Try this way
public class MainActivity extends Activity {
String text;
EditText input;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
input =(EditText) findViewById(R.id.main_input);
}
public void clickme(View view) {
text= input.getText().toString();
Toast.makeText(MainActivity.this, text,Toast.LENGTH_LONG).show();
}
}
and change your onClick="clickme"
to your Button
in your activity_main.xml