The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2006 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package android.text; |
| 18 | |
Roozbeh Pournader | 4e5e15a | 2017-08-01 19:30:28 -0700 | [diff] [blame] | 19 | import android.annotation.NonNull; |
Mathew Inwood | efeab84 | 2018-08-14 15:21:30 +0100 | [diff] [blame] | 20 | import android.annotation.UnsupportedAppUsage; |
Roozbeh Pournader | 4e5e15a | 2017-08-01 19:30:28 -0700 | [diff] [blame] | 21 | |
| 22 | import com.android.internal.util.Preconditions; |
Roozbeh Pournader | 205a993 | 2017-06-08 00:23:42 -0700 | [diff] [blame] | 23 | |
| 24 | import java.util.Locale; |
| 25 | |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 26 | /** |
| 27 | * InputFilters can be attached to {@link Editable}s to constrain the |
| 28 | * changes that can be made to them. |
| 29 | */ |
| 30 | public interface InputFilter |
| 31 | { |
| 32 | /** |
| 33 | * This method is called when the buffer is going to replace the |
| 34 | * range <code>dstart … dend</code> of <code>dest</code> |
| 35 | * with the new text from the range <code>start … end</code> |
| 36 | * of <code>source</code>. Return the CharSequence that you would |
| 37 | * like to have placed there instead, including an empty string |
| 38 | * if appropriate, or <code>null</code> to accept the original |
| 39 | * replacement. Be careful to not to reject 0-length replacements, |
| 40 | * as this is what happens when you delete text. Also beware that |
| 41 | * you should not attempt to make any changes to <code>dest</code> |
| 42 | * from this method; you may only examine it for context. |
Roozbeh Pournader | 205a993 | 2017-06-08 00:23:42 -0700 | [diff] [blame] | 43 | * |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 44 | * Note: If <var>source</var> is an instance of {@link Spanned} or |
Roozbeh Pournader | 205a993 | 2017-06-08 00:23:42 -0700 | [diff] [blame] | 45 | * {@link Spannable}, the span objects in the <var>source</var> should be |
| 46 | * copied into the filtered result (i.e. the non-null return value). |
| 47 | * {@link TextUtils#copySpansFrom} can be used for convenience if the |
| 48 | * span boundary indices would be remaining identical relative to the source. |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 49 | */ |
| 50 | public CharSequence filter(CharSequence source, int start, int end, |
| 51 | Spanned dest, int dstart, int dend); |
| 52 | |
| 53 | /** |
Roozbeh Pournader | 205a993 | 2017-06-08 00:23:42 -0700 | [diff] [blame] | 54 | * This filter will capitalize all the lowercase and titlecase letters that are added |
| 55 | * through edits. (Note that if there are no lowercase or titlecase letters in the input, the |
| 56 | * text would not be transformed, even if the result of capitalization of the string is |
| 57 | * different from the string.) |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 58 | */ |
| 59 | public static class AllCaps implements InputFilter { |
Roozbeh Pournader | 205a993 | 2017-06-08 00:23:42 -0700 | [diff] [blame] | 60 | private final Locale mLocale; |
| 61 | |
| 62 | public AllCaps() { |
| 63 | mLocale = null; |
| 64 | } |
| 65 | |
| 66 | /** |
| 67 | * Constructs a locale-specific AllCaps filter, to make sure capitalization rules of that |
| 68 | * locale are used for transforming the sequence. |
| 69 | */ |
Roozbeh Pournader | 4e5e15a | 2017-08-01 19:30:28 -0700 | [diff] [blame] | 70 | public AllCaps(@NonNull Locale locale) { |
| 71 | Preconditions.checkNotNull(locale); |
Roozbeh Pournader | 205a993 | 2017-06-08 00:23:42 -0700 | [diff] [blame] | 72 | mLocale = locale; |
| 73 | } |
| 74 | |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 75 | public CharSequence filter(CharSequence source, int start, int end, |
| 76 | Spanned dest, int dstart, int dend) { |
Roozbeh Pournader | 205a993 | 2017-06-08 00:23:42 -0700 | [diff] [blame] | 77 | final CharSequence wrapper = new CharSequenceWrapper(source, start, end); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 78 | |
Roozbeh Pournader | 205a993 | 2017-06-08 00:23:42 -0700 | [diff] [blame] | 79 | boolean lowerOrTitleFound = false; |
| 80 | final int length = end - start; |
| 81 | for (int i = 0, cp; i < length; i += Character.charCount(cp)) { |
| 82 | // We access 'wrapper' instead of 'source' to make sure no code unit beyond 'end' is |
| 83 | // ever accessed. |
| 84 | cp = Character.codePointAt(wrapper, i); |
| 85 | if (Character.isLowerCase(cp) || Character.isTitleCase(cp)) { |
| 86 | lowerOrTitleFound = true; |
| 87 | break; |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 88 | } |
| 89 | } |
Roozbeh Pournader | 205a993 | 2017-06-08 00:23:42 -0700 | [diff] [blame] | 90 | if (!lowerOrTitleFound) { |
| 91 | return null; // keep original |
| 92 | } |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 93 | |
Roozbeh Pournader | 205a993 | 2017-06-08 00:23:42 -0700 | [diff] [blame] | 94 | final boolean copySpans = source instanceof Spanned; |
| 95 | final CharSequence upper = TextUtils.toUpperCase(mLocale, wrapper, copySpans); |
| 96 | if (upper == wrapper) { |
| 97 | // Nothing was changed in the uppercasing operation. This is weird, since |
| 98 | // we had found at least one lowercase or titlecase character. But we can't |
| 99 | // do anything better than keeping the original in this case. |
| 100 | return null; // keep original |
| 101 | } |
| 102 | // Return a SpannableString or String for backward compatibility. |
| 103 | return copySpans ? new SpannableString(upper) : upper.toString(); |
| 104 | } |
| 105 | |
| 106 | private static class CharSequenceWrapper implements CharSequence, Spanned { |
| 107 | private final CharSequence mSource; |
| 108 | private final int mStart, mEnd; |
| 109 | private final int mLength; |
| 110 | |
| 111 | CharSequenceWrapper(CharSequence source, int start, int end) { |
| 112 | mSource = source; |
| 113 | mStart = start; |
| 114 | mEnd = end; |
| 115 | mLength = end - start; |
| 116 | } |
| 117 | |
| 118 | public int length() { |
| 119 | return mLength; |
| 120 | } |
| 121 | |
| 122 | public char charAt(int index) { |
| 123 | if (index < 0 || index >= mLength) { |
| 124 | throw new IndexOutOfBoundsException(); |
| 125 | } |
| 126 | return mSource.charAt(mStart + index); |
| 127 | } |
| 128 | |
| 129 | public CharSequence subSequence(int start, int end) { |
| 130 | if (start < 0 || end < 0 || end > mLength || start > end) { |
| 131 | throw new IndexOutOfBoundsException(); |
| 132 | } |
| 133 | return new CharSequenceWrapper(mSource, mStart + start, mStart + end); |
| 134 | } |
| 135 | |
| 136 | public String toString() { |
| 137 | return mSource.subSequence(mStart, mEnd).toString(); |
| 138 | } |
| 139 | |
| 140 | public <T> T[] getSpans(int start, int end, Class<T> type) { |
| 141 | return ((Spanned) mSource).getSpans(mStart + start, mStart + end, type); |
| 142 | } |
| 143 | |
| 144 | public int getSpanStart(Object tag) { |
| 145 | return ((Spanned) mSource).getSpanStart(tag) - mStart; |
| 146 | } |
| 147 | |
| 148 | public int getSpanEnd(Object tag) { |
| 149 | return ((Spanned) mSource).getSpanEnd(tag) - mStart; |
| 150 | } |
| 151 | |
| 152 | public int getSpanFlags(Object tag) { |
| 153 | return ((Spanned) mSource).getSpanFlags(tag); |
| 154 | } |
| 155 | |
| 156 | public int nextSpanTransition(int start, int limit, Class type) { |
| 157 | return ((Spanned) mSource).nextSpanTransition(mStart + start, mStart + limit, type) |
| 158 | - mStart; |
| 159 | } |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 160 | } |
| 161 | } |
| 162 | |
| 163 | /** |
| 164 | * This filter will constrain edits not to make the length of the text |
| 165 | * greater than the specified length. |
| 166 | */ |
| 167 | public static class LengthFilter implements InputFilter { |
Mathew Inwood | efeab84 | 2018-08-14 15:21:30 +0100 | [diff] [blame] | 168 | @UnsupportedAppUsage |
Alan Viverette | 029942f | 2014-08-12 14:55:56 -0700 | [diff] [blame] | 169 | private final int mMax; |
| 170 | |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 171 | public LengthFilter(int max) { |
| 172 | mMax = max; |
| 173 | } |
| 174 | |
Alan Viverette | 029942f | 2014-08-12 14:55:56 -0700 | [diff] [blame] | 175 | public CharSequence filter(CharSequence source, int start, int end, Spanned dest, |
| 176 | int dstart, int dend) { |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 177 | int keep = mMax - (dest.length() - (dend - dstart)); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 178 | if (keep <= 0) { |
| 179 | return ""; |
| 180 | } else if (keep >= end - start) { |
| 181 | return null; // keep original |
| 182 | } else { |
Ishibashi Takako | 2f0f442 | 2010-11-04 08:43:33 +0100 | [diff] [blame] | 183 | keep += start; |
| 184 | if (Character.isHighSurrogate(source.charAt(keep - 1))) { |
| 185 | --keep; |
| 186 | if (keep == start) { |
| 187 | return ""; |
| 188 | } |
| 189 | } |
| 190 | return source.subSequence(start, keep); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 191 | } |
| 192 | } |
| 193 | |
Alan Viverette | 029942f | 2014-08-12 14:55:56 -0700 | [diff] [blame] | 194 | /** |
| 195 | * @return the maximum length enforced by this input filter |
| 196 | */ |
| 197 | public int getMax() { |
| 198 | return mMax; |
| 199 | } |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 200 | } |
| 201 | } |