simple rxjava code programming style

package zhangphil.rx;

import android.os.SystemClock;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.TextView;

import java.util.concurrent.Callable;

import io.reactivex.Observable;
import io.reactivex.android.schedulers.AndroidSchedulers;
import io.reactivex.observers.DisposableObserver;
import io.reactivex.schedulers.Schedulers;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        final TextView text = findViewById(R.id.text);

        DisposableObserver mDisposableObserver = new DisposableObserver<String>() {
            @Override
            public void onNext(String s) {
                text.setText(s);
            }

            @Override
            public void onComplete() {

            }

            @Override
            public void onError(Throwable e) {

            }
        };

        Observable.fromCallable(new Callable<String>() {
            @Override
            public String call() throws Exception {
                SystemClock.sleep(10000);

                return "zhang phil";
            }
        }).subscribeOn(Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe(mDisposableObserver);
    }
}

in app's gradle,need ref:

    compile 'io.reactivex.rxjava2:rxandroid:2.0.1'
    compile 'io.reactivex.rxjava2:rxjava:2.1.8'