1/*
2 * Copyright (C) 2011 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 com.android.contacts.common.format;
18
19import android.graphics.Typeface;
20import android.text.SpannableString;
21import android.text.style.CharacterStyle;
22import android.text.style.ForegroundColorSpan;
23import android.text.style.StyleSpan;
24import android.widget.TextView;
25
26import com.google.common.base.Preconditions;
27
28/**
29 * Highlights the text in a text field.
30 */
31public class TextHighlighter {
32    private final String TAG = TextHighlighter.class.getSimpleName();
33    private final static boolean DEBUG = false;
34
35    private int mTextStyle;
36
37    private CharacterStyle mTextStyleSpan;
38
39    public TextHighlighter(int textStyle) {
40        mTextStyle = textStyle;
41        mTextStyleSpan = getStyleSpan();
42    }
43
44    /**
45     * Sets the text on the given text view, highlighting the word that matches the given prefix.
46     *
47     * @param view the view on which to set the text
48     * @param text the string to use as the text
49     * @param prefix the prefix to look for
50     */
51    public void setPrefixText(TextView view, String text, String prefix) {
52        view.setText(applyPrefixHighlight(text, prefix));
53    }
54
55    private CharacterStyle getStyleSpan() {
56        return new StyleSpan(mTextStyle);
57    }
58
59    /**
60     * Applies highlight span to the text.
61     * @param text Text sequence to be highlighted.
62     * @param start Start position of the highlight sequence.
63     * @param end End position of the highlight sequence.
64     */
65    public void applyMaskingHighlight(SpannableString text, int start, int end) {
66        /** Sets text color of the masked locations to be highlighted. */
67        text.setSpan(getStyleSpan(), start, end, 0);
68    }
69
70    /**
71     * Returns a CharSequence which highlights the given prefix if found in the given text.
72     *
73     * @param text the text to which to apply the highlight
74     * @param prefix the prefix to look for
75     */
76    public CharSequence applyPrefixHighlight(CharSequence text, String prefix) {
77        if (prefix == null) {
78            return text;
79        }
80
81        // Skip non-word characters at the beginning of prefix.
82        int prefixStart = 0;
83        while (prefixStart < prefix.length() &&
84                !Character.isLetterOrDigit(prefix.charAt(prefixStart))) {
85            prefixStart++;
86        }
87        final String trimmedPrefix = prefix.substring(prefixStart);
88
89        int index = FormatUtils.indexOfWordPrefix(text, trimmedPrefix);
90        if (index != -1) {
91            final SpannableString result = new SpannableString(text);
92            result.setSpan(mTextStyleSpan, index, index + trimmedPrefix.length(), 0 /* flags */);
93            return result;
94        } else {
95            return text;
96        }
97    }
98}
99