当第一个选择为“DISCOVERER”而另一个选择为“CONNECTOR”时，我在这里编写的代码似乎连接了两个设备。
当我尝试执行“SEND PACKAGE”时，它说 Payload 已发送，但另一台设备完全没有执行任何操作。
对于这个项目，我使用
https://pub.dev/packages/nearby_connections (3.1.0)
https://pub.dev/packages/permission_handler (8.3.0)
点对点策略，在这个情况下，是 P2P_CLUSTER。（可以在这里找到不同的策略
https://developers.google.com/nearby/connections/strategies）
idFriend 在开始时为 0。稍后它将在每个设备上将其覆盖为每个设备上的 EndPointId。
作为连接器的设备的用户名
是 2。作为发现者的设备的用户名是 1。
另外，我在下面添加了代码，例如 acceptpackage() 和 sendpack()。sendpack() 似乎有效，而 acceptpackage() 实际上并不接受它，特别是因为 acceptpackage() 已经在 connect() 的代码中。
import 'dart:async';
import 'dart:convert';
import 'dart:io';
import 'dart:math';
import 'dart:typed_data';
import 'package:flutter/material.dart';
import 'package:nearby_connections/nearby_connections.dart';
import 'package:permission_handler/permission_handler.dart';
final String connector_userName = "2";
final String discoverer_userName = "1";
final Strategy strategy = Strategy.P2P_CLUSTER;
class peerwidget extends StatefulWidget {
@override
_peerwidgetState createState() => _peerwidgetState();
}
String mytext = "";
class _peerwidgetState extends State<peerwidget> {
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text("Somecrab", textDirection: TextDirection.ltr),
actions: <Widget>[
IconButton(
icon: const Icon(Icons.settings),
onPressed: () {
print("OPENING SETTINGS FOR BACKGROUND COLOR AND SUCH");
}),
]),
body: SingleChildScrollView(
child: Column(children: <Widget>[
Container(
child: Text(mytext),
),
ElevatedButton(
style: ElevatedButton.styleFrom(
minimumSize: const Size(140, 50),
),
onPressed: () {
print("location");
//setstate oderso, nächsts Bild holle
locationpermission();
},
child: Column(
// Replace with a Row for horizontal icon + text
children: const <Widget>[
Icon(Icons.arrow_forward),
Text("Ask location"),
],
),
),
ElevatedButton(
style: ElevatedButton.styleFrom(
minimumSize: const Size(140, 50),
),
onPressed: () {
print("storage");
//setstate oderso, nächsts Bild holle
storagepermission();
},
child: Column(
// Replace with a Row for horizontal icon + text
children: const <Widget>[
Icon(Icons.arrow_forward),
Text("Ask storage"),
],
),
),
ElevatedButton(
style: ElevatedButton.styleFrom(
minimumSize: const Size(140, 50),
),
onPressed: () {
print("Kill all");
//setstate oderso, nächsts Bild holle
closeall();
},
child: Column(
// Replace with a Row for horizontal icon + text
children: const <Widget>[
Icon(Icons.arrow_forward),
Text("Kill all"),
],
),
),
ElevatedButton(
style: ElevatedButton.styleFrom(
minimumSize: const Size(140, 50),
),
onPressed: () {
print("CONNECT");
//setstate oderso, nächsts Bild holle
setState(() {
connect();
});
},
child: Column(
// Replace with a Row for horizontal icon + text
children: const <Widget>[
Icon(Icons.arrow_forward),
Text("CONNECT"),
],
),
),
ElevatedButton(
style: ElevatedButton.styleFrom(
minimumSize: const Size(140, 50),
),
onPressed: () {
print("DISCOVER");
//setstate oderso, nächsts Bild holle
setState(() {
discover();
});
},
child: Column(
// Replace with a Row for horizontal icon + text
children: const <Widget>[
Icon(Icons.arrow_forward),
Text("DISCOVER"),
],
),
),
ElevatedButton(
style: ElevatedButton.styleFrom(
minimumSize: const Size(140, 50),
),
onPressed: () {
print("SEND PACKAGE");
//setstate oderso, nächsts Bild holle
setState(() {
sendpack();
});
},
child: Column(
// Replace with a Row for horizontal icon + text
children: const <Widget>[
Icon(Icons.arrow_forward),
Text("SEND PACKAGE"),
],
),
),
ElevatedButton(
style: ElevatedButton.styleFrom(
minimumSize: const Size(140, 50),
),
onPressed: () {
print("ACCEPT PACKAGE");
//setstate oderso, nächsts Bild holle
setState(() {
acceptpackage();
});
},
child: Column(
// Replace with a Row for horizontal icon + text
children: const <Widget>[
Icon(Icons.arrow_forward),
Text("ACCEPT PACKAGE"),
],
),
),
]),
),
);
}
}
onConnectionInitiated() {
mytext = "onConnectionInitiated";
}
onConnectionResult() {
mytext = "onConnectionResult";
}
onDisconnected() {
mytext = "onConnectionDisconnected";
}
onEndpointFound(String id, String username, String serviceId) {
mytext = "Found: " + id + username + serviceId;
}
onEndpointLost() {
mytext = "onEndpointLost";
}
bool connectionexists = false;
//var theendpointid = "1";
String idFriend = "0";
connect() async {
print("connecting started...");
mytext = "connection started";
try {
await Nearby().startAdvertising(
connector_userName,
strategy,
onConnectionInitiated: (String id, ConnectionInfo info) {
print("[CONNECTION INITIATED]: \n ID: " +
id +
" info: " +
info.toString());
idFriend = id;
Nearby().acceptConnection(id, onPayLoadRecieved: (endpointId, payload) {
print("[ACCEPT CONNECTION]: \n EndpointID: " +
endpointId +
" Payload: " +
payload.toString());
// called whenever a payload is recieved.
}, onPayloadTransferUpdate: (endpointId, payloadTransferUpdate) {
print("[PAYLOAD TRANSFER UPDATE]: \n endpointId: " +
endpointId +
" PayloadTransferUpdate: " +
payloadTransferUpdate.toString());
// gives status of a payload
// e.g success/failure/in_progress
// bytes transferred and total bytes etc
});
},
onConnectionResult: (String id, Status status) {
print("[CONNECTION RESULT] \n ID: " +
id +
" status: " +
status.toString());
// Called when connection is accepted/rejected
},
onDisconnected: (String id) {
print("[DISCONNECTED] \n ID: " + id);
// Callled whenever a discoverer disconnects from advertiser
onDisconnected();
},
serviceId: "com.simon.fluttershit", // uniquely identifies your app
);
} catch (PlatformException) {
print("exception at 187");
print("insufficient permissions or some error!");
// platform exceptions like unable to start bluetooth or insufficient permissions
}
}
discover() async {
//print("the connection existance is:" + connectionexists.toString());
mytext = "discovery started";
//Does it stay within this loop because await? No.
/*if (connectionexists == false) {*/
try {
await Nearby().startDiscovery(
discoverer_userName,
strategy,
onEndpointFound: (String id, String userName, String serviceId) {
print("[ENDPOINT FOUND]: \n ID: " +
id +
" userName: " +
userName +
" serviceId: " +
serviceId +
"\n");
print("WAS CONNECTED TO: " + discoverer_userName);
try {
Nearby().requestConnection(
userName,
id,
onConnectionInitiated: (id, info) {
print("[CONNECTION INITIATED]: \n ID: " +
id +
" Info: " +
info.toString());
connectionexists = true;
idFriend = id;
},
onConnectionResult: (id, status) {
print("[CONNECTION RESULT]: \n" + id + " " + status.toString());
},
onDisconnected: (id) {
print("[DISCONNECTED]: \n" + id);
connectionexists = false;
},
);
} catch (PlatformException) {
print("exception at 187");
print("insufficient permissions or some error!");
}
},
serviceId: "com.simon.fluttershit",
onEndpointLost: (String? endpointId) {
print("[ENDPOINT LOST]: \n" + endpointId.toString());
}, // uniquely identifies your app
);
} catch (PlatformException) {
print("exception at 187");
print("insufficient permissions or some error!");
// platform exceptions like unable to start bluetooth or insufficient permissions
}
/*} else {
print("please disconnect first!");
}*/
}
void sendpack() {
List<int> data = [102, 111, 114, 116, 121, 45, 116, 119, 111, 0];
Uint8List bytes = Uint8List.fromList(data);
Nearby().sendBytesPayload(idFriend, bytes);
print("[SENDPACK]: Receiver ID: " +
idFriend.toString() +
"Data: " +
bytes.toString());
}
void acceptpackage() {
Nearby().acceptConnection(idFriend, onPayLoadRecieved: (endpointId, payload) {
print("Something was received: EndpointId: " +
endpointId +
" Payload: " +
payload.toString());
// called whenever a payload is recieved.
}, onPayloadTransferUpdate: (endpointId, payloadTransferUpdate) {
print("The status of Payload is: EndPointId: " +
endpointId +
" PayloadTransferUpdate: " +
payloadTransferUpdate.toString());
// gives status of a payload
// e.g success/failure/in_progress
// bytes transferred and total bytes etc
});
}
void locationpermission() {
Nearby().askLocationPermission();
}
void storagepermission() {
Nearby().askExternalStoragePermission();
}
void closeall() {
connectionexists = false;
Nearby().stopAdvertising();
Nearby().stopDiscovery();
Nearby().stopAllEndpoints();
}
发送到发现者的有效负载连接器上的输出：
I/flutter (28055): [CONNECTION INITIATED]:
I/flutter (28055): ID: D0ND info: Instance of 'ConnectionInfo'
I/ViewRootImpl@d507b48[MainActivity](28055): ViewPostIme pointer 0
I/ViewRootImpl@d507b48[MainActivity](28055): ViewPostIme pointer 1
I/flutter (28055): SEND PACKAGE
D/nearby_connections(28055): sentPayload
I/flutter (28055): [SENDPACK]: Receiver ID: D0NDData: [102, 111, 114, 116, 121, 45, 116, 119, 111, 0]
D/nearby_connections(28055): ad.onConnectionResult
发现者向连接器发送有效负载的输出：
I/flutter (28055): connecting started...
D/nearby_connections(28055): startAdvertising
D/nearby_connections(28055): ad.onConnectionInitiated
I/flutter (28055): [CONNECTION INITIATED]:
I/flutter (28055): ID: M9N3 info: Instance of 'ConnectionInfo'
I/ViewRootImpl@d507b48[MainActivity](28055): ViewPostIme pointer 0
I/ViewRootImpl@d507b48[MainActivity](28055): ViewPostIme pointer 1
I/flutter (28055): ACCEPT PACKAGE
E/flutter (28055): [ERROR:flutter/lib/ui/ui_dart_state.cc(209)] Unhandled Exception: PlatformException(Failure, 8009: STATUS_OUT_OF_ORDER_API_CALL, null, null)
E/flutter (28055): #0 StandardMethodCodec.decodeEnvelope (package:flutter/src/services/message_codecs.dart:607:7)
E/flutter (28055): #1 MethodChannel._invokeMethod (package:flutter/src/services/platform_channel.dart:156:18)
E/flutter (28055): <asynchronous suspension>
E/flutter (28055): #2 Nearby.acceptConnection (package:nearby_connections/src/nearby.dart:342:12)
E/flutter (28055): <asynchronous suspension>
E/flutter (28055):
该程序的图片，用于发现者和连接器：
请帮我弄清楚为什么发现者或连接器都没有收到 PayLoad。