how to customize twitter login button

CannonballTwitterLoginButton.java

/**
 * Copyright (C) 2014 Twitter Inc and other contributors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package io.fabric.samples.cannonball.view;

import android.content.Context;
import android.util.AttributeSet;

import com.twitter.sdk.android.core.identity.TwitterLoginButton;

import io.fabric.samples.cannonball.App;
import io.fabric.samples.cannonball.R;

public class CannonballTwitterLoginButton extends TwitterLoginButton {
    public CannonballTwitterLoginButton(Context context) {
        super(context);
        init();
    }

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

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

    private void init() {
        if (isInEditMode()){
            return;
        }
        setCompoundDrawablesWithIntrinsicBounds(getResources().getDrawable(R.drawable
                .ic_signin_twitter), null, null, null);
        setBackgroundResource(R.drawable.sign_up_button);
        setTextSize(20);
        setPadding(30, 0, 10, 0);
        setTextColor(getResources().getColor(R.color.tw__blue_default));
        setTypeface(App.getInstance().getTypeface());
    }
}