Java tutorial
/* * 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.method; import android.annotation.NonNull; import android.annotation.Nullable; import android.icu.text.DecimalFormatSymbols; import android.text.Editable; import android.text.InputFilter; import android.text.Selection; import android.text.Spannable; import android.text.SpannableStringBuilder; import android.text.Spanned; import android.text.format.DateFormat; import android.view.KeyEvent; import android.view.View; import libcore.icu.LocaleData; import java.util.Collection; import java.util.Locale; /** * For numeric text entry * <p></p> * As for all implementations of {@link KeyListener}, this class is only concerned * with hardware keyboards. Software input methods have no obligation to trigger * the methods in this class. */ public abstract class NumberKeyListener extends BaseKeyListener implements InputFilter { /** * You can say which characters you can accept. */ @NonNull protected abstract char[] getAcceptedChars(); protected int lookup(KeyEvent event, Spannable content) { return event.getMatch(getAcceptedChars(), getMetaState(content, event)); } public CharSequence filter(CharSequence source, int start, int end, Spanned dest, int dstart, int dend) { char[] accept = getAcceptedChars(); boolean filter = false; int i; for (i = start; i < end; i++) { if (!ok(accept, source.charAt(i))) { break; } } if (i == end) { // It was all OK. return null; } if (end - start == 1) { // It was not OK, and there is only one char, so nothing remains. return ""; } SpannableStringBuilder filtered = new SpannableStringBuilder(source, start, end); i -= start; end -= start; int len = end - start; // Only count down to i because the chars before that were all OK. for (int j = end - 1; j >= i; j--) { if (!ok(accept, source.charAt(j))) { filtered.delete(j, j + 1); } } return filtered; } protected static boolean ok(char[] accept, char c) { for (int i = accept.length - 1; i >= 0; i--) { if (accept[i] == c) { return true; } } return false; } @Override public boolean onKeyDown(View view, Editable content, int keyCode, KeyEvent event) { int selStart, selEnd; { int a = Selection.getSelectionStart(content); int b = Selection.getSelectionEnd(content); selStart = Math.min(a, b); selEnd = Math.max(a, b); } if (selStart < 0 || selEnd < 0) { selStart = selEnd = 0; Selection.setSelection(content, 0); } int i = event != null ? lookup(event, content) : 0; int repeatCount = event != null ? event.getRepeatCount() : 0; if (repeatCount == 0) { if (i != 0) { if (selStart != selEnd) { Selection.setSelection(content, selEnd); } content.replace(selStart, selEnd, String.valueOf((char) i)); adjustMetaAfterKeypress(content); return true; } } else if (i == '0' && repeatCount == 1) { // Pretty hackish, it replaces the 0 with the + if (selStart == selEnd && selEnd > 0 && content.charAt(selStart - 1) == '0') { content.replace(selStart - 1, selEnd, String.valueOf('+')); adjustMetaAfterKeypress(content); return true; } } adjustMetaAfterKeypress(content); return super.onKeyDown(view, content, keyCode, event); } /* package */ @Nullable static boolean addDigits(@NonNull Collection<Character> collection, @Nullable Locale locale) { if (locale == null) { return false; } final String[] digits = DecimalFormatSymbols.getInstance(locale).getDigitStrings(); for (int i = 0; i < 10; i++) { if (digits[i].length() > 1) { // multi-codeunit digits. Not supported. return false; } collection.add(Character.valueOf(digits[i].charAt(0))); } return true; } // From http://unicode.org/reports/tr35/tr35-dates.html#Date_Format_Patterns private static final String DATE_TIME_FORMAT_SYMBOLS = "GyYuUrQqMLlwWdDFgEecabBhHKkjJCmsSAzZOvVXx"; private static final char SINGLE_QUOTE = '\''; /* package */ static boolean addFormatCharsFromSkeleton(@NonNull Collection<Character> collection, @Nullable Locale locale, @NonNull String skeleton, @NonNull String symbolsToIgnore) { if (locale == null) { return false; } final String pattern = DateFormat.getBestDateTimePattern(locale, skeleton); boolean outsideQuotes = true; for (int i = 0; i < pattern.length(); i++) { final char ch = pattern.charAt(i); if (Character.isSurrogate(ch)) { // characters outside BMP are not supported. return false; } else if (ch == SINGLE_QUOTE) { outsideQuotes = !outsideQuotes; // Single quote characters should be considered if and only if they follow // another single quote. if (i == 0 || pattern.charAt(i - 1) != SINGLE_QUOTE) { continue; } } if (outsideQuotes) { if (symbolsToIgnore.indexOf(ch) != -1) { // Skip expected pattern characters. continue; } else if (DATE_TIME_FORMAT_SYMBOLS.indexOf(ch) != -1) { // An unexpected symbols is seen. We've failed. return false; } } // If we are here, we are either inside quotes, or we have seen a non-pattern // character outside quotes. So ch is a valid character in a date. collection.add(Character.valueOf(ch)); } return true; } /* package */ static boolean addFormatCharsFromSkeletons(@NonNull Collection<Character> collection, @Nullable Locale locale, @NonNull String[] skeletons, @NonNull String symbolsToIgnore) { for (int i = 0; i < skeletons.length; i++) { final boolean success = addFormatCharsFromSkeleton(collection, locale, skeletons[i], symbolsToIgnore); if (!success) { return false; } } return true; } /* package */ static boolean addAmPmChars(@NonNull Collection<Character> collection, @Nullable Locale locale) { if (locale == null) { return false; } final String[] amPm = LocaleData.get(locale).amPm; for (int i = 0; i < amPm.length; i++) { for (int j = 0; j < amPm[i].length(); j++) { final char ch = amPm[i].charAt(j); if (Character.isBmpCodePoint(ch)) { collection.add(Character.valueOf(ch)); } else { // We don't support non-BMP characters. return false; } } } return true; } /* package */ @NonNull static char[] collectionToArray(@NonNull Collection<Character> chars) { final char[] result = new char[chars.size()]; int i = 0; for (Character ch : chars) { result[i++] = ch; } return result; } }