
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* Move the selection end to the buffer offset physically above
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* the current selection end.
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*/
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public static boolean extendUp(Spannable text, Layout layout) {
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int end = getSelectionEnd(text);
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int line = layout.getLineForOffset(end);
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if (line > 0) {
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int move;
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if (layout.getParagraphDirection(line) ==
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layout.getParagraphDirection(line - 1)) {
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float h = layout.getPrimaryHorizontal(end);
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move = layout.getOffsetForHorizontal(line - 1, h);
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} else {
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move = layout.getLineStart(line - 1);
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}
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extendSelection(text, move);
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return true;
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} else if (end != 0) {
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extendSelection(text, 0);
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return true;
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}
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return true;
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}
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/**
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* Move the selection end to the buffer offset physically below
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* the current selection end.
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*/
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public static boolean extendDown(Spannable text, Layout layout) {
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int end = getSelectionEnd(text);
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int line = layout.getLineForOffset(end);
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if (line < layout.getLineCount() - 1) {
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int move;
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if (layout.getParagraphDirection(line) ==
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layout.getParagraphDirection(line + 1)) {
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float h = layout.getPrimaryHorizontal(end);
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move = layout.getOffsetForHorizontal(line + 1, h);
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} else {
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move = layout.getLineStart(line + 1);
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}
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extendSelection(text, move);
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return true;
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} else if (end != text.length()) {
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extendSelection(text, text.length());
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return true;
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}
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return true;
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}
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/**
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* Move the selection end to the buffer offset physically to the left of
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* the current selection end.
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*/
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public static boolean extendLeft(Spannable text, Layout layout) {
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int end = getSelectionEnd(text);
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int to = layout.getOffsetToLeftOf(end);
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if (to != end) {
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extendSelection(text, to);
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return true;
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}
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return true;
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}
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/**
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* Move the selection end to the buffer offset physically to the right of
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* the current selection end.
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*/
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public static boolean extendRight(Spannable text, Layout layout) {
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int end = getSelectionEnd(text);
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int to = layout.getOffsetToRightOf(end);
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if (to != end) {
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extendSelection(text, to);
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return true;
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}
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return true;
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}
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public static boolean extendToLeftEdge(Spannable text, Layout layout) {
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int where = findEdge(text, layout, -1);
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extendSelection(text, where);
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return true;
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}
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public static boolean extendToRightEdge(Spannable text, Layout layout) {
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int where = findEdge(text, layout, 1);
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extendSelection(text, where);
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return true;
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}
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public static boolean moveToLeftEdge(Spannable text, Layout layout) {
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int where = findEdge(text, layout, -1);
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setSelection(text, where);
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return true;
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}
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public static boolean moveToRightEdge(Spannable text, Layout layout) {
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int where = findEdge(text, layout, 1);
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setSelection(text, where);
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return true;
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}
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private static int findEdge(Spannable text, Layout layout, int dir) {
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int pt = getSelectionEnd(text);
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int line = layout.getLineForOffset(pt);
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int pdir = layout.getParagraphDirection(line);
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if (dir * pdir < 0) {
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return layout.getLineStart(line);
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} else {
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int end = layout.getLineEnd(line);
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if (line == layout.getLineCount() - 1)
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return end;
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else
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return end - 1;
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}
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}
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private static int chooseHorizontal(Layout layout, int direction,
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int off1, int off2) {
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int line1 = layout.getLineForOffset(off1);
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int line2 = layout.getLineForOffset(off2);
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if (line1 == line2) {
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// same line, so it goes by pure physical direction
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float h1 = layout.getPrimaryHorizontal(off1);
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float h2 = layout.getPrimaryHorizontal(off2);
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if (direction < 0) {
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// to left
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if (h1 < h2)
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return off1;
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else
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return off2;
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} else {
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// to right
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if (h1 > h2)
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return off1;
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else
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return off2;
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}
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} else {
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// different line, so which line is "left" and which is "right"
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// depends upon the directionality of the text
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// This only checks at one end, but it's not clear what the
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// right thing to do is if the ends don't agree. Even if it
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// is wrong it should still not be too bad.
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int line = layout.getLineForOffset(off1);
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int textdir = layout.getParagraphDirection(line);
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if (textdir == direction)
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return Math.max(off1, off2);
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else
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return Math.min(off1, off2);
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}
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}
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private static final class START implements NoCopySpan { }
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private static final class END implements NoCopySpan { }
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/*
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* Public constants
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*/
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public static final Object SELECTION_START = new START();
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public static final Object SELECTION_END = new END();
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}
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