Context

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);


        final Button button1 = (Button) findViewById(R.id.pairing);
        button1.setOnClickListener(new View.OnClickListener(){
            public void onClick(View v){

                Toasttest TT = new Toasttest(getApplicationContext());

            }
        });
    }

class Toasttest {

    public void Toasttest(Context CT){

        Toast.makeText(CT,"출력",Toast.LENGTH_LONG).show();

    }
}