Android Help with Changing Button Font Type, How?

I use like this for button and it worked (same as for TextView) ..

 Button enter=(Button) findViewById(R.id.enter);
 Typeface type=Typeface.createFromAsset(getAssets(), "arial.ttf");
 enter.setTypeface(type);

hope it helps...

An other alternative for the above solutions:

mYourButton = (Button) findViewById(R.id.Button_id);
mYourEditText = (EditText) findViewById(R.id.editText_id);

Typeface font = ResourcesCompat.getFont(getContext(), R.font.font_name.TTF);
mYourButton.setTypeface(font);
mYourEditText.setTypeface(font);

If you plan to add the same font to several buttons I suggest that you go all the way and implement it as a style and subclass button:

public class ButtonPlus extends Button {

    public ButtonPlus(Context context) {
        super(context);
    }

    public ButtonPlus(Context context, AttributeSet attrs) {
        super(context, attrs);
        CustomFontHelper.setCustomFont(this, context, attrs);
    }

    public ButtonPlus(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        CustomFontHelper.setCustomFont(this, context, attrs);
    }
}

This is a helper class to set a font on a TextView (remember, Button is a subclass of TextView) based on the com.my.package:font attribute:

public class CustomFontHelper {

    /**
     * Sets a font on a textview based on the custom com.my.package:font attribute
     * If the custom font attribute isn't found in the attributes nothing happens
     * @param textview
     * @param context
     * @param attrs
     */
    public static void setCustomFont(TextView textview, Context context, AttributeSet attrs) {
        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.CustomFont);
        String font = a.getString(R.styleable.CustomFont_font);
        setCustomFont(textview, font, context);
        a.recycle();
    }

    /**
     * Sets a font on a textview
     * @param textview
     * @param font
     * @param context
     */
    public static void setCustomFont(TextView textview, String font, Context context) {
        if(font == null) {
            return;
        }
        Typeface tf = FontCache.get(font, context);
        if(tf != null) {
            textview.setTypeface(tf);
        }
    }
 }

And here's the FontCache to reduce memory usage on older devices:

public class FontCache {

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

    public static Typeface get(String name, Context context) {
        Typeface tf = fontCache.get(name);
        if(tf == null) {
            try {
                tf = Typeface.createFromAsset(context.getAssets(), name);
            }
            catch (Exception e) {
                return null;
            }
            fontCache.put(name, tf);
        }
        return tf;
    }
}

In res/values/attrs.xml we define the custom styleable attribute

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

And finally an example use in a layout:

<com.my.package.buttons.ButtonPlus
    style="@style/button"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/button_sometext"/>

And in res/values/style.xml

<style name="button" parent="@android:style/Widget.Button">
    <item name="com.my.package:font">fonts/copperplate_gothic_light.TTF</item>
</style>

This may seem like an awful lot of work, but you'll thank me once you have couple of handfuls of buttons and textfields that you want to change font on.

Button IS-A TextView, so just do it as with a TextView:

Button txt = (Button) findViewById(R.id.custom_font);  
Typeface font = Typeface.createFromAsset(getAssets(), "1543Humane_jenson_bold.TTF");  
txt.setTypeface(font);