[ReactNative] AppState cleanup, remove Subscribable, add in OSS examples

Libraries/AppStateIOS/AppStateIOS.android.js

@@ -0,0 +1,24 @@
+/**
+ * Copyright 2004-present Facebook. All Rights Reserved.
+ *
+ * @providesModule AppStateIOS
+ */
+'use strict';
+
+var warning = require('warning');
+
+class AppStateIOS {
+
+  static addEventListener(type, handler) {
+    warning('Cannot listen to AppStateIOS events on Android.');
+  }
+
+  static removeEventListener(type, handler) {
+    warning('Cannot remove AppStateIOS listener on Android.');
+  }
+
+}
+
+AppStateIOS.currentState = null;
+
+module.exports = AppStateIOS;

Libraries/AppStateIOS/AppStateIOS.ios.js

@@ -0,0 +1,55 @@
+/**
+ * Copyright 2004-present Facebook. All Rights Reserved.
+ *
+ * @providesModule AppStateIOS
+ */
+'use strict';
+
+var NativeModules = require('NativeModules');
+var RCTDeviceEventEmitter = require('RCTDeviceEventEmitter');
+var RKAppState = NativeModules.RKAppState;
+
+var logError = require('logError');
+
+var DEVICE_APPSTATE_EVENT = 'appStateDidChange';
+
+var _appStateHandlers = {};
+
+class AppStateIOS {
+
+  static addEventListener(type, handler) {
+    _appStateHandlers[handler] = RCTDeviceEventEmitter.addListener(
+      DEVICE_APPSTATE_EVENT,
+      (appStateData) => {
+        handler(appStateData.app_state);
+      }
+    );
+  }
+
+  static removeEventListener(type, handler) {
+    if (!_appStateHandlers[handler]) {
+      return;
+    }
+    _appStateHandlers[handler].remove();
+    _appStateHandlers[handler] = null;
+  }
+
+}
+
+AppStateIOS.currentState = null;
+
+RCTDeviceEventEmitter.addListener(
+  DEVICE_APPSTATE_EVENT,
+  (appStateData) => {
+    AppStateIOS.currentState = appStateData.app_state;
+  }
+);
+
+RKAppState.getCurrentAppState(
+  (appStateData) => {
+    AppStateIOS.currentState = appStateData.app_state;
+  },
+  logError
+);
+
+module.exports = AppStateIOS;