andorid_custom_event.java

public class MainActivity extends Activity {

    final static int USER_EVENT = 1000;
    Handler handler;

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

        Button btnMakeEvent = (Button) findViewById(R.id.btn);
        final EditText etInput = (EditText) findViewById(R.id.et);
        final TextView tvOutput = (TextView) findViewById(R.id.tv);

        btnMakeEvent.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Message msg = handler.obtainMessage();
                msg.what = USER_EVENT;
                msg.obj = etInput.getText().toString();
                handler.sendMessage(msg); // Message.obtain(handler, MYEVENT);
            }
        });

        handler = new Handler() {
            public void handleMessage(Message msg) {
                switch(msg.what) {
                    case USER_EVENT:
                        tvOutput.setText((String)msg.obj);
                        break;
                }
            }
        };
    }
}