CODEWITHSUNDEEP
angulartypescript
onner
onner

Reputation: 133

How to access class variables in this situation?

I'm using bluetooh serial from ionic native.I want to access a variable defined in class when i'm read somenthing from serial. I set the value for variable but when i want to display it from inside of read function shows me undefined(at alert(this.test)).What can i do ? Here is my code:

import { Component } from '@angular/core';

    import {NavController, Platform} from 'ionic-angular';
    import {BluetoothSerial} from "ionic-native/dist/es5/index";

    @Component({
      selector: 'functions',
      templateUrl: 'functions.html'
    })
    export class Functions {
      public data:any;
      monStart:Boolean;
      devices:any;
      connected:Boolean;
      onConnect:Boolean;
      public test:any;


      constructor(public navCtrl: NavController,platform:Platform) {
    this.test="aaaa";
        platform.ready().then(() => {

        });
      }

      readDataFromSerial() {
        BluetoothSerial.write("g").then((response)=> {
            setTimeout(function () {
              alert("write");
              BluetoothSerial.read().then((response)=> {
                alert(this.test);   
                alert(response);
              })
            }, 1000)
          })
      }

      showListOfDevices() {
        BluetoothSerial.list().then((response)=>{
          alert("Devices:"+JSON.stringify(response));
          this.devices=response;
        })
      }


    }

Upvotes: 0

Views: 783

Answers (2)

Diullei
Diullei

Reputation: 12414

You are using the this.test inside a function declaration: setTimeout(function () { so you just need to change that to an arrow function: setTimeout(() => {

like this:

readDataFromSerial() {
    BluetoothSerial.write("g").then((response)=> {
        setTimeout(() => { // <-- the change goes here
            alert("write");
            BluetoothSerial.read().then((response)=> {
                alert(this.test);   
                alert(response);
            })
        }, 1000)
    })
}

Upvotes: 1

El houcine bougarfaoui
El houcine bougarfaoui

Reputation: 37343

use arrow => function in the setTimeout function :

setTimeout(()=> {
          alert("write");
          BluetoothSerial.read().then((response)=> {
             alert(this.test);   
             alert(response);
          })
    }, 1000)

Upvotes: 4

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