648 lines
20 KiB
Java
648 lines
20 KiB
Java
/*
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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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import android.annotation.NonNull;
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import android.annotation.TestApi;
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import android.compat.annotation.UnsupportedAppUsage;
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import java.text.BreakIterator;
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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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}
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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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}
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return -1;
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}
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private static int getSelectionMemory(CharSequence text) {
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if (text instanceof Spanned) {
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return ((Spanned) text).getSpanStart(SELECTION_MEMORY);
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}
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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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setSelection(text, start, stop, -1);
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}
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/**
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* Set the selection anchor to <code>start</code>, the selection edge
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* to <code>stop</code> and the memory horizontal to <code>memory</code>.
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*/
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private static void setSelection(Spannable text, int start, int stop, int memory) {
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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, Spanned.SPAN_POINT_POINT);
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updateMemory(text, memory);
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}
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}
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/**
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* Update the memory position for text. This is used to ensure vertical navigation of lines
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* with different lengths behaves as expected and remembers the longest horizontal position
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* seen during a vertical traversal.
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*/
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private static void updateMemory(Spannable text, int memory) {
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if (memory > -1) {
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int currentMemory = getSelectionMemory(text);
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if (memory != currentMemory) {
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text.setSpan(SELECTION_MEMORY, memory, memory, Spanned.SPAN_POINT_POINT);
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if (currentMemory == -1) {
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// This is the first value, create a watcher.
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final TextWatcher watcher = new MemoryTextWatcher();
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text.setSpan(watcher, 0, text.length(), Spanned.SPAN_INCLUSIVE_INCLUSIVE);
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}
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}
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} else {
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removeMemory(text);
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}
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}
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private static void removeMemory(Spannable text) {
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text.removeSpan(SELECTION_MEMORY);
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MemoryTextWatcher[] watchers = text.getSpans(0, text.length(), MemoryTextWatcher.class);
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for (MemoryTextWatcher watcher : watchers) {
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text.removeSpan(watcher);
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}
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}
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/**
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* @hide
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*/
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@TestApi
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public static final class MemoryTextWatcher implements TextWatcher {
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@Override
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public void beforeTextChanged(CharSequence s, int start, int count, int after) {}
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@Override
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public void onTextChanged(CharSequence s, int start, int before, int count) {}
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@Override
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public void afterTextChanged(Editable s) {
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s.removeSpan(SELECTION_MEMORY);
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s.removeSpan(this);
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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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extendSelection(text, index, -1);
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}
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/**
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* Move the selection edge to offset <code>index</code> and update the memory horizontal.
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*/
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private static void extendSelection(Spannable text, int index, int memory) {
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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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updateMemory(text, memory);
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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, Spanned.SPAN_INTERMEDIATE);
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text.removeSpan(SELECTION_END);
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removeMemory(text);
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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, to the beginning if it is on the top line but not at the
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* start, 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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setSelectionAndMemory(
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text, layout, line, end, -1 /* direction */, false /* extend */);
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return true;
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} else if (end != 0) {
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setSelection(text, 0);
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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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* Calculate the movement and memory positions needed, and set or extend the selection.
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*/
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private static void setSelectionAndMemory(Spannable text, Layout layout, int line, int end,
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int direction, boolean extend) {
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int move;
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int newMemory;
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if (layout.getParagraphDirection(line)
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== layout.getParagraphDirection(line + direction)) {
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int memory = getSelectionMemory(text);
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if (memory > -1) {
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// We have a memory position
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float h = layout.getPrimaryHorizontal(memory);
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move = layout.getOffsetForHorizontal(line + direction, h);
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newMemory = memory;
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} else {
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// Create a new memory position
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float h = layout.getPrimaryHorizontal(end);
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move = layout.getOffsetForHorizontal(line + direction, h);
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newMemory = end;
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}
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} else {
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move = layout.getLineStart(line + direction);
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newMemory = -1;
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}
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if (extend) {
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extendSelection(text, move, newMemory);
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} else {
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setSelection(text, move, move, newMemory);
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}
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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, to the end of the buffer if it is on the bottom line but
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* not at the end, or return false if the cursor is already at the
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* end of the buffer.
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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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setSelectionAndMemory(
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text, layout, line, end, 1 /* direction */, false /* extend */);
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return true;
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} else if (end != text.length()) {
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setSelection(text, text.length());
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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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private static final char PARAGRAPH_SEPARATOR = '\n';
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/**
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* Move the cusrot to the closest paragraph start offset.
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*
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* @param text the spannable text
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* @param layout layout to be used for drawing.
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* @return true if the cursor is moved, otherwise false.
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*/
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public static boolean moveToParagraphStart(@NonNull Spannable text, @NonNull 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 = TextUtils.lastIndexOf(text, PARAGRAPH_SEPARATOR, start - 1);
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if (to == -1) {
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to = 0; // If not found, use the document start offset as a paragraph start.
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}
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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 closest paragraph end offset.
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*
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* @param text the spannable text
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* @param layout layout to be used for drawing.
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* @return true if the cursor is moved, otherwise false.
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*/
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public static boolean moveToParagraphEnd(@NonNull Spannable text, @NonNull 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 = TextUtils.indexOf(text, PARAGRAPH_SEPARATOR, end + 1);
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if (to == -1) {
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to = text.length();
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}
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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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* Extend the selection to the closest paragraph start offset.
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*
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* @param text the spannable text
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* @return true if the selection is extended, otherwise false
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*/
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public static boolean extendToParagraphStart(@NonNull Spannable text) {
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int end = getSelectionEnd(text);
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int to = TextUtils.lastIndexOf(text, PARAGRAPH_SEPARATOR, end - 1);
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if (to == -1) {
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to = 0; // If not found, use the document start offset as a paragraph start.
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}
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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 false;
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}
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/**
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* Extend the selection to the closest paragraph end offset.
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*
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* @param text the spannable text
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* @return true if the selection is extended, otherwise false
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*/
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public static boolean extendToParagraphEnd(@NonNull Spannable text) {
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int end = getSelectionEnd(text);
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int to = TextUtils.indexOf(text, PARAGRAPH_SEPARATOR, end + 1);
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if (to == -1) {
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to = text.length();
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}
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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 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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setSelectionAndMemory(text, layout, line, end, -1 /* direction */, true /* extend */);
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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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setSelectionAndMemory(text, layout, line, end, 1 /* direction */, true /* extend */);
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return true;
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} else if (end != text.length()) {
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extendSelection(text, text.length(), -1);
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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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/** {@hide} */
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public static interface PositionIterator {
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public static final int DONE = BreakIterator.DONE;
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public int preceding(int position);
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public int following(int position);
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}
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/** {@hide} */
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@UnsupportedAppUsage
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public static boolean moveToPreceding(
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Spannable text, PositionIterator iter, boolean extendSelection) {
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final int offset = iter.preceding(getSelectionEnd(text));
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if (offset != PositionIterator.DONE) {
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if (extendSelection) {
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extendSelection(text, offset);
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} else {
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setSelection(text, offset);
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}
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}
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return true;
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}
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/** {@hide} */
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@UnsupportedAppUsage
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public static boolean moveToFollowing(
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Spannable text, PositionIterator iter, boolean extendSelection) {
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final int offset = iter.following(getSelectionEnd(text));
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if (offset != PositionIterator.DONE) {
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if (extendSelection) {
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extendSelection(text, offset);
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} else {
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setSelection(text, offset);
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}
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}
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return true;
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}
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|
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();
|
|
}
|