this.translate.get(friendlyErrorMessageKey).subscribe((message:string) => {
			let nav:NavController = this.app.getActiveNav();
			let toast:Toast = Toast.create({
				message: message,
				duration: message.length * 100 + 2000
			});
			nav.present(toast);
		});

	addLesson() {
		this.nav.push(LessonFormPage).then(() => {
			// dismissing before the nav.push breaks the "back" button in the next view.
			// https://github.com/driftyco/ionic/issues/6820
			this.viewCtrl.dismiss();
		});
	}

  openActionSheet() {
    let actionSheet = ActionSheet.create({
      title: '选择操作',
      buttons: [
        {
          text: '立即播放',
          handler: () => {
            audio.src = 'http://www.yaoshining.com/file/musicyao?key=Isaac%20Shepard-Felicity.mp3';
            audio.play();
            let modal = Modal.create(PlayerPage);
            this.nav.present(modal);
          }
        },
        {
          text: '添加至下一首'
        },
        {
          text: '添加至队列末'
        },
        {
          text: '替换队列'
        },
        {
          text: '更多…'
        }
      ]
    });

    this.nav.present(actionSheet);
  }

 public showAlert(title:string, message:string) {
     let alert = Alert.create({
         title: title,
         subTitle: message,
         buttons: ['OK']
     });
     this._nav.present(alert);
 }

        this.events.listen(_EXT_NOTIFICATION_EVENTS.call_requested,this.userNotificationChannel,data=>{
            console.log('call need to be answered data',data[0].message.callData);
            let callData=data[0].message.callData;
            callData.callToMake=false;
            let modal=Modal.create(AnswerCallPage,{callData:callData});
            this.navController.present(modal);

        });

    rejectWithMessage(){
        let popover = Popover.create(RejectCallPopover);
        popover.onDismiss(data=>{
            if(!data.message)return;
            this.callData['note']=data.message;
            this.reject();
            console.log('data from popover',data);
        });
        this.navController.present(popover);

    }

    submit() {
        this.newPost.timestamp = new Date().getTime();

        let loading = Loading.create({
            content: "Submitting ..."
        });
        this.navCtrl.present(loading);

        //when post done, destroy loading and dismiss current view
        let posts = this.backend.posts({}); //adding {} as parameter to get the .push which is not there if we
                                            // supply the defualt query for some reason
        posts.push(this.newPost).then(res=>{
            loading.destroy();
            this.viewCtrl.dismiss();
        });

        //todo handle offline case #6 https://github.com/pascalwhoop/esn-couchsurfing/issues/6

    }

 openProjectListPage() {
   this.analytics.trackEvent("Discover Page", "project list");
   this.nav.push(ProjectListPage);
 }

 openTodoListsPage() {
   this.analytics.trackEvent("Discover Page", "todo list");
   this.nav.push(TodoListsPage);
 }

 openToolboxListPage() {
   this.analytics.trackEvent("Discover Page", "toolbox");
   this.nav.push(ToolboxListPage);
 }