Set Text size base on TypedValue

setTextSize (int unit, float size) set the default text size to a given unit and value. See TypedValue for the possible dimension units.

Example to set text size of TextView base on TypedValue:

MainActivity.java

package com.blogspot.android_er.androidfonts;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.TypedValue;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

    TextView text1, text2, text3, text4, text5, text6;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        text1 = (TextView)findViewById(R.id.text1);
        text2 = (TextView)findViewById(R.id.text2);
        text3 = (TextView)findViewById(R.id.text3);
        text4 = (TextView)findViewById(R.id.text4);
        text5 = (TextView)findViewById(R.id.text5);
        text6 = (TextView)findViewById(R.id.text6);

        text1.setTextSize(TypedValue.COMPLEX_UNIT_DIP, 20);
        text1.setText("20 DIP (Device Independent Pixels)");

        text2.setTextSize(TypedValue.COMPLEX_UNIT_IN, 0.5f);
        text2.setText("0.5 inch");

        text3.setTextSize(TypedValue.COMPLEX_UNIT_MM, 10);
        text3.setText("10 millimeter");

        text4.setTextSize(TypedValue.COMPLEX_UNIT_PT, 30);
        text4.setText("30 points");

        text5.setTextSize(TypedValue.COMPLEX_UNIT_PX, 30);
        text5.setText("30 raw pixels");

        text6.setTextSize(TypedValue.COMPLEX_UNIT_SP, 30);
        text6.setText("30 scaled pixels");
    }
}

layout/activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="16dp"
    android:orientation="vertical"
    tools:context="com.blogspot.android_er.androidfonts.MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:autoLink="web"
        android:text="http://android-er.blogspot.com/"
        android:textStyle="bold" />
    <TextView
        android:id="@+id/text1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
    <TextView
        android:id="@+id/text2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
    <TextView
        android:id="@+id/text3"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
    <TextView
        android:id="@+id/text4"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
    <TextView
        android:id="@+id/text5"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
    <TextView
        android:id="@+id/text6"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
</LinearLayout>