CODEWITHSUNDEEP
javascriptreact-native
Muhammad Lebda
Muhammad Lebda

Reputation: 33

react native: _this2.setState is not a function

I have function that works when a button is clicked. The function was working well before I add the setInterval method, after I added it, it shows the error : _this2.setState is not a function

here's the function :

 getWifiNetworksOnPress() {
   setInterval(function timer() {
   console.log("hello world");
   wifi.loadWifiList(
     wifiStringList => {
       console.log(wifiStringList);
       var wifiArray = JSON.parse(wifiStringList);
       this.setState({
         wifiList: wifiArray
       });
     },
     error => {
       console.log(error);
     }
   );
  }, 3000);
}

and here's the button : 

<Button onPress={this.getWifiNetworksOnPress.bind(this)}>
  get location
</Button>

all the answers I found for this problem was adding .bind(this) to the onPress, but it didn't work. any idea how to solve this problem ?

Upvotes: 0

Views: 155

Answers (2)

Nandu Kkd
Nandu Kkd

Reputation: 392

Why don't you use a fat-arrow function inside the setInterval function? This should work:

getWifiNetworksOnPress = () => {
    setInterval(() => {
        console.log("hello world");
        wifi.loadWifiList(wifiStringList => {
            console.log(wifiStringList);
            var wifiArray = JSON.parse(wifiStringList);
            this.setState({
                wifiList: wifiArray
            });
        }, error => {
            console.log(error);
        });
    }, 3000);
}

And

<Button onPress={this.getWifiNetworksOnPress}>
    Search Networks
</Button>

Upvotes: 1

diogenesgg
diogenesgg

Reputation: 2859

Try adding a reference to the class using a const _this like the following code:

getWifiNetworksOnPress() {
   const this_ = this;
   setInterval(function timer() {
     console.log("hello world");
     wifi.loadWifiList(
       wifiStringList => {
         console.log(wifiStringList);
         var wifiArray = JSON.parse(wifiStringList);
         this_.setState({
           wifiList: wifiArray
         });
       },
       error => {
         console.log(error);
       }
     );
  }, 3000);
}

Upvotes: 0

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