Android Beam - 如何发送正确的数据？

Question

我现在在一个 android beam 项目中。我从 android 开发者那里复制了一个测试类。

我的问题是发送正确的数据。如果我将（p2p）与另一台设备连接并按“Tab to beam”，则只会到达 android 市场的 URI。 但是如果我打开我的浏览器，连接并标签，浏览器的当前网址就会到达。

如何告诉 android 应该发送哪个视图或文本？我没明白。我只想发送一个简单的字符串“你好！”例如

这是代码：

package peer.to.peer;

import java.nio.charset.Charset;
import android.app.Activity;
import android.nfc.NdefMessage;
import android.nfc.NdefRecord;
import android.nfc.NfcAdapter;
import android.nfc.NfcAdapter.CreateNdefMessageCallback;
import android.nfc.NfcAdapter.OnNdefPushCompleteCallback;
import android.nfc.NfcEvent;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;


public class Peer2peerActivity extends Activity implements     
CreateNdefMessageCallback,     OnNdefPushCompleteCallback {
   private Button sendButton;
   private EditText textfield;
   NfcAdapter mNfcAdapter;
   private static final int MESSAGE_SENT = 1;


   /** Called when the activity is first created. */
   @Override
   public void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.main);

          //initialisierung
          sendButton=(Button) findViewById(R.id.button);
          textfield= (EditText) findViewById(R.id.textfield);

          //mNfcAdapter = NfcAdapter.getDefaultAdapter(this);

          //if(mNfcAdapter==null) toast("NFC ist nicht vorhanden");
          //else toast("NFC ist  vorhandne");


          toast("start");

          sendButton.setOnClickListener(mTagWriter);
   }

   //lokaler OnClickListener für den Button
   private View.OnClickListener mTagWriter = new View.OnClickListener() {
    public void onClick(View arg0) {
        // Write to a tag for as long as the dialog is shown.
        //disableNdefExchangeMode();
        //enableTagWriteMode();

          toast(textfield.getText().toString());
    }
   };
   //notification-methode
   public void toast(String text){
          Toast.makeText(this, text, Toast.LENGTH_SHORT).show();
   }

   public void onNdefPushComplete(NfcEvent arg0) {
          // A handler is needed to send messages to the activity when this
    // callback occurs, because it happens from a binder thread
    mHandler.obtainMessage(MESSAGE_SENT).sendToTarget();         
   }

   public NdefMessage createNdefMessage(NfcEvent event) {
    String text = (textfield.toString());
    NdefRecord uriRecord = new NdefRecord(
              NdefRecord.TNF_ABSOLUTE_URI ,
              "http://www.google.de".getBytes(Charset.forName("US-ASCII")),
              new byte[0], new byte[0]);
    NdefMessage msg = new NdefMessage(
            new NdefRecord[] { uriRecord
    //createMimeRecord("text/plain", text.getBytes())
     /**
      * The Android Application Record (AAR) is commented out. When a device
      * receives a push with an AAR in it, the application specified in the AAR
      * is guaranteed to run. The AAR overrides the tag dispatch system.
      * You can add it back in to guarantee that this
      * activity starts when receiving a beamed message. For now, this code
      * uses the tag dispatch system.
      */
      //,NdefRecord.createApplicationRecord("com.example.android.beam")
    });
    return msg;

   }

   /**
 * Creates a custom MIME type encapsulated in an NDEF record
 *
 * @param mimeType
 */
public NdefRecord createMimeRecord(String mimeType, byte[] payload) {
    byte[] mimeBytes = mimeType.getBytes(Charset.forName("US-ASCII"));
    NdefRecord mimeRecord = new NdefRecord(
            NdefRecord.TNF_MIME_MEDIA, mimeBytes, new byte[0], payload);
    return mimeRecord;
}

/** This handler receives a message from onNdefPushComplete */
private final Handler mHandler = new Handler() {
    @Override
    public void handleMessage(Message msg) {
        switch (msg.what) {
        case MESSAGE_SENT:
            Toast.makeText(getApplicationContext(), "Message sent!",     Toast.LENGTH_LONG).show();
            break;
        }
    }
};
}

提前致谢

浆果

Answer 1

您正在获取 URI，因为第一条记录是指向 google.de 的 URI 记录。将 uriRecord 替换为对 createMimeRecord() 的调用，您应该会收到将 mime 类型设置为 text/plain 的文本。

Answer 2

您需要更改createNdefMessage 才能发送简单消息。

String text = (textfield.toString());
NdefMessage msg = new NdefMessage(NdefRecord.createMime( "application/com.example.android.beam", text.getBytes()));
return msg;