javascript - React Native Dynamic Checxbox -

i new in react native. have problem when try dynamically checkbox in react native. checkbox cannot checked, data shown. please me, code:

constructor(props) {       super(props);       this.state = {         loaded: false,         datagedung : null,         datasource: new listview.datasource({ rowhaschanged: (row1, row2) => row1 !== row2, }),         books : [],       };       this.fetchdata = this.fetchdata.bind(this);       this.togglecheck = this.togglecheck.bind(this);       this.renderbook = this.renderbook.bind(this);     }