react-native/Libraries/Utilities/BackAndroid.android.js
Martin Konicek 42eb5464fd Release React Native for Android
This is an early release and there are several things that are known
not to work if you're porting your iOS app to Android.

See the Known Issues guide on the website.

We will work with the community to reach platform parity with iOS.
2015-09-14 18:13:39 +01:00

64 lines
1.5 KiB
JavaScript

/**
* Copyright (c) 2015-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*
* Detect hardware back button presses, and programatically invoke the default back button
* functionality to exit the app if there are no listeners or if none of the listeners return true.
*
* @providesModule BackAndroid
*/
'use strict';
var Set = require('Set');
var DeviceEventManager = require('NativeModules').DeviceEventManager;
var RCTDeviceEventEmitter = require('RCTDeviceEventEmitter');
var DEVICE_BACK_EVENT = 'hardwareBackPress';
type BackPressEventName = $Enum<{
backPress: string;
}>;
var _backPressSubscriptions = new Set();
RCTDeviceEventEmitter.addListener(DEVICE_BACK_EVENT, function() {
var invokeDefault = true;
_backPressSubscriptions.forEach((subscription) => {
if (subscription()) {
invokeDefault = false;
}
});
if (invokeDefault) {
BackAndroid.exitApp();
}
});
var BackAndroid = {
exitApp: function() {
DeviceEventManager.invokeDefaultBackPressHandler();
},
addEventListener: function (
eventName: BackPressEventName,
handler: Function
): void {
_backPressSubscriptions.add(handler);
},
removeEventListener: function(
eventName: BackPressEventName,
handler: Function
): void {
_backPressSubscriptions.delete(handler);
},
};
module.exports = BackAndroid;