| /* |
| * Copyright (C) 2008 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 com.android.calculator2; |
| |
| import android.text.SpannableStringBuilder; |
| import android.text.Editable; |
| |
| class CalculatorEditable extends SpannableStringBuilder { |
| private static final char[] ORIGINALS = {'-', '*', '/'}; |
| private static final char[] REPLACEMENTS = {'\u2212', '\u00d7', '\u00f7'}; |
| private boolean isInsideReplace = false; |
| private Logic mLogic; |
| |
| private CalculatorEditable(CharSequence source, Logic logic) { |
| super(source); |
| mLogic = logic; |
| } |
| |
| @Override |
| public SpannableStringBuilder |
| replace(int start, int end, CharSequence tb, int tbstart, int tbend) { |
| if (isInsideReplace) { |
| return super.replace(start, end, tb, tbstart, tbend); |
| } else { |
| isInsideReplace = true; |
| try { |
| String delta = tb.subSequence(tbstart, tbend).toString(); |
| return internalReplace(start, end, delta); |
| } finally { |
| isInsideReplace = false; |
| } |
| } |
| } |
| |
| private SpannableStringBuilder internalReplace(int start, int end, String delta) { |
| if (!mLogic.acceptInsert(delta)) { |
| mLogic.cleared(); |
| start = 0; |
| end = length(); |
| } |
| |
| for (int i = ORIGINALS.length - 1; i >= 0; --i) { |
| delta = delta.replace(ORIGINALS[i], REPLACEMENTS[i]); |
| } |
| |
| int length = delta.length(); |
| if (length == 1) { |
| char text = delta.charAt(0); |
| |
| //don't allow two dots in the same number |
| if (text == '.') { |
| int p = start - 1; |
| while (p >= 0 && Character.isDigit(charAt(p))) { |
| --p; |
| } |
| if (p >= 0 && charAt(p) == '.') { |
| return super.replace(start, end, ""); |
| } |
| } |
| |
| char prevChar = start > 0 ? charAt(start-1) : '\0'; |
| |
| //don't allow 2 successive minuses |
| if (text == Logic.MINUS && prevChar == Logic.MINUS) { |
| return super.replace(start, end, ""); |
| } |
| |
| //don't allow multiple successive operators |
| if (Logic.isOperator(text)) { |
| while (Logic.isOperator(prevChar) && |
| (text != Logic.MINUS || prevChar == '+')) { |
| --start; |
| prevChar = start > 0 ? charAt(start-1) : '\0'; |
| } |
| } |
| |
| //don't allow leading operator + * / |
| if (start == 0 && Logic.isOperator(text) && text != Logic.MINUS) { |
| return super.replace(start, end, ""); |
| } |
| } |
| return super.replace(start, end, delta); |
| } |
| |
| public static class Factory extends Editable.Factory { |
| private Logic mLogic; |
| |
| public Factory(Logic logic) { |
| mLogic = logic; |
| } |
| |
| public Editable newEditable(CharSequence source) { |
| return new CalculatorEditable(source, mLogic); |
| } |
| } |
| } |