TypefaceTextView.java

/*
 * TypefaceTextView.java
 * Simple
 *
 * Copyright 2012 Simple Finance Corporation (https://www.simple.com)
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *    http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.simple.widget;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Typeface;
import android.support.v4.util.LruCache;
import android.text.TextUtils;
import android.util.AttributeSet;
import android.widget.TextView;

import com.simple.R;

/**
 * <p>A custom <code>TextView</code> that displays text using a custom
 * <code>Typeface</code> that can be set in your XML layout.</p>
 * 
 * <p>To use the custom view attributes in your layout, you'll need to first
 * declare the custom namespace using the xmlns directive:</p>
 * 
 * <code><pre>
 *   &lt;?xml version="1.0" encoding="utf-8"?&gt;
 *   &lt;LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 *       xmlns:simple="http://schemas.android.com/apk/res/com.simple"
 *       android:layout_width="match_parent"
 *       android:layout_height="match_parent"
 *       android:orientation="vertical" &gt;
 *      
 *       &lt;com.simple.widget.TypefaceTextView
 *           android:layout_width="wrap_content"
 *           android:layout_height="wrap_content"
 *           simple:typeface="GothamMediumTabular"
 *           android:text="Hello, Gotham!" /&gt;
 *   
 *   &lt;/LinearLayout&gt;</pre></code>
 * 
 * <p>You can then set the typeface by providing the prefix of the desired
 * typeface file with the <code>simple:typeface</code> attribute.</p>
 * 
 * <p>Your typeface resources should be saved to the <code>assets/fonts</code>
 * directory of your project.</p>
 * 
 * <p>Files should include the suffix <code>-Family.otf</code>
 * (e.g. <code>GothamMediumTabular-Family.otf</code>).</p>
 * 
 * @author Tristan Waddington
 */
public class TypefaceTextView extends TextView {
    /** An <code>LruCache</code> for previously loaded typefaces. */
    private static LruCache<String, Typeface> sTypefaceCache =
            new LruCache<String, Typeface>(12);
    
    public TypefaceTextView(Context context, AttributeSet attrs) {
        super(context, attrs);
        
        // Get our custom attributes
        TypedArray a = context.getTheme().obtainStyledAttributes(attrs,
                R.styleable.TypefaceTextView, 0, 0);
        
        try {
            String typefaceName = a.getString(
                    R.styleable.TypefaceTextView_typeface);
            
            if (!isInEditMode() && !TextUtils.isEmpty(typefaceName)) {
                Typeface typeface = sTypefaceCache.get(typefaceName);
                
                if (typeface == null) {
                    typeface = Typeface.createFromAsset(context.getAssets(),
                            String.format("fonts/%s-Family.otf", typefaceName));
                    
                    // Cache the Typeface object
                    sTypefaceCache.put(typefaceName, typeface);
                }
                setTypeface(typeface);
                
                // Note: This flag is required for proper typeface rendering
                setPaintFlags(getPaintFlags() | Paint.SUBPIXEL_TEXT_FLAG);
            }
        } finally {
            a.recycle();
        }
    }
}