android login via facebook. in android studio. Imageview as a button

I am new to android and i saw many login screen of app. they have image view as button like facebook and google. they set up imageview clicckable and try futher code. i have done the same but at the time of permission it ask me for button. it is not accepting imageview.setReadPermissions("user_friends"). how to make this corect. i am trying to login through facebook integration.

Following is my code:

public class MainActivity extends Activity {

    ImageView googleSignIn,facebooksignin,twittersignin;
    private CallbackManager mcallCallbackManger;

    TextView account;

    Context context=this;


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

        requestWindowFeature(Window.FEATURE_NO_TITLE);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                WindowManager.LayoutParams.FLAG_FULLSCREEN);
        setContentView(R.layout.activity_main);

        initialize();
        onclick();

        FacebookSdk.sdkInitialize(getApplicationContext());
        mcallCallbackManger = CallbackManager.Factory.create();
    }

    private FacebookCallback<LoginResult> mCallback=new FacebookCallback<LoginResult>() {
        @Override
        public void onSuccess(LoginResult loginResult) {

        }

        @Override
        public void onCancel() {

        }

        @Override
        public void onError(FacebookException error) {

        }
    };


    private void initialize(){
        googleSignIn=(ImageView)findViewById((R.id.googlesignin));
        facebooksignin=(ImageView)findViewById((R.id.facebooksignin));
        twittersignin=(ImageView)findViewById((R.id.twittersignin));
        account=(TextView)findViewById(R.id.account);

        permissions();

    }



    private void permissions(){

    }

    private void onclick(){

        googleSignIn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Snackbar snackbar = Snackbar
                        .make(v, "Clicked on google Sign In", Snackbar.LENGTH_LONG);

                snackbar.show();
            }
        });

        facebooksignin.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

            }

        });

        twittersignin.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Snackbar snackbar = Snackbar
                        .make(v, "Clicked on twitter Sign In", Snackbar.LENGTH_LONG);

                snackbar.show();
            }
        });

        account.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Snackbar snackbar = Snackbar
                        .make(v, "Clicked on account Sign In", Snackbar.LENGTH_LONG);

                snackbar.show();
            }
        });
    }

    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        mcallCallbackManger.onActivityResult(requestCode, resultCode, data);
    }

}