reactjs - React Native, Warning: setState(...): Can only update a mounted or mounting component -

here's index.ios.js constructor:

i want make dynamic

  constructor(props){     super(props);     this.state = {       testmessage : ''     }     this.testf()   }    testf(){     this.setstate({testmessage:'asdasd'});     console.log(this.state)       } 

here's error:

warning: setstate(...): can update mounted or mounting component. means called setstate() on unmounted component. no-op.

how can solve it?

that's because using setstate inside constructor. state regular object. using setstte value updated , component re-rendered. when call setstate in constructor, component not mounted yet, got warning. can use componentwillmount or componentdidmount using setstate. or change state this.state in constructor.