没有或没有网络连接时，应用程序会崩溃 [英] flutter app crash when there is low or no network connection

问题描述

我有这个IconButton，当我按下它时会更新我的Cloud Firestore DB上的一个字段。如果互联网连接正常，没有网络或信号不足，我都不会超时错误，这会导致应用崩溃。我已经将函数包装在try {} catch {}块中，但仍然无济于事。

I have this IconButton which when I press it updates a field on my cloud Firestore DB.I do not get any problem if there is a healthy internet connection, how ever is there is no network or low signal I get a timed out error and this causes the app to crash. I have have wraped the function in a try{} catch{} block but still that doesn't help.

 onPressed: (){
                 try{
                  Firestore.instance.runTransaction((Transaction thistransaction)async{
                  DocumentSnapshot docSnapshot = await thistransaction
                  .get(snapshotDocuments[index].reference);
                  await thistransaction.update(docSnapshot.reference,
                   {'voteUpBool':!docSnapshot['voteUpBool']});

                  });
                }
                 catch(err){
                    print(err.toString());
                  }
                 },

推荐答案

您必须检查Internet或wifi是否可用，只需添加最新版本的 connectivity：^ 0.3.1 依赖项并遵循以下代码即可。

you have to check internet or wifi available or not for that just add connectivity: ^0.3.1 dependency with latest version and follow the below code.

import 'dart:io';
...
try {
   final result = await InternetAddress.lookup('google.com');
   if (result.isNotEmpty && result[0].rawAddress.isNotEmpty) {
       print('connected');
   }
 } on SocketException catch (_) {
    print('not connected');
 }

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