Question

在我的 React Native 应用程序中有一些实例，用户可能会离开应用程序，然后又回来。在 Expo 中运行时，如果用户离开时间过长，他们将失去与服务器的连接。我该如何预防/纠正这种情况？我们正在使用 Websocket

Answer 1

你可以像这样在使用效果中实现addEventListener。

import {AppState} from 'react-native';

useEffect(() => {
  setTimeout(() => {
    AppState.addEventListener("change", _handleAppStateChange);
   }, 2000);
return () => {
  AppState.removeEventListener("change", _handleAppStateChange);
};
}, []);

在这里定义你的 _handleAppStateChange

const _handleAppStateChange = (nextAppState) => {
if (
  appState.current.match(/inactive|background/) &&
  nextAppState === "active"
) {
  console.log("App has come to the foreground!");
  //clearInterval when your app has come back to the foreground
  BackgroundTimer.clearInterval(interval)
  
}else{
  //app goes to background
  console.log('app goes to background')
  //tell the server that your app is still online when your app detect that it goes to background
  interval = BackgroundTimer.setInterval(()=>{
  },100)
appState.current = nextAppState;
console.log("AppState", appState.current);
}

}

如何防止 React Native 中的连接丢失？

1 个答案: