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
17package android.text.method;
18
19import android.view.KeyEvent;
20import android.view.View;
21import android.text.Editable;
22import android.text.InputFilter;
23import android.text.Selection;
24import android.text.Spannable;
25import android.text.SpannableStringBuilder;
26import android.text.Spanned;
27
28/**
29 * For numeric text entry
30 * <p></p>
31 * As for all implementations of {@link KeyListener}, this class is only concerned
32 * with hardware keyboards.  Software input methods have no obligation to trigger
33 * the methods in this class.
34 */
35public abstract class NumberKeyListener extends BaseKeyListener
36    implements InputFilter
37{
38    /**
39     * You can say which characters you can accept.
40     */
41    protected abstract char[] getAcceptedChars();
42
43    protected int lookup(KeyEvent event, Spannable content) {
44        return event.getMatch(getAcceptedChars(), getMetaState(content, event));
45    }
46
47    public CharSequence filter(CharSequence source, int start, int end,
48                               Spanned dest, int dstart, int dend) {
49        char[] accept = getAcceptedChars();
50        boolean filter = false;
51
52        int i;
53        for (i = start; i < end; i++) {
54            if (!ok(accept, source.charAt(i))) {
55                break;
56            }
57        }
58
59        if (i == end) {
60            // It was all OK.
61            return null;
62        }
63
64        if (end - start == 1) {
65            // It was not OK, and there is only one char, so nothing remains.
66            return "";
67        }
68
69        SpannableStringBuilder filtered =
70            new SpannableStringBuilder(source, start, end);
71        i -= start;
72        end -= start;
73
74        int len = end - start;
75        // Only count down to i because the chars before that were all OK.
76        for (int j = end - 1; j >= i; j--) {
77            if (!ok(accept, source.charAt(j))) {
78                filtered.delete(j, j + 1);
79            }
80        }
81
82        return filtered;
83    }
84
85    protected static boolean ok(char[] accept, char c) {
86        for (int i = accept.length - 1; i >= 0; i--) {
87            if (accept[i] == c) {
88                return true;
89            }
90        }
91
92        return false;
93    }
94
95    @Override
96    public boolean onKeyDown(View view, Editable content,
97                             int keyCode, KeyEvent event) {
98        int selStart, selEnd;
99
100        {
101            int a = Selection.getSelectionStart(content);
102            int b = Selection.getSelectionEnd(content);
103
104            selStart = Math.min(a, b);
105            selEnd = Math.max(a, b);
106        }
107
108        if (selStart < 0 || selEnd < 0) {
109            selStart = selEnd = 0;
110            Selection.setSelection(content, 0);
111        }
112
113        int i = event != null ? lookup(event, content) : 0;
114        int repeatCount = event != null ? event.getRepeatCount() : 0;
115        if (repeatCount == 0) {
116            if (i != 0) {
117                if (selStart != selEnd) {
118                    Selection.setSelection(content, selEnd);
119                }
120
121                content.replace(selStart, selEnd, String.valueOf((char) i));
122
123                adjustMetaAfterKeypress(content);
124                return true;
125            }
126        } else if (i == '0' && repeatCount == 1) {
127            // Pretty hackish, it replaces the 0 with the +
128
129            if (selStart == selEnd && selEnd > 0 &&
130                    content.charAt(selStart - 1) == '0') {
131                content.replace(selStart - 1, selEnd, String.valueOf('+'));
132                adjustMetaAfterKeypress(content);
133                return true;
134            }
135        }
136
137        adjustMetaAfterKeypress(content);
138        return super.onKeyDown(view, content, keyCode, event);
139    }
140}
141