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      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 
     17 package com.android.contacts.common.format;
     18 
     19 import android.graphics.Typeface;
     20 import android.text.SpannableString;
     21 import android.text.style.CharacterStyle;
     22 import android.text.style.ForegroundColorSpan;
     23 import android.text.style.StyleSpan;
     24 import android.widget.TextView;
     25 
     26 import com.google.common.base.Preconditions;
     27 
     28 /**
     29  * Highlights the text in a text field.
     30  */
     31 public 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