第一步监听
AppState.addEventListener('change', this._handleAppStateChange);
第二部：
handleAppStateChange = (currentAppState) => {
if(this.lastAppState === 'background' && currentAppState === 'active') {
//refresh
let baseId = this.props.navigation.state.params.id;
let eid = this.props.navigation.state.params.eid;
this.getSignaturePageWord2ImagesResp(baseId, eid);
}
this.lastAppState = currentAppState;
}
第三部：
componentWillUnmount = ()=>{
// Remove the listener when you are done
AppState.removeEventListener('change', this._handleAppStateChange);
}
