| /* |
| * Copyright (C) 2006 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 android.text; |
| |
| import android.annotation.TestApi; |
| |
| import java.text.BreakIterator; |
| |
| |
| /** |
| * Utility class for manipulating cursors and selections in CharSequences. |
| * A cursor is a selection where the start and end are at the same offset. |
| */ |
| public class Selection { |
| private Selection() { /* cannot be instantiated */ } |
| |
| /* |
| * Retrieving the selection |
| */ |
| |
| /** |
| * Return the offset of the selection anchor or cursor, or -1 if |
| * there is no selection or cursor. |
| */ |
| public static final int getSelectionStart(CharSequence text) { |
| if (text instanceof Spanned) { |
| return ((Spanned) text).getSpanStart(SELECTION_START); |
| } |
| return -1; |
| } |
| |
| /** |
| * Return the offset of the selection edge or cursor, or -1 if |
| * there is no selection or cursor. |
| */ |
| public static final int getSelectionEnd(CharSequence text) { |
| if (text instanceof Spanned) { |
| return ((Spanned) text).getSpanStart(SELECTION_END); |
| } |
| return -1; |
| } |
| |
| private static int getSelectionMemory(CharSequence text) { |
| if (text instanceof Spanned) { |
| return ((Spanned) text).getSpanStart(SELECTION_MEMORY); |
| } |
| return -1; |
| } |
| |
| /* |
| * Setting the selection |
| */ |
| |
| // private static int pin(int value, int min, int max) { |
| // return value < min ? 0 : (value > max ? max : value); |
| // } |
| |
| /** |
| * Set the selection anchor to <code>start</code> and the selection edge |
| * to <code>stop</code>. |
| */ |
| public static void setSelection(Spannable text, int start, int stop) { |
| setSelection(text, start, stop, -1); |
| } |
| |
| /** |
| * Set the selection anchor to <code>start</code>, the selection edge |
| * to <code>stop</code> and the memory horizontal to <code>memory</code>. |
| */ |
| private static void setSelection(Spannable text, int start, int stop, int memory) { |
| // int len = text.length(); |
| // start = pin(start, 0, len); XXX remove unless we really need it |
| // stop = pin(stop, 0, len); |
| |
| int ostart = getSelectionStart(text); |
| int oend = getSelectionEnd(text); |
| |
| if (ostart != start || oend != stop) { |
| text.setSpan(SELECTION_START, start, start, |
| Spanned.SPAN_POINT_POINT | Spanned.SPAN_INTERMEDIATE); |
| text.setSpan(SELECTION_END, stop, stop, Spanned.SPAN_POINT_POINT); |
| updateMemory(text, memory); |
| } |
| } |
| |
| /** |
| * Update the memory position for text. This is used to ensure vertical navigation of lines |
| * with different lengths behaves as expected and remembers the longest horizontal position |
| * seen during a vertical traversal. |
| */ |
| private static void updateMemory(Spannable text, int memory) { |
| if (memory > -1) { |
| int currentMemory = getSelectionMemory(text); |
| if (memory != currentMemory) { |
| text.setSpan(SELECTION_MEMORY, memory, memory, Spanned.SPAN_POINT_POINT); |
| if (currentMemory == -1) { |
| // This is the first value, create a watcher. |
| final TextWatcher watcher = new MemoryTextWatcher(); |
| text.setSpan(watcher, 0, text.length(), Spanned.SPAN_INCLUSIVE_INCLUSIVE); |
| } |
| } |
| } else { |
| removeMemory(text); |
| } |
| } |
| |
| private static void removeMemory(Spannable text) { |
| text.removeSpan(SELECTION_MEMORY); |
| MemoryTextWatcher[] watchers = text.getSpans(0, text.length(), MemoryTextWatcher.class); |
| for (MemoryTextWatcher watcher : watchers) { |
| text.removeSpan(watcher); |
| } |
| } |
| |
| /** |
| * @hide |
| */ |
| @TestApi |
| public static final class MemoryTextWatcher implements TextWatcher { |
| |
| @Override |
| public void beforeTextChanged(CharSequence s, int start, int count, int after) {} |
| |
| @Override |
| public void onTextChanged(CharSequence s, int start, int before, int count) {} |
| |
| @Override |
| public void afterTextChanged(Editable s) { |
| s.removeSpan(SELECTION_MEMORY); |
| s.removeSpan(this); |
| } |
| } |
| |
| /** |
| * Move the cursor to offset <code>index</code>. |
| */ |
| public static final void setSelection(Spannable text, int index) { |
| setSelection(text, index, index); |
| } |
| |
| /** |
| * Select the entire text. |
| */ |
| public static final void selectAll(Spannable text) { |
| setSelection(text, 0, text.length()); |
| } |
| |
| /** |
| * Move the selection edge to offset <code>index</code>. |
| */ |
| public static final void extendSelection(Spannable text, int index) { |
| extendSelection(text, index, -1); |
| } |
| |
| /** |
| * Move the selection edge to offset <code>index</code> and update the memory horizontal. |
| */ |
| private static void extendSelection(Spannable text, int index, int memory) { |
| if (text.getSpanStart(SELECTION_END) != index) { |
| text.setSpan(SELECTION_END, index, index, Spanned.SPAN_POINT_POINT); |
| } |
| updateMemory(text, memory); |
| } |
| |
| /** |
| * Remove the selection or cursor, if any, from the text. |
| */ |
| public static final void removeSelection(Spannable text) { |
| text.removeSpan(SELECTION_START, Spanned.SPAN_INTERMEDIATE); |
| text.removeSpan(SELECTION_END); |
| removeMemory(text); |
| } |
| |
| /* |
| * Moving the selection within the layout |
| */ |
| |
| /** |
| * Move the cursor to the buffer offset physically above the current |
| * offset, to the beginning if it is on the top line but not at the |
| * start, or return false if the cursor is already on the top line. |
| */ |
| public static boolean moveUp(Spannable text, Layout layout) { |
| int start = getSelectionStart(text); |
| int end = getSelectionEnd(text); |
| |
| if (start != end) { |
| int min = Math.min(start, end); |
| int max = Math.max(start, end); |
| |
| setSelection(text, min); |
| |
| if (min == 0 && max == text.length()) { |
| return false; |
| } |
| |
| return true; |
| } else { |
| int line = layout.getLineForOffset(end); |
| |
| if (line > 0) { |
| setSelectionAndMemory( |
| text, layout, line, end, -1 /* direction */, false /* extend */); |
| return true; |
| } else if (end != 0) { |
| setSelection(text, 0); |
| return true; |
| } |
| } |
| |
| return false; |
| } |
| |
| /** |
| * Calculate the movement and memory positions needed, and set or extend the selection. |
| */ |
| private static void setSelectionAndMemory(Spannable text, Layout layout, int line, int end, |
| int direction, boolean extend) { |
| int move; |
| int newMemory; |
| |
| if (layout.getParagraphDirection(line) |
| == layout.getParagraphDirection(line + direction)) { |
| int memory = getSelectionMemory(text); |
| if (memory > -1) { |
| // We have a memory position |
| float h = layout.getPrimaryHorizontal(memory); |
| move = layout.getOffsetForHorizontal(line + direction, h); |
| newMemory = memory; |
| } else { |
| // Create a new memory position |
| float h = layout.getPrimaryHorizontal(end); |
| move = layout.getOffsetForHorizontal(line + direction, h); |
| newMemory = end; |
| } |
| } else { |
| move = layout.getLineStart(line + direction); |
| newMemory = -1; |
| } |
| |
| if (extend) { |
| extendSelection(text, move, newMemory); |
| } else { |
| setSelection(text, move, move, newMemory); |
| } |
| } |
| |
| /** |
| * Move the cursor to the buffer offset physically below the current |
| * offset, to the end of the buffer if it is on the bottom line but |
| * not at the end, or return false if the cursor is already at the |
| * end of the buffer. |
| */ |
| public static boolean moveDown(Spannable text, Layout layout) { |
| int start = getSelectionStart(text); |
| int end = getSelectionEnd(text); |
| |
| if (start != end) { |
| int min = Math.min(start, end); |
| int max = Math.max(start, end); |
| |
| setSelection(text, max); |
| |
| if (min == 0 && max == text.length()) { |
| return false; |
| } |
| |
| return true; |
| } else { |
| int line = layout.getLineForOffset(end); |
| |
| if (line < layout.getLineCount() - 1) { |
| setSelectionAndMemory( |
| text, layout, line, end, 1 /* direction */, false /* extend */); |
| return true; |
| } else if (end != text.length()) { |
| setSelection(text, text.length()); |
| return true; |
| } |
| } |
| |
| return false; |
| } |
| |
| /** |
| * Move the cursor to the buffer offset physically to the left of |
| * the current offset, or return false if the cursor is already |
| * at the left edge of the line and there is not another line to move it to. |
| */ |
| public static boolean moveLeft(Spannable text, Layout layout) { |
| int start = getSelectionStart(text); |
| int end = getSelectionEnd(text); |
| |
| if (start != end) { |
| setSelection(text, chooseHorizontal(layout, -1, start, end)); |
| return true; |
| } else { |
| int to = layout.getOffsetToLeftOf(end); |
| |
| if (to != end) { |
| setSelection(text, to); |
| return true; |
| } |
| } |
| |
| return false; |
| } |
| |
| /** |
| * Move the cursor to the buffer offset physically to the right of |
| * the current offset, or return false if the cursor is already at |
| * at the right edge of the line and there is not another line |
| * to move it to. |
| */ |
| public static boolean moveRight(Spannable text, Layout layout) { |
| int start = getSelectionStart(text); |
| int end = getSelectionEnd(text); |
| |
| if (start != end) { |
| setSelection(text, chooseHorizontal(layout, 1, start, end)); |
| return true; |
| } else { |
| int to = layout.getOffsetToRightOf(end); |
| |
| if (to != end) { |
| setSelection(text, to); |
| return true; |
| } |
| } |
| |
| return false; |
| } |
| |
| /** |
| * Move the selection end to the buffer offset physically above |
| * the current selection end. |
| */ |
| public static boolean extendUp(Spannable text, Layout layout) { |
| int end = getSelectionEnd(text); |
| int line = layout.getLineForOffset(end); |
| |
| if (line > 0) { |
| setSelectionAndMemory(text, layout, line, end, -1 /* direction */, true /* extend */); |
| return true; |
| } else if (end != 0) { |
| extendSelection(text, 0); |
| return true; |
| } |
| |
| return true; |
| } |
| |
| /** |
| * Move the selection end to the buffer offset physically below |
| * the current selection end. |
| */ |
| public static boolean extendDown(Spannable text, Layout layout) { |
| int end = getSelectionEnd(text); |
| int line = layout.getLineForOffset(end); |
| |
| if (line < layout.getLineCount() - 1) { |
| setSelectionAndMemory(text, layout, line, end, 1 /* direction */, true /* extend */); |
| return true; |
| } else if (end != text.length()) { |
| extendSelection(text, text.length(), -1); |
| return true; |
| } |
| |
| return true; |
| } |
| |
| /** |
| * Move the selection end to the buffer offset physically to the left of |
| * the current selection end. |
| */ |
| public static boolean extendLeft(Spannable text, Layout layout) { |
| int end = getSelectionEnd(text); |
| int to = layout.getOffsetToLeftOf(end); |
| |
| if (to != end) { |
| extendSelection(text, to); |
| return true; |
| } |
| |
| return true; |
| } |
| |
| /** |
| * Move the selection end to the buffer offset physically to the right of |
| * the current selection end. |
| */ |
| public static boolean extendRight(Spannable text, Layout layout) { |
| int end = getSelectionEnd(text); |
| int to = layout.getOffsetToRightOf(end); |
| |
| if (to != end) { |
| extendSelection(text, to); |
| return true; |
| } |
| |
| return true; |
| } |
| |
| public static boolean extendToLeftEdge(Spannable text, Layout layout) { |
| int where = findEdge(text, layout, -1); |
| extendSelection(text, where); |
| return true; |
| } |
| |
| public static boolean extendToRightEdge(Spannable text, Layout layout) { |
| int where = findEdge(text, layout, 1); |
| extendSelection(text, where); |
| return true; |
| } |
| |
| public static boolean moveToLeftEdge(Spannable text, Layout layout) { |
| int where = findEdge(text, layout, -1); |
| setSelection(text, where); |
| return true; |
| } |
| |
| public static boolean moveToRightEdge(Spannable text, Layout layout) { |
| int where = findEdge(text, layout, 1); |
| setSelection(text, where); |
| return true; |
| } |
| |
| /** {@hide} */ |
| public static interface PositionIterator { |
| public static final int DONE = BreakIterator.DONE; |
| |
| public int preceding(int position); |
| public int following(int position); |
| } |
| |
| /** {@hide} */ |
| public static boolean moveToPreceding( |
| Spannable text, PositionIterator iter, boolean extendSelection) { |
| final int offset = iter.preceding(getSelectionEnd(text)); |
| if (offset != PositionIterator.DONE) { |
| if (extendSelection) { |
| extendSelection(text, offset); |
| } else { |
| setSelection(text, offset); |
| } |
| } |
| return true; |
| } |
| |
| /** {@hide} */ |
| public static boolean moveToFollowing( |
| Spannable text, PositionIterator iter, boolean extendSelection) { |
| final int offset = iter.following(getSelectionEnd(text)); |
| if (offset != PositionIterator.DONE) { |
| if (extendSelection) { |
| extendSelection(text, offset); |
| } else { |
| setSelection(text, offset); |
| } |
| } |
| return true; |
| } |
| |
| private static int findEdge(Spannable text, Layout layout, int dir) { |
| int pt = getSelectionEnd(text); |
| int line = layout.getLineForOffset(pt); |
| int pdir = layout.getParagraphDirection(line); |
| |
| if (dir * pdir < 0) { |
| return layout.getLineStart(line); |
| } else { |
| int end = layout.getLineEnd(line); |
| |
| if (line == layout.getLineCount() - 1) |
| return end; |
| else |
| return end - 1; |
| } |
| } |
| |
| private static int chooseHorizontal(Layout layout, int direction, |
| int off1, int off2) { |
| int line1 = layout.getLineForOffset(off1); |
| int line2 = layout.getLineForOffset(off2); |
| |
| if (line1 == line2) { |
| // same line, so it goes by pure physical direction |
| |
| float h1 = layout.getPrimaryHorizontal(off1); |
| float h2 = layout.getPrimaryHorizontal(off2); |
| |
| if (direction < 0) { |
| // to left |
| |
| if (h1 < h2) |
| return off1; |
| else |
| return off2; |
| } else { |
| // to right |
| |
| if (h1 > h2) |
| return off1; |
| else |
| return off2; |
| } |
| } else { |
| // different line, so which line is "left" and which is "right" |
| // depends upon the directionality of the text |
| |
| // This only checks at one end, but it's not clear what the |
| // right thing to do is if the ends don't agree. Even if it |
| // is wrong it should still not be too bad. |
| int line = layout.getLineForOffset(off1); |
| int textdir = layout.getParagraphDirection(line); |
| |
| if (textdir == direction) |
| return Math.max(off1, off2); |
| else |
| return Math.min(off1, off2); |
| } |
| } |
| |
| private static final class START implements NoCopySpan { } |
| private static final class END implements NoCopySpan { } |
| private static final class MEMORY implements NoCopySpan { } |
| private static final Object SELECTION_MEMORY = new MEMORY(); |
| |
| /* |
| * Public constants |
| */ |
| |
| public static final Object SELECTION_START = new START(); |
| public static final Object SELECTION_END = new END(); |
| } |