我做了一些服务,一些观察者需要订阅才能获得一些数据。问题是服务不在构造函数中,因此永远不会创建实例!如何强制或有其他方法来做到这一点?我正在使用IONIC2框架的Event。我可以在构造函数中添加Class,即使我不使用它,但也许有一个最好的解决方案。提前谢谢。
import {Injectable } from "@angular/core";
import {log, PRIORITY_INFO, PRIORITY_ERROR} from "./log";
import { BackgroundGeolocation } from 'ionic-native';
import Timer = NodeJS.Timer;
import {Platform, Events} from "ionic-angular";
@Injectable()
export class BackgroundGeolocationService {
trackerInterval: Timer;
locations: any;
constructor(private platform: Platform, public trace: log, private events: Events) {
this.trace.info('create BackgroundGeolocationService');
if (this.platform.is('android')) {
this.platform.ready().then(() => {
this.trace.info(`platform android ready` );
// BackgroundGeolocation is highly configurable. See platform specific configuration options
let config = {
interval: 1000,
locationTimeout: 100,
desiredAccuracy: 10,
stationaryRadius: 20,
distanceFilter: 30,
debug: true, // enable this hear sounds for background-geolocation life-cycle.
stopOnTerminate: false // enable this to clear background location settings when the app terminates
};
BackgroundGeolocation.configure((location) => {
this.trace.info(`configure ${location.latitude},${location.longitude}`);
this.setCurrentLocation(location);
this.startTrackingInterval();
// IMPORTANT: You must execute the finish method here to inform the native plugin that you're finished,
// and the background-task may be completed. You must do this regardless if your HTTP request is successful or not.
// IF YOU DON'T, ios will CRASH YOUR APP for spending too much time in the background.
//BackgroundGeolocation.finish(); // FOR IOS ONLY
}, (error) => {
this.trace.error(error);
}, config);
// Turn ON the background-geolocation system. The user will be tracked whenever they suspend the app.
BackgroundGeolocation.start();
}).catch(err => {
this.trace.error(err);
});
}
}
startTrackingInterval(): void {
this.trackerInterval = setInterval(() => { this.refreshLocations(); }, 2000);
}
refreshLocations(): void {
BackgroundGeolocation.getLocations().then(locations => {
this.locations = locations;
if (locations.length != 0) {
this.setCurrentLocation(locations[locations.length-1]);
}
}).catch(error => {
this.trace.error(`BackgroundGeolocationService error ${error}`);
});
}
startTracker(): void {
BackgroundGeolocation.deleteAllLocations();
BackgroundGeolocation.start();
}
setCurrentLocation(location: {latitude:string, longitude:string}) {
this.events.publish('BackgroundGeolocationService:setCurrentLocation', location);
}
stopTracking(): void {
clearInterval(this.trackerInterval);
BackgroundGeolocation.getLocations().then(locations => {
this.locations = locations;
if (locations.length != 0) {
this.setCurrentLocation(locations[locations.length-1]);
}
}).catch(error => {
this.trace.error(error);
});
BackgroundGeolocation.stop();
}
}
答案 0 :(得分:0)
您可以通过添加依赖于它的APP_INITIALIZER
提供程序来强制执行它
{ provide: APP_INITIALIZER,
useFactory: (config: BackgroundGeolocationService) => () => Promise.resolve(null),
deps: [BackgroundGeolocationService],
multi: true }