feat: concurrency with schedulers demo (running long operation in bg)

Kaushik Gopal · Kaushik Gopal · commit 081983cf6b81 · 2014-07-23T15:18:14.000-07:00
diff --git a/app/src/main/java/com/morihacky/android/rxjava/ConcurrencyWithSchedulersDemoFragment.java b/app/src/main/java/com/morihacky/android/rxjava/ConcurrencyWithSchedulersDemoFragment.java
@@ -10,36 +10,48 @@
 import android.view.View;
 import android.view.ViewGroup;
 import android.widget.ArrayAdapter;
-import android.widget.Button;
 import android.widget.ListView;
 import android.widget.ProgressBar;
 
 import com.morihacky.android.rxjava.app.R;
 
 import java.util.ArrayList;
 import java.util.List;
-import java.util.concurrent.TimeUnit;
 
 import butterknife.ButterKnife;
 import butterknife.InjectView;
 import butterknife.OnClick;
 import rx.Observable;
 import rx.Observer;
 import rx.Subscriber;
+import rx.Subscription;
+import rx.android.observables.AndroidObservable;
+import rx.android.schedulers.AndroidSchedulers;
 import rx.schedulers.Schedulers;
 import timber.log.Timber;
 
 public class ConcurrencyWithSchedulersDemoFragment
     extends Fragment {
 
 
-//    @InjectView(R.id.btn_start_operation) Button _btnStart;
     @InjectView(R.id.progress_operation_running) ProgressBar _progress;
     @InjectView(R.id.list_threading_log) ListView _logsList;
 
     private LogAdapter _adapter;
     private List<String> _logs;
+    private Subscription _subscription;
 
+    @OnClick(R.id.btn_start_operation)
+    public void startLongOperation() {
+
+        _progress.setVisibility(View.VISIBLE);
+        _log("Button Clicked");
+
+        _subscription = AndroidObservable.bindFragment(this, _getObservable())      // Observable
+                            .subscribeOn(Schedulers.io())
+                            .observeOn(AndroidSchedulers.mainThread())
+                            .subscribe(_getObserver());                             // Observer
+    }
 
     // -----------------------------------------------------------------------------------
     // Main Rx entities
@@ -52,15 +64,20 @@ public class ConcurrencyWithSchedulersDemoFragment
      *
      * https://github.com/Netflix/RxJava/wiki/Subject#behaviorsubject
      */
-    private Observable<List<Integer>> _getObservable() {
-        return Observable.create(new Observable.OnSubscribe<Integer>() {
+    private Observable<Boolean> _getObservable() {
+        return Observable.create(new Observable.OnSubscribe<Boolean>() {
 
 
             @Override
-            public void call(Subscriber<? super Integer> observer) {
-                observer.onNext(1);
+            public void call(Subscriber<? super Boolean> observer) {
+
+                _log("Within Observable");
+
+                _doSomeLongOperation_thatBlocksCurrentThread();
+                observer.onNext(true);
+                observer.onCompleted();
             }
-        }).buffer(2, TimeUnit.SECONDS);
+        });
     }
 
     /**
@@ -71,43 +88,78 @@ public void call(Subscriber<? super Integer> observer) {
      * 2. onError
      * 3. onNext
      */
-    private Observer<List<Integer>> _getObserver() {
-        return new Observer<List<Integer>>() {
+    private Observer<Boolean> _getObserver() {
+        return new Observer<Boolean>() {
 
 
             @Override
             public void onCompleted() {
-                _mainThreadHandler.post(new Runnable() {
-
-
-                    @Override
-                    public void run() {
-                        _addLogToAdapter(String.format("%d taps", _counter));
-                        _counter = 0;
-                    }
-                });
+                _log("On complete");
+                _progress.setVisibility(View.INVISIBLE);
             }
 
             @Override
             public void onError(Throwable e) {
-                Timber.e(e, "--------- Woops on error!");
+                Timber.e(e, "Error in RxJava Demo concurrency");
+                _log(String.format("Boo Error %s", e.getMessage()));
+                _progress.setVisibility(View.INVISIBLE);
             }
 
             @Override
-            public void onNext(List<Integer> integers) {
-                for (int i : integers) {
-                    _counter += i;
-                }
-
-                Timber.d("--------- on next with a count of %d", _counter);
-                onCompleted();
+            public void onNext(Boolean aBoolean) {
+                _log(String.format("onNext with return value \"%b\"", aBoolean));
             }
         };
     }
 
+    @Override
+    public void onDestroy() {
+        super.onDestroy();
+        _subscription.unsubscribe();
+    }
+
+    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);
+                }
+            });
+        }
+    }
+
     // -----------------------------------------------------------------------------------
     // Method that help wiring up the example (irrelevant to RxJava)
 
+    private void _doSomeLongOperation_thatBlocksCurrentThread() {
+        _log("performing long operation");
+
+        try {
+            Thread.sleep(3000);
+        } catch (InterruptedException e) {
+            e.printStackTrace();
+        }
+    }
+
+    @Override
+    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
+        super.onActivityCreated(savedInstanceState);
+        _setupLogAdapter();
+    }
+
     @Override
     public View onCreateView(LayoutInflater inflater,
                              @Nullable ViewGroup container,
@@ -120,13 +172,11 @@ public View onCreateView(LayoutInflater inflater,
     private void _setupLogAdapter() {
         _logs = new ArrayList<String>();
         _adapter = new LogAdapter(getActivity(), new ArrayList<String>());
-        _logsListView.setAdapter(_adapter);
+        _logsList.setAdapter(_adapter);
     }
 
-    private void _addLogToAdapter(String logMsg) {
-        _logs.add(0, logMsg);
-        _adapter.clear();
-        _adapter.addAll(_logs);
+    private boolean _isCurrentlyOnMainThread() {
+        return Looper.myLooper() == Looper.getMainLooper();
     }
 
     private class LogAdapter
diff --git a/app/src/main/res/layout/fragment_concurrency_schedulers.xml b/app/src/main/res/layout/fragment_concurrency_schedulers.xml
@@ -24,11 +24,11 @@
             android:layout_width="wrap_content"
             android:layout_marginLeft="20dp"
             android:textSize="16sp"
-            android:text="Start long running operation"/>
+            android:text="Start long operation"/>
 
         <ProgressBar
             android:id="@+id/progress_operation_running"
-            android:visibility="gone"
+            android:visibility="invisible"
             android:layout_height="wrap_content"
             android:layout_width="wrap_content"
             android:layout_marginLeft="20dp"/>
