package com.rxjava2.android.samples.ui.operators; import android.os.Bundle; import android.util.Log; import android.view.View; import android.widget.Button; import android.widget.TextView; import com.rxjava2.android.samples.R; import com.rxjava2.android.samples.utils.AppConstant; import androidx.appcompat.app.AppCompatActivity; import io.reactivex.Observable; import io.reactivex.Observer; import io.reactivex.disposables.Disposable; /** * Created by amitshekhar on 27/08/16. */ public class ConcatExampleActivity extends AppCompatActivity { private static final String TAG = ConcatExampleActivity.class.getSimpleName(); Button btn; TextView textView; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_example); btn = findViewById(R.id.btn); textView = findViewById(R.id.textView); btn.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { doSomeWork(); } }); } /* * Using concat operator to combine Observable : concat maintain * the order of Observable. * It will emit all the 7 values in order * here - first "A1", "A2", "A3", "A4" and then "B1", "B2", "B3" * first all from the first Observable and then * all from the second Observable all in order */ private void doSomeWork() { final String[] aStrings = {"A1", "A2", "A3", "A4"}; final String[] bStrings = {"B1", "B2", "B3"}; final Observable aObservable = Observable.fromArray(aStrings); final Observable bObservable = Observable.fromArray(bStrings); Observable.concat(aObservable, bObservable) .subscribe(getObserver()); } private Observer getObserver() { return new Observer() { @Override public void onSubscribe(Disposable d) { Log.d(TAG, " onSubscribe : " + d.isDisposed()); } @Override public void onNext(String value) { textView.append(" onNext : value : " + value); textView.append(AppConstant.LINE_SEPARATOR); Log.d(TAG, " onNext : value : " + value); } @Override public void onError(Throwable e) { textView.append(" onError : " + e.getMessage()); textView.append(AppConstant.LINE_SEPARATOR); Log.d(TAG, " onError : " + e.getMessage()); } @Override public void onComplete() { textView.append(" onComplete"); textView.append(AppConstant.LINE_SEPARATOR); Log.d(TAG, " onComplete"); } }; } }