如何檢測 Metamask 上的使用者帳戶是否在前端斷開連接

我正在嘗試建構一個 web3 應用程序。在我的前端，我想檢測使用者是否在 Metamask 錢包上更改了他的帳戶或斷開連接，並希望在前端顯示此更改。我該怎麼做？

 const [account, setaccount] = useState('0x0');
 window.ethereum.on('accountsChanged',async (accounts) =>{
   const changedAccounts =await window.ethereum.request({method: 'eth_requestAccounts'});
   setaccount(changedAccounts[0]);
   console.log('changedAccounts')
 })
 useEffect(async () => {
   if(!window.ethereum){
     window.alert('Please consider installing Metamask');
   }else{
     const accounts =await window.ethereum.request({method: 'eth_requestAccounts'});
     setaccount(accounts[0]);
   }
   if(!window.ethereum.isConnected()){
     console.log('Disconnected')
   }else{
     console.log('Connected')
   }
   console.log('useEffect')
 }, [account]);
 

有更多事件需要監聽，涵蓋所有案例。此外，應該將事件訂閱和清理移到 auseEffect中，以防止記憶體洩漏。

這是一個可以幫助您入門的範例…

const [account, setaccount] = useState('0x0');
useEffect(() => {
 if (!window.ethereum) {
   // Nothing to do here... no ethereum provider found
   return;
 }
 const accountWasChanged = (accounts) => {
   setaccount(accounts[0]);
   console.log('accountWasChanged');
 }
 const getAndSetAccount = async () => {
   const changedAccounts = await window.ethereum.request({ method: 'eth_requestAccounts' });
   setaccount(changedAccounts[0]);
   console.log('getAndSetAccount');
 }
 const clearAccount = () => {
   setaccount('0x0');
   console.log('clearAccount');
 };
 window.ethereum.on('accountsChanged', accountWasChanged);
 window.ethereum.on('connect', getAndSetAccount);
 window.ethereum.on('disconnect', clearAccount);
 window.ethereum.request({ method: 'eth_requestAccounts' }).then(accounts => {
   console.log('accounts', accounts);
   // No need to set account here, it will be set by the event listener
 }, error => {
   // Handle any UI for errors here, e.g. network error, rejected request, etc.
   // Set state as needed 
 })
 return () => {
   // Return function of a non-async useEffect will clean up on component leaving screen, or from re-reneder to due dependency change
   window.ethereum.off('accountsChanged', accountWasChanged);
   window.ethereum.off('connect', getAndSetAccount);
   window.ethereum.off('disconnect', clearAccount);
 }
}, [/* empty array to avoid re-request on every render, but if you have state related to a connect button, put here */]);

引用自：https://ethereum.stackexchange.com/questions/120298