15、NFC技术：使用Android Beam技术传输文件

传输文件的API

从Android4.1开始，NfcAdapter类增加了如下两个推送数据的方法。

NfcAdapter.setBeamPushUris

NfcAdapter.setBeamPushUrisCallback

这两个方法的原型如下：

public void setBeamPushUris(Uri[] uris, Activity activity);

public void setBeamPushUrisCallback(CreateBeamUrisCallback callback, Activity activity);

Demo

 

import java.io.FileOutputStream;
import java.io.InputStream;

import android.app.Activity;
import android.app.PendingIntent; 
import android.content.Intent;
import android.net.Uri;
import android.nfc.NfcAdapter;
import android.nfc.NfcAdapter.CreateBeamUrisCallback;
import android.nfc.NfcEvent;
import android.os.Bundle;

 
public class NFCFileActivity extends Activity implements CreateBeamUrisCallback {
    private NfcAdapter mNfcAdapter;
    private PendingIntent mPendingIntent;
    private final String targetFilename = "/sdcard/temp_icon.png";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_nfcfile);
        
        mNfcAdapter = mNfcAdapter.getDefaultAdapter(this);
        mPendingIntent = PendingIntent.getActivity(this, 0, new Intent(this,
                getClass()), 0);

        try {
            InputStream is = getResources().getAssets().open("icon.png");
            FileOutputStream fos = new FileOutputStream(targetFilename);
            byte[] buffer = new byte[10000];
            int n = is.read(buffer);
            fos.write(buffer, 0, n);
            fos.close();
            is.close();
        } catch (Exception e) {

        }
        mNfcAdapter.setBeamPushUrisCallback(this, this);
    }

    @Override
    public Uri[] createBeamUris(NfcEvent event) {
        Uri[] uris = new Uri[1];
        Uri uri = Uri.parse("file://" + targetFilename);
        uris[0] = uri;
        return uris;
    }

}

<uses-permission android:name="android.permission.NFC" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

   

       其实内部是蓝牙在传输,NFC已经不起作用了，可以相隔一定距离，即使NFC中断也没关系，因为是蓝牙在传输。