customize Android Facebook Login button

In order to have completely custom facebook login button without using com.facebook.widget.LoginButton.

According to facebook sdk 4.x,

There new concept of login as from facebook

LoginManager and AccessToken – These new classes perform Facebook
Login

So, Now you can access Facebook authentication without Facebook login button as

layout.xml

    <Button
            android:id="@+id/btn_fb_login"
            .../>

MainActivity.java

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        FacebookSdk.sdkInitialize(this.getApplicationContext());

        callbackManager = CallbackManager.Factory.create();

        LoginManager.getInstance().registerCallback(callbackManager,
                new FacebookCallback<LoginResult>() {
                    @Override
                    public void onSuccess(LoginResult loginResult) {
                        Log.d("Success", "Login");

                    }

                    @Override
                    public void onCancel() {
                        Toast.makeText(MainActivity.this, "Login Cancel", Toast.LENGTH_LONG).show();
                    }

                    @Override
                    public void onError(FacebookException exception) {
                        Toast.makeText(MainActivity.this, exception.getMessage(), Toast.LENGTH_LONG).show();
                    }
                });

        setContentView(R.layout.activity_main);

        Button btn_fb_login = (Button)findViewById(R.id.btn_fb_login);

        btn_fb_login.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                  LoginManager.getInstance().logInWithReadPermissions(MainActivity.this, Arrays.asList("public_profile", "user_friends"));
            }
        });

    }

@Override 
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);

    callbackManager.onActivityResult(requestCode, resultCode, data); 
}