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;
18
19/**
20 * When an object of a type is attached to an Editable, its methods will
21 * be called when the text is changed.
22 */
23public interface TextWatcher extends NoCopySpan {
24    /**
25     * This method is called to notify you that, within <code>s</code>,
26     * the <code>count</code> characters beginning at <code>start</code>
27     * are about to be replaced by new text with length <code>after</code>.
28     * It is an error to attempt to make changes to <code>s</code> from
29     * this callback.
30     */
31    public void beforeTextChanged(CharSequence s, int start,
32                                  int count, int after);
33    /**
34     * This method is called to notify you that, within <code>s</code>,
35     * the <code>count</code> characters beginning at <code>start</code>
36     * have just replaced old text that had length <code>before</code>.
37     * It is an error to attempt to make changes to <code>s</code> from
38     * this callback.
39     */
40    public void onTextChanged(CharSequence s, int start, int before, int count);
41
42    /**
43     * This method is called to notify you that, somewhere within
44     * <code>s</code>, the text has been changed.
45     * It is legitimate to make further changes to <code>s</code> from
46     * this callback, but be careful not to get yourself into an infinite
47     * loop, because any changes you make will cause this method to be
48     * called again recursively.
49     * (You are not told where the change took place because other
50     * afterTextChanged() methods may already have made other changes
51     * and invalidated the offsets.  But if you need to know here,
52     * you can use {@link Spannable#setSpan} in {@link #onTextChanged}
53     * to mark your place and then look up from here where the span
54     * ended up.
55     */
56    public void afterTextChanged(Editable s);
57}
58