1 /* 2 * Copyright (C) 2008 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 com.android.calculator2; 18 19 import android.text.SpannableStringBuilder; 20 import android.text.Editable; 21 22 class CalculatorEditable extends SpannableStringBuilder { 23 private static final char[] ORIGINALS = {'-', '*', '/'}; 24 private static final char[] REPLACEMENTS = {'\u2212', '\u00d7', '\u00f7'}; 25 private boolean isInsideReplace = false; 26 private Logic mLogic; 27 CalculatorEditable(CharSequence source, Logic logic)28 private CalculatorEditable(CharSequence source, Logic logic) { 29 super(source); 30 mLogic = logic; 31 } 32 33 @Override 34 public SpannableStringBuilder replace(int start, int end, CharSequence tb, int tbstart, int tbend)35 replace(int start, int end, CharSequence tb, int tbstart, int tbend) { 36 if (isInsideReplace) { 37 return super.replace(start, end, tb, tbstart, tbend); 38 } else { 39 isInsideReplace = true; 40 try { 41 String delta = tb.subSequence(tbstart, tbend).toString(); 42 return internalReplace(start, end, delta); 43 } finally { 44 isInsideReplace = false; 45 } 46 } 47 } 48 internalReplace(int start, int end, String delta)49 private SpannableStringBuilder internalReplace(int start, int end, String delta) { 50 if (!mLogic.acceptInsert(delta)) { 51 mLogic.cleared(); 52 start = 0; 53 end = length(); 54 } 55 56 for (int i = ORIGINALS.length - 1; i >= 0; --i) { 57 delta = delta.replace(ORIGINALS[i], REPLACEMENTS[i]); 58 } 59 60 int length = delta.length(); 61 if (length == 1) { 62 char text = delta.charAt(0); 63 64 //don't allow two dots in the same number 65 if (text == '.') { 66 int p = start - 1; 67 while (p >= 0 && Character.isDigit(charAt(p))) { 68 --p; 69 } 70 if (p >= 0 && charAt(p) == '.') { 71 return super.replace(start, end, ""); 72 } 73 } 74 75 char prevChar = start > 0 ? charAt(start-1) : '\0'; 76 77 //don't allow 2 successive minuses 78 if (text == Logic.MINUS && prevChar == Logic.MINUS) { 79 return super.replace(start, end, ""); 80 } 81 82 //don't allow multiple successive operators 83 if (Logic.isOperator(text)) { 84 while (Logic.isOperator(prevChar) && 85 (text != Logic.MINUS || prevChar == '+')) { 86 --start; 87 prevChar = start > 0 ? charAt(start-1) : '\0'; 88 } 89 } 90 91 //don't allow leading operator + * / 92 if (start == 0 && Logic.isOperator(text) && text != Logic.MINUS) { 93 return super.replace(start, end, ""); 94 } 95 } 96 return super.replace(start, end, delta); 97 } 98 99 public static class Factory extends Editable.Factory { 100 private Logic mLogic; 101 Factory(Logic logic)102 public Factory(Logic logic) { 103 mLogic = logic; 104 } 105 newEditable(CharSequence source)106 public Editable newEditable(CharSequence source) { 107 return new CalculatorEditable(source, mLogic); 108 } 109 } 110 } 111