Android Open Source - Android-RxJava Buffer Demo Fragment

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License

The source code is released under:

Apache License

Java Source Code

package com.morihacky.android.rxjava;
/*  ww w . j a v  a 2s  . c o m*/
import android.content.Context;
import android.os.Bundle;
import android.os.Handler;
import android.os.Looper;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import butterknife.ButterKnife;
import butterknife.InjectView;
import com.morihacky.android.rxjava.app.R;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.TimeUnit;
import rx.Observable;
import rx.Observer;
import rx.Subscriber;
import rx.Subscription;
import rx.android.schedulers.AndroidSchedulers;
import rx.schedulers.Schedulers;
import timber.log.Timber;

/**
 * credit to @tomrozb for this implementation:
 * http://stackoverflow.com/questions/24922610/incorrect-understanding-of-buffer-in-rxjava
 *
 * An alternate mechanism of achieving the same result would be to use a {@link rx.subjects.PublishSubject}
 * as demonstrated in the case of {@link com.morihacky.android.rxjava.SubjectDebounceSearchEmitterFragment}
 */
public class BufferDemoFragment
    extends Fragment {

  @InjectView(R.id.list_threading_log) ListView _logsList;
  @InjectView(R.id.btn_start_operation) Button _tapBtn;

  private LogAdapter _adapter;
  private List<String> _logs;
  private int _tapCount = 0;

  private Subscription _subscription;

  @Override
  public void onResume() {
    super.onResume();
    _subscription = _getBufferedObservable().subscribe(_getObserver());
  }

  @Override
  public void onPause() {
    super.onPause();
    _subscription.unsubscribe();
  }

  @Override
  public void onActivityCreated(@Nullable Bundle savedInstanceState) {
    super.onActivityCreated(savedInstanceState);
    _setupLogger();
  }

  @Override
  public View onCreateView(LayoutInflater inflater,
                           @Nullable ViewGroup container,
                           @Nullable Bundle savedInstanceState) {
    View layout = inflater.inflate(R.layout.fragment_buffer, container, false);
    ButterKnife.inject(this, layout);
    return layout;
  }

  // -----------------------------------------------------------------------------------
  // Main Rx entities

  private Observable<List<Integer>> _getBufferedObservable() {

    return Observable.create(new Observable.OnSubscribe<Integer>() {

      @Override
      public void call(Subscriber<? super Integer> subscriber) {
        _tapBtn.setOnClickListener(new View.OnClickListener() {

          @Override
          public void onClick(View v) {
            Timber.d("--------- GOT A TAP");
            _tapCount += 1;
            _log("GOT A TAP");
          }
        });
      }
    })
        .buffer(2, TimeUnit.SECONDS)
        .subscribeOn(Schedulers.io())
        .observeOn(AndroidSchedulers.mainThread());
  }

  private Observer<List<Integer>> _getObserver() {
    return new Observer<List<Integer>>() {

      @Override
      public void onCompleted() {
        if (_tapCount > 0) {
          _log(String.format("%d taps", _tapCount));
          _tapCount = 0;
        }
      }

      @Override
      public void onError(Throwable e) {
        Timber.e(e, "--------- Woops on error!");
        _log(String.format("Dang error. check your logs"));
      }

      @Override
      public void onNext(List<Integer> integers) {
        Timber.d("--------- onNext");
        if (integers.size() > 0) {
          for (int i : integers) {
            _tapCount += i;
          }
        } else {
          Timber.d("--------- No taps received ");
        }
        onCompleted();
      }
    };
  }

  // -----------------------------------------------------------------------------------
  // Methods that help wiring up the example (irrelevant to RxJava)

  private void _setupLogger() {
    _logs = new ArrayList<String>();
    _adapter = new LogAdapter(getActivity(), new ArrayList<String>());
    _logsList.setAdapter(_adapter);
  }

  private void _log(String logMsg) {

    if (_isCurrentlyOnMainThread()) {
      _logs.add(0, logMsg + " (main thread) ");
      _adapter.clear();
      _adapter.addAll(_logs);
    } else {
      _logs.add(0, logMsg + " (NOT main thread) ");

      // You can only do below stuff on main thread.
      new Handler(Looper.getMainLooper()).post(new Runnable() {

        @Override
        public void run() {
          _adapter.clear();
          _adapter.addAll(_logs);
        }
      });
    }
  }

  private boolean _isCurrentlyOnMainThread() {
    return Looper.myLooper() == Looper.getMainLooper();
  }

  private class LogAdapter
      extends ArrayAdapter<String> {

    public LogAdapter(Context context, List<String> logs) {
      super(context, R.layout.item_log, R.id.item_log, logs);
    }
  }
}

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