getting undefined selected value from dropdown in react native

Question

I am new to learn react native. I want to get selected value from dropdown in react-native.

my constructor

constructor(props){
      super(props);
      this.state = ({       
        PickerSelectedVal : ''
      })
}

in render

render(){
      <Dropdown                 
                label="Select"
                options={["Op1","Op2"]}                     
                selectedValue={this.state.PickerSelectedVal}
                onSelect={(obj)=>this.changedemo({obj})}
      />
}

in function

 changedemo= (ob)=>{
      this.setState({PickerSelectedVal : ob});
      alert("Selected country is : " +ob.PickerSelectedVal);
      console.log(this.state.PickerSelectedVal);
      if (this.state.PickerSelectedVal === 1) {
          alert("Selected value is : " +ob.PickerSelectedVal);
      } 
      if(this.state.PickerSelectedVal === 0) {
alert("Selected value is : " +ob.PickerSelectedVal);
      }

  }

I have tried many times. I want to get selected value from dropdown alert is also showing but it prints. Selected value is:undefined.

Pramod · Accepted Answer · 2020-03-17 12:02:03Z

1

setState is a async process so when you are printing it by that time the state is not yet set. Add This

this.setState({PickerSelectedVal : ob},()=>{console.log(this.state.PickerSelectedVal)});

answered Mar 17, 2020 at 12:02

Pramod

1,96810 silver badges15 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Best Sports Over a year ago

thank you! I can show in console. but in alert not showing value. it shows undefined.

Karishma Kavankar · Accepted Answer · 2020-03-17 13:11:45Z

0

your changedemo function must be like following;

  changedemo= (ob)=>{
      this.setState({PickerSelectedVal : ob.value});
      alert("Selected country is : " +ob.value);
      console.log(ob.value);
      // rest of the code
  }

edited Mar 17, 2020 at 13:11

answered Mar 17, 2020 at 12:16

Karishma Kavankar

1002 silver badges12 bronze badges

18 Comments

Best Sports Over a year ago

thanks for reply! alert("Selected country is : " +this.state.PickerSelectedVal); but it shows only Selected Country is : blank value not print any value.

Karishma Kavankar Over a year ago

on first line of changedemo function start add following line alert(ob); and comment here output.

Karishma Kavankar Over a year ago

which package you are using for dropdown?

Best Sports Over a year ago

I have added alert(ob); it show output : [object Object]. I can show object in log also output: { obj: { index: '0', value: 'Op1' } }

Karishma Kavankar Over a year ago

ok so now try this alert("Selected country is : " +ob.value);

|

Collectives™ on Stack Overflow

getting undefined selected value from dropdown in react native

2 Answers 2

1 Comment

18 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

18 Comments

Your Answer

Sign up or log in

Post as a guest

Related