activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin">

    <com.example.CustomView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="\uf1e2"
        android:textSize="60dp" />

    <com.example.TextViewWithFont
        xmlns:app="http://schemas.android.com/apk/res/com.example"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="\uf1e2"
        android:textSize="60dp"
        app:customFont="fontawesome-webfont.ttf" />
</LinearLayout>

attrs.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <declare-styleable name="TextViewPlusFont">
        <attr name="customFont" format="string"/>
    </declare-styleable>
</resources>

CustomView

package com.example;

import android.content.Context;
import android.util.AttributeSet;
import android.widget.TextView;

public class CustomView extends TextView{
    public CustomView(Context context) {
        this(context, null, 0);
    }

    public CustomView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public CustomView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        setTypeface(Typefaces.get(context, "fonts/fontawesome-webfont.ttf"));

    }
}

TextViewWithFont

package com.example;

import android.content.Context;
import android.content.res.TypedArray;
import android.util.AttributeSet;
import android.widget.TextView;

public class TextViewWithFont extends TextView {

    public TextViewWithFont(Context context) {
        super(context);
        init(context, null, 0);
    }
    public TextViewWithFont(Context context, AttributeSet attrs) {
        super(context, attrs);
        init(context, attrs, 0);
    }
    public TextViewWithFont(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        init(context, attrs, defStyle);
    }
    private void init(Context context, AttributeSet attrs, int defStyle) {
        // Load attributes
        TypedArray ta = context.obtainStyledAttributes(attrs, R.styleable.TextViewPlusFont, 0, 0);
        try {
            String fontInAssets = ta.getString(R.styleable.TextViewPlusFont_customFont);
            setTypeface(Typefaces.get(context, "fonts/"+ fontInAssets));
        } finally {
            ta.recycle();
        }
    }
}

Typefaces

package com.example.vestl_000.stackoverflow_voley;
import android.content.Context;
import android.graphics.Typeface;
import android.util.Log;
import java.util.Hashtable;

public class Typefaces {
    private static final String TAG = "Typefaces";

    private static final Hashtable<String, Typeface> cache = new Hashtable<String, Typeface>();

    public static Typeface get(Context c, String assetPath) {
        synchronized (cache) {
            if (!cache.containsKey(assetPath)) {
                try {
                    Typeface t = Typeface.createFromAsset(c.getAssets(),
                            assetPath);
                    cache.put(assetPath, t);
                    Log.e(TAG, "Loaded '" + assetPath);
                } catch (Exception e) {
                    Log.e(TAG, "Could not get typeface '" + assetPath
                            + "' because " + e.getMessage());
                    return null;
                }
            }
            return cache.get(assetPath);
        }
    }
}