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.widget;
18
19
20import android.content.Context;
21import android.util.AttributeSet;
22import android.view.View;
23import android.view.ViewGroup;
24
25/**
26 * Specialized {@link android.widget.ViewSwitcher} that contains
27 * only children of type {@link android.widget.TextView}.
28 *
29 * A TextSwitcher is useful to animate a label on screen. Whenever
30 * {@link #setText(CharSequence)} is called, TextSwitcher animates the current text
31 * out and animates the new text in.
32 */
33public class TextSwitcher extends ViewSwitcher {
34    /**
35     * Creates a new empty TextSwitcher.
36     *
37     * @param context the application's environment
38     */
39    public TextSwitcher(Context context) {
40        super(context);
41    }
42
43    /**
44     * Creates a new empty TextSwitcher for the given context and with the
45     * specified set attributes.
46     *
47     * @param context the application environment
48     * @param attrs a collection of attributes
49     */
50    public TextSwitcher(Context context, AttributeSet attrs) {
51        super(context, attrs);
52    }
53
54    /**
55     * {@inheritDoc}
56     *
57     * @throws IllegalArgumentException if child is not an instance of
58     *         {@link android.widget.TextView}
59     */
60    @Override
61    public void addView(View child, int index, ViewGroup.LayoutParams params) {
62        if (!(child instanceof TextView)) {
63            throw new IllegalArgumentException(
64                    "TextSwitcher children must be instances of TextView");
65        }
66
67        super.addView(child, index, params);
68    }
69
70    /**
71     * Sets the text of the next view and switches to the next view. This can
72     * be used to animate the old text out and animate the next text in.
73     *
74     * @param text the new text to display
75     */
76    public void setText(CharSequence text) {
77        final TextView t = (TextView) getNextView();
78        t.setText(text);
79        showNext();
80    }
81
82    /**
83     * Sets the text of the text view that is currently showing.  This does
84     * not perform the animations.
85     *
86     * @param text the new text to display
87     */
88    public void setCurrentText(CharSequence text) {
89        ((TextView)getCurrentView()).setText(text);
90    }
91
92    @Override
93    public CharSequence getAccessibilityClassName() {
94        return TextSwitcher.class.getName();
95    }
96}
97