RadioButton

public class MainActivity extends AppCompatActivity {

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

        final RadioButton android, java, angular, python;
        android = (RadioButton)findViewById(R.id.rdbAndroid);
        angular = (RadioButton)findViewById(R.id.rdbAngular);
        java = (RadioButton)findViewById(R.id.rdbJava);
        python = (RadioButton)findViewById(R.id.rdbPython);
        Button btn = (Button)findViewById(R.id.getBtn);
        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String result = (android.isChecked())?"Android":(angular.isChecked())?"AngularJS":(java.isChecked())?"Java":(python.isChecked())?"Python":"";

                Toast.makeText(getApplicationContext(), "Tombol Radio = " + result , Toast.LENGTH_SHORT).show();
            }
        });
    }

    public void onRadioButtonClicked(View view) {
        boolean checked = ((RadioButton) view).isChecked();
        String str="";
        // Check which radio button was clicked
        switch(view.getId()) {
            case R.id.rdbAndroid:
                if(checked)
                    str = "Android Selected";
                break;
            case R.id.rdbAngular:
                if(checked)
                    str = "AngularJS Selected";
                break;
            case R.id.rdbJava:
                if(checked)
                    str = "Java Selected";
                break;
            case R.id.rdbPython:
                if(checked)
                    str = "Python Selected";
                break;
        }
        Toast.makeText(getApplicationContext(), str, Toast.LENGTH_SHORT).show();
    }
}