how to scale font size for different screen size in android?

Scale font size for different support device

Different screen density using the following size scale:

• xxxhdpi: 4.0

• xxhdpi: 3.0

• xhdpi: 2.0
• hdpi: 1.5
• mdpi: 1.0 (baseline)
• ldpi: 0.75

A set of six generalized densities:

• ldpi (low) ~120dpi
• mdpi (medium) ~160dpi
• hdpi (high) ~240dpi
• xhdpi (extra-high) ~320dpi
• xxhdpi (extra-extra-high) ~480dpi
• xxxhdpi (extra-extra-extra-high) ~640dpi

Below function use for convert dp(Density indipendent pixel) to PX.

public static int dp2px(Context context, float dpValue) {
       final float scale = context.getResources().getDisplayMetrics().density;
       return (int) (dpValue * scale + 0.5f);
} 

Now We are going to set dynamic font size for all device 
Note: It will work only on the device, not on the tablet. we need to write different logic for the tablet.

textView.setTextSize(TypedValue.COMPLEX_UNIT_PX,dp2px(this,12f));

How It works on different screen.

• xxxhdpi: 4.0 =(12*4.0+0.5) =48.5

• xxhdpi: 3.0 =(12*3.0+0.5) =36.5

• xhdpi: 2.0 =(12*2.0+0.5) =24.5
• hdpi: 1.5 =(12*1.5+0.5) =18.5
• mdpi: 1.0 (baseline) =(12*1.0+0.5) =12.5
• ldpi: 0.75 =(12*0.75+0.5) =9.5

Reference links

http://developer.android.com/training/multiscreen/screendensities.html

http://developer.android.com/guide/practices/screens_support.html