Solution 1:

On Mobiletuts+ there is very good tutorial on Text formatting for Android. Quick Tip: Customize Android Fonts

EDIT: Tested it myself now. Here is the solution. You can use a subfolder called fonts but it must go in the assets folder not the res folder. So

assets/fonts

Also make sure that the font ending I mean the ending of the font file itself is all lower case. In other words it should not be myFont.TTF but myfont.ttf this way must be in lower case

Solution 2:

After trying most of the solutions described in this thread, I accidentally found Calligraphy (https://github.com/chrisjenx/Calligraphy) - a library by Christopher Jenkins that lets you easily add custom fonts to your app. The advantages of his lib comparing to approaches suggested here are:

  1. you don't have to introduce your own overriden TextView component, you use the built-in TextView
  2. you can easily include the library using gradle
  3. The library doesn't limit your choice of fonts; you just add your preferred ones to the assets dir
  4. you not only get custom text views — all the other text-based Android compontents will also be displayed using your custom font.

Solution 3:

I know there are good answers already, but here's a fully working implementation.

Here's the custom text view:

package com.mycompany.myapp.widget;

/**
 * Text view with a custom font.
 * <p/>
 * In the XML, use something like {@code customAttrs:customFont="roboto-thin"}. The list of fonts
 * that are currently supported are defined in the enum {@link CustomFont}. Remember to also add
 * {@code xmlns:customAttrs="http://schemas.android.com/apk/res-auto"} in the header.
 */
public class CustomFontTextView extends TextView {

    private static final String sScheme =
            "http://schemas.android.com/apk/res-auto";
    private static final String sAttribute = "customFont";

    static enum CustomFont {
        ROBOTO_THIN("fonts/Roboto-Thin.ttf"),
        ROBOTO_LIGHT("fonts/Roboto-Light.ttf");

        private final String fileName;

        CustomFont(String fileName) {
            this.fileName = fileName;
        }

        static CustomFont fromString(String fontName) {
            return CustomFont.valueOf(fontName.toUpperCase(Locale.US));
        }

        public Typeface asTypeface(Context context) {
            return Typeface.createFromAsset(context.getAssets(), fileName);
        }
    }

    public CustomFontTextView(Context context, AttributeSet attrs) {
        super(context, attrs);

        if (isInEditMode()) {
            return;
        } else {
            final String fontName = attrs.getAttributeValue(sScheme, sAttribute);

            if (fontName == null) {
                throw new IllegalArgumentException("You must provide \"" + sAttribute + "\" for your text view");
            } else {
                final Typeface customTypeface = CustomFont.fromString(fontName).asTypeface(context);
                setTypeface(customTypeface);
            }
        }
    }
}

Here's the custom attributes. This should go to your res/attrs.xml file:

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

And here's how you use it. I'll use a relative layout to wrap it and show the customAttr declaration, but it could obviously be whatever layout you already have.

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:customAttrs="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <com.mycompany.myapp.widget.CustomFontTextView
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:text="foobar"
         customAttrs:customFont="roboto_thin" />

</RelativeLayout>