SharedPrefenreces の値変更 + RxAndroid で状態の変更をバックグラウンドのActivityに伝える

前回のエントリ「状態の変更をバックグラウンドのActivityに伝える方法はどれがいいんだろう？」の 3) を RxAndroid を使って実装してみました。

onStart() で値をチェックするのではなく、SharedPreferences の値が true になったイベントと起動時の処理を同じストリームになるようにしてみました。

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1. public class MainActivity extends Activity {  
2.   
3.     @InjectView(R.id.list)  
4.     ListView listView;  
5.   
6.     private Subscription subscription = Subscriptions.empty();  
7.   
8.     private static final String FAVORITE_PREF_KEY = "favorite_changed";  
9.   
10.     @Override  
11.     protected void onCreate(Bundle savedInstanceState) {  
12.         super.onCreate(savedInstanceState);  
13.         setContentView(R.layout.activity_main);  
14.         ButterKnife.inject(this);  
15.   
16.         final SharedPreferences pref = getSharedPreferences("reload_flag", MODE_PRIVATE);  
17.   
18.         final Observable<List<String>> observable = ContentObservable.fromSharedPreferencesChanges(pref)  
19.                 .filter(new Func1<String, Boolean>() {  
20.                     @Override  
21.                     public Boolean call(String prefKey) {  
22.                         return FAVORITE_PREF_KEY.equals(prefKey) && pref.getBoolean(prefKey, false);  
23.                     }  
24.                 })  
25.                 .startWith(FAVORITE_PREF_KEY)  
26.                 .flatMap(new Func1<String, Observable<List<String>>>() {  
27.                     @Override  
28.                     public Observable<List<String>> call(String s) {  
29.                         return Observable.create(new Observable.OnSubscribe<List<String>>() {  
30.                             @Override  
31.                             public void call(Subscriber<? super List<String>> subscriber) {  
32.                                 try {  
33.                                     subscriber.onNext(getDataFromServer());  
34.                                 } catch (Exception e) {  
35.                                     subscriber.onError(e);  
36.                                 }  
37.                             }  
38.                         }).subscribeOn(Schedulers.newThread());  
39.                     }  
40.                 });  
41.   
42.         subscription = AppObservable.bindActivity(this, observable)  
43.                 .subscribe(new Subscriber<List<String>>() {  
44.                     @Override  
45.                     public void onCompleted() {  
46.                     }  
47.   
48.                     @Override  
49.                     public void onError(Throwable e) {  
50.                         e.printStackTrace();  
51.                         pref.edit().putBoolean(FAVORITE_PREF_KEY, false).apply();  
52.                     }  
53.   
54.                     @Override  
55.                     public void onNext(List<String> data) {  
56.                         listView.setAdapter(new ArrayAdapter<>(MainActivity.this,  
57.                                 android.R.layout.simple_list_item_1, data));  
58.                         pref.edit().putBoolean(FAVORITE_PREF_KEY, false).apply();  
59.                     }  
60.                 });  
61.     }  
62.   
63.     private List<String> getDataFromServer() throws Exception {  
64.         // mock  
65.         Thread.sleep(1000);  
66.   
67.         final Calendar c = Calendar.getInstance();  
68.   
69.         List<String> data = new ArrayList<>();  
70.         for (int i = 0; i < 20; i++) {  
71.             data.add(i + " : " + DateFormat.format("hh時mm分ss秒", c));  
72.         }  
73.         return data;  
74.     }  
75.   
76.     @Override  
77.     protected void onDestroy() {  
78.         subscription.unsubscribe();  
79.         super.onDestroy();  
80.     }  
81.   
82.     @OnItemClick(R.id.list)  
83.     void onItemClick(int position) {  
84.         Intent intent = new Intent(this, SubActivity.class);  
85.         startActivity(intent);  
86.     }  
87. }  

public class MainActivity extends Activity { @InjectView(R.id.list) ListView listView; private Subscription subscription = Subscriptions.empty(); private static final String FAVORITE_PREF_KEY = "favorite_changed"; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); ButterKnife.inject(this); final SharedPreferences pref = getSharedPreferences("reload_flag", MODE_PRIVATE); final Observable<List<String>> observable = ContentObservable.fromSharedPreferencesChanges(pref) .filter(new Func1<String, Boolean>() { @Override public Boolean call(String prefKey) { return FAVORITE_PREF_KEY.equals(prefKey) && pref.getBoolean(prefKey, false); } }) .startWith(FAVORITE_PREF_KEY) .flatMap(new Func1<String, Observable<List<String>>>() { @Override public Observable<List<String>> call(String s) { return Observable.create(new Observable.OnSubscribe<List<String>>() { @Override public void call(Subscriber<? super List<String>> subscriber) { try { subscriber.onNext(getDataFromServer()); } catch (Exception e) { subscriber.onError(e); } } }).subscribeOn(Schedulers.newThread()); } }); subscription = AppObservable.bindActivity(this, observable) .subscribe(new Subscriber<List<String>>() { @Override public void onCompleted() { } @Override public void onError(Throwable e) { e.printStackTrace(); pref.edit().putBoolean(FAVORITE_PREF_KEY, false).apply(); } @Override public void onNext(List<String> data) { listView.setAdapter(new ArrayAdapter<>(MainActivity.this, android.R.layout.simple_list_item_1, data)); pref.edit().putBoolean(FAVORITE_PREF_KEY, false).apply(); } }); } private List<String> getDataFromServer() throws Exception { // mock Thread.sleep(1000); final Calendar c = Calendar.getInstance(); List<String> data = new ArrayList<>(); for (int i = 0; i < 20; i++) { data.add(i + " : " + DateFormat.format("hh時mm分ss秒", c)); } return data; } @Override protected void onDestroy() { subscription.unsubscribe(); super.onDestroy(); } @OnItemClick(R.id.list) void onItemClick(int position) { Intent intent = new Intent(this, SubActivity.class); startActivity(intent); } }

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1. public class SubActivity extends Activity {  
2.   
3.     @Override  
4.     protected void onCreate(Bundle savedInstanceState) {  
5.         super.onCreate(savedInstanceState);  
6.         setContentView(R.layout.activity_sub);  
7.         ButterKnife.inject(this);  
8.     }  
9.   
10.     @OnClick(R.id.favorite_button)  
11.     void onFavoriteButtonClicked() {  
12.         // サーバー通信とかして、状態を変更できたとする  
13.   
14.         final SharedPreferences pref = getSharedPreferences("reload_flag", MODE_PRIVATE);  
15.         pref.edit().putBoolean("favorite_changed", true).apply();  
16.     }  
17. }  

public class SubActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_sub); ButterKnife.inject(this); } @OnClick(R.id.favorite_button) void onFavoriteButtonClicked() { // サーバー通信とかして、状態を変更できたとする final SharedPreferences pref = getSharedPreferences("reload_flag", MODE_PRIVATE); pref.edit().putBoolean("favorite_changed", true).apply(); } }

SubActivity でボタンをクリックすると、MainActivity でリロードが走ります。