Change android APP text font

Location of files

To properly store the font files you are going to use, they should be within the following location in your project:

/assets/fonts

You should already have /assets , missing the sub-folder /fonts .

File Formats

There are two supported formats TTF and OTF , the first one being most recommended for compatibility reasons, although both work.

Note:
The file and its extension must have lowercase letters:

minha_fonte.ttf (correcto)
minha_fonte.TTF (incorrecto)
minha_Fonte.ttf (incorrecto)
Museo.otf       (incorrecto) terá que ficar museo.otf

Create XML to name custom properties

The Android SDK allows you to name custom properties for your widgets , but you need to create an XML in the location below with the name attrs.xml :

/res/values

The XML to be created will have the following code:

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

Layout

We can now construct the layout which should be present in the file activity_main.xml at the location indicated below:

/res/layout/activity_main.xml

In this file we apply the following code:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:customfontdemo="http://schemas.android.com/apk/res-auto"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:orientation="vertical" 
  android:gravity="center">

 <TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textSize="24sp"
    android:padding="12dp"
    android:text="Fonte padrão do Android" />

  <com.authorwjf.customfontdemo.MyTextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textSize="32sp"
    android:padding="12dp"
    customfontdemo:minhaFonte="minha_fonte.ttf"
    android:text="A minha fonte no Android" />

</LinearLayout>

As you can see, we are already doing custom property fontName .

Class

You will now have to create a class below with the name MyTextView that will extend the default text view, and the file should be in the following location:

/src

With the name of the class we are creating:

/src/MyTextView.java

Containing the following code:

package com.authorwjf.customfontdemo;

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

public class MyTextView extends TextView {

  public MyTextView(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
    init(attrs);
  }

  public MyTextView(Context context, AttributeSet attrs) {
    super(context, attrs);
    init(attrs);
  }

  public MyTextView(Context context) {
    super(context);
    init(null);
  }

  private void init(AttributeSet attrs) {
    if (attrs!=null) {
      TypedArray a = getContext().obtainStyledAttributes(attrs, R.styleable.MyTextView);
      String minhaFonte = a.getString(R.styleable.MyTextView_minhaFonte);

      if (minhaFonte!=null) {
        Typeface myTypeface = Typeface.createFromAsset(getContext().getAssets(), "fonts/"+minhaFonte);
        setTypeface(myTypeface);
      }

      a.recycle();
    }
  }
}

Here we are collecting the font name of the custom attribute and applying typeface .

MainActivity.java

Since text view is in a standalone environment, we do not need to make modifications to the MainActivity.java file located in the folder below:

/src/MainActivity.java

Whose code will have the following code:

package com.authorwjf.customfontdemo;

import android.os.Bundle;
import android.app.Activity;

public class MainActivity extends Activity {

  @Override
    protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
    }
}