In react native class component , cant not use setstate to update state

Question

I am using this.setState to update state in my component, but something wrong with this, the callback of this.setState is also not executed. here is my code:

{
            this.state.monthData.map((item, index) => (
              <TouchableOpacity onPress={() => this.openMessage(item, index)}
                                style={[styles.calendarItem,
                                  this.state.activeIndex === index ? {
                                    borderWidth: 1,
                                    borderColor: 'red',
                                  } : {}]}
              >
                <Text style={styles.dayTitle}>{item.cDay}</Text>
                <Text style={styles.dayLunar}>{item.Term ?? item.IDayCn}</Text>
                <View style={styles.underline}/>
              </TouchableOpacity>
            ))

          }

constructor (props) {
    super(props)
    this.state = {
      monthData: [],
      offsetMargin: 0,
      activeIndex: null,
    }
  }
openMessage = (item, index) => {
    console.log('index', index) // output correctly
    this.setState({
     activeIndex: index
    }, function (){
      console.log('set success') // here is not executed
    })

what wrong with this?

Answer 1

Try using this way

openMessage = (item, index) => {
  console.log('index', index) // output correctly
  this.setState({
    activeIndex: index
  }, () => {
      console.log('set success') // here is not executed
});