The following classes could not be instantiated: - com.facebook.widget.LoginButton

Question

I have been working on getting the facebook practice apps working and I cannot for the life of me figure out why I cannot reference the LoginButton found in the Facebook SDK

Answer 1

If you are use android studio then its clear documentation here,

Use facebook with fragment Tutorial

User facebook without fragment

Step 1 :Create java file MyApplication.java inside your package.

Tutorial

and copu myApplicatyon.java

Step 2 :setup androidmenufest.xml

Step 3 : Init inside activity where you are looking for init Login Button

    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    callbackManager = CallbackManager.Factory.create();
    FacebookSdk.sdkInitialize(getApplicationContext());
    setContentView(R.layout.activity_auth_login);

    //Init Elements
    etEmail = (EditText) findViewById(R.id.etEmail);
    etPassword = (EditText) findViewById(R.id.etPassword);

    validator = new Validator(this);
    validator.setValidationListener(this);

    serverConnection = new ServerConnection();

    //Faceboo login init
    loginButton = (LoginButton) findViewById(R.id.btnFbLogin);
    loginButton.setReadPermissions(Arrays.asList("public_profile","email","user_photos"));



    // Other app specific specialization
    // Callback registration
    loginButton.registerCallback(callbackManager, new FacebookCallback() {
        @Override
        public void onSuccess(LoginResult loginResult) {
            // App code

            Profile profile = Profile.getCurrentProfile();

            Log.v("profile.getName:",profile.getName());
        }

        @Override
        public void onCancel() {
            // App code
        }

        @Override
        public void onError(FacebookException exception) {
            // App code
        }
    });

}