Question

我正在尝试使用Android Studio制作Android Messenger，我正在使用unclouded方法。我键入了一个代码来在网络中广播消息，我得到了一个＆＃34;不兼容的类型＆＃34;错误。

enter image description here

公共类MessengerActivity扩展了Activity {

// Unclouded event loop
private Unclouded unclouded;

// Flag to indicate whether device is connected to the network or not
private boolean isOnline;

// Name that is entered in the splash activity
private String myName;

// Adapter to update the list view with string messages
private ArrayAdapter<String> conversationArrayAdapter;

// List of remote references to other devices in the network
private ArrayList buddyList;
/**
 * ATTENTION: This was auto-generated to implement the App Indexing API.
 * See https://g.co/AppIndexing/AndroidStudio for more information.
 */
private GoogleApiClient client;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_messenger);

    buddyList = new ArrayList<>();
    isOnline = false;

    Intent intent = getIntent();
    myName = intent.getStringExtra("NAME");

    ListView conversationView = (ListView) findViewById(R.id.conversation_view);
    Button sendButton = (Button) findViewById(R.id.send_button);

    conversationArrayAdapter = new ArrayAdapter<String>(this, R.layout.message);
    conversationView.setAdapter(conversationArrayAdapter);
    // Make listView to scroll down automatically
    conversationView.setTranscriptMode(AbsListView.TRANSCRIPT_MODE_ALWAYS_SCROLL);

    // When entering a messenger, clear the field and broadcast the messenger
    sendButton.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View arg0) {
            EditText msgField = (EditText) findViewById(R.id.msg_field);
            String msg = msgField.getText().toString();
            msgField.setText("");
            broadcastMessage(msg);
        }

    });

    // Obtain Unclouded event loop
    unclouded = Unclouded.getInstance();

    // Go online and connected to the network
    com.unclouded.android.Network network = unclouded.goOnline();

    // Monitor the network connection to update the isOnline flag
    network.whenever(new NetworkListener() {


        public void isOnline(InetAddress ip) {
            isOnline = true;
        }


        public void isOffline(InetAddress ip) {
            isOnline = false;
            buddyList.clear();
        }

    });

    // MESSENGER type tag to associate with the messenger service
    TypeTag MESSENGER_TYPETAG = new TypeTag("MESSENGER");

    // New instance of the Messenger class.
    Messenger myMessenger = new Messenger();

    // myMessenger is broadcasted by reference (because Messenger implements UObject)
    // This makes a remote reference to this object to be spread across the network
    unclouded.broadcast(MESSENGER_TYPETAG, myMessenger);

    // Listen for remote reference associated with the MESSENGER_TYPETAG type tag
    unclouded.whenever(MESSENGER_TYPETAG, new ServiceListener<RemoteReference>() {

        String buddyName;

        @Override
        public void isDiscovered(RemoteReference remoteReference) {
            // When discovering a buddy, register the remote reference to its Messenger object
            buddyList.add(remoteReference);
            // Asynchronously ask for his name
            Promise promise = remoteReference.asyncInvoke("getName");
            // Listen for the name to be returned
            promise.when(new PromiseListener<String>() {

                @Override
                public void isResolved(String name) {
                    // When name is returned, store it and print messenger on the screen
                    buddyName = name;
                    printBuddyJoinedMessage(name);
                }
            });
        }

        @Override
        public void isDisconnected(RemoteReference remoteReference) {
            // When disconnected, remove buddy from list
            buddyList.remove(remoteReference);
            // If name is already resolved, print disconnection messenger on the screen
            if (buddyName != null) { // Null in case disconnection occurs before name is resolved
                printBuddyDisconnectedMessage(buddyName);
            }
        }

        @Override
        public void isReconnected(RemoteReference remoteReference) {
            // When reconnecting, check whether name has been resolved before
            if (buddyName == null) {
                // If not, treat like a new connection
                isDiscovered(remoteReference);
            } else {
                // Otherwise, add reference to list and print messenger on the screen
                buddyList.add(remoteReference);
                printBuddyJoinedMessage(buddyName);
            }
        }

    });


    // ATTENTION: This was auto-generated to implement the App Indexing API.
    // See https://g.co/AppIndexing/AndroidStudio for more information.
    client = new GoogleApiClient.Builder(this).addApi(AppIndex.API).build();
}

@Override
public boolean onCreateOptionsMenu(final Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.messenger, menu);
    return true;
}

@Override
// Dynamically change menu depending on network status
public boolean onPrepareOptionsMenu(Menu menu) {
    menu.clear();
    getMenuInflater().inflate(R.menu.messenger, menu);
    MenuItem item = menu.findItem(R.id.action_change_network_status);
    if (isOnline) {
        // If connected to the network, show `go offline' action
        item.setTitle(R.string.action_go_offline);
    } else {
        // If disconnected from the network, show `go online' action
        item.setTitle(R.string.action_go_online);
    }
    return super.onPrepareOptionsMenu(menu);
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
        case R.id.action_change_network_status:
            if (isOnline) {
                // When clicked and network is online, go offline
                unclouded.goOffline();
            } else {
                // When clicked and network is offline, go online
                unclouded.goOnline();
            }
            return true;
        default:
            return super.onOptionsItemSelected(item);
    }
}


// Broadcast a messenger in the network
private void broadcastMessage(String msg) {
    // Loop over all discovered buddies...
    // ... and asynchronously invoke their receiveMsg method;

//这里不需要等待返回值 for（RemoteReference reference：buddyList） reference.asyncInvoke（＆＃34; receiveMsg＆＃34;，myName，msg）; //将messenge打印到屏幕上 printMessage（myName，msg）; }

private void printMessage(final String name, final String msg) {
    addToAdapter(name + ": " + msg);
}


private void printBuddyJoinedMessage(final String name) {
    addToAdapter(name + " has joined the conversation.");
}

private void printBuddyDisconnectedMessage(final String name) {
    addToAdapter(name + " has left the conversation.");
}

// Main method to print something on the screen
private void addToAdapter(final String msg) {
    // Necessary because most invocations are initiated by the Unclouded event loop
    runOnUiThread(new Runnable() {
        public void run() {
            conversationArrayAdapter.add(msg);
        }
    });
}

/**
 * ATTENTION: This was auto-generated to implement the App Indexing API.
 * See https://g.co/AppIndexing/AndroidStudio for more information.
 */
public Action getIndexApiAction() {
    Thing object = new Thing.Builder()
            .setName("Messenger Page") // TODO: Define a title for the content shown.
            // TODO: Make sure this auto-generated URL is correct.
            .setUrl(Uri.parse("http://[ENTER-YOUR-URL-HERE]"))
            .build();
    return new Action.Builder(Action.TYPE_VIEW)
            .setObject(object)
            .setActionStatus(Action.STATUS_TYPE_COMPLETED)
            .build();
}

@Override
public void onStart() {
    super.onStart();

    // ATTENTION: This was auto-generated to implement the App Indexing API.
    // See https://g.co/AppIndexing/AndroidStudio for more information.
    client.connect();
    AppIndex.AppIndexApi.start(client, getIndexApiAction());
}

@Override
public void onStop() {
    super.onStop();

    // ATTENTION: This was auto-generated to implement the App Indexing API.
    // See https://g.co/AppIndexing/AndroidStudio for more information.
    AppIndex.AppIndexApi.end(client, getIndexApiAction());
    client.disconnect();
}


// ------------------------------------------

// Instances of the Messenger class are spread across the network
// and allow other devices to share messages
protected class Messenger implements UObject {

    public String getName() {
        return myName;
    }

    public void receiveMsg(String name, String msg) {
        printMessage(name, msg);
    }

}

}

for (RemoteReference reference : buddyList)

中有错误

说有＆＃34;不兼容的类型＆＃34;。预计：对象发现：RemoteReference

我该如何解决问题？

Answer 1

您已将buddylist声明为ArrayList类型。如果你想这样使用它：

    for (RemoteReference reference : buddyList) { ... }

然后您需要将buddyList声明为：

    List<RemoteReference> buddyList;

另一种方法是：

    for (Object obj : buddyList) {
        RemoteReference reference = (RemoteReference) obj;
        ...
    }

这是Java编程的基本误解/错误，它表明您并不完全了解泛型如何工作。

我强烈建议您在generics上花时间阅读（或重读）Oracle Java Tutorial流。

Java不兼容的错误远程参考引用：buddylist错误

1 个答案: