Android NFC技术（三）——初次开发Android NFC你须知道NdefMessage和NdefRecord

Android NFC技术（三）——初次开发Android NFC你须知道NdefMessage和NdefRecord

NdefMessage

NdefRecord

开发步骤

1.获取Tag对象

Tag tag = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);

2.判断NFC标签的数格式

Ndef ndef = Ndef.get(tag);

3.写入数据

ndef.wrriteNdefMessage(ndefMessage);

ListActivity

package com.lgl.nfcdemo;

import android.content.Intent;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;

import java.util.ArrayList;
import java.util.List;

/**
* 读取手机软件列表
*
* @author LGL
*/
public class ListActivity extends android.app.ListActivity implements
AdapterView.OnItemClickListener {
//返回码
private static final int CODE = 1;
//封装所有软件
private List<String> mPackage = new ArrayList<String>();

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//这里继承了ListActivity显示列表，不需要加载layout

//获取手机上所有的包
PackageManager manager = getPackageManager();
//把他们装起来
List<PackageInfo> packageInfos = manager.getInstalledPackages(PackageManager.GET_ACTIVITIES);
//遍历
for (PackageInfo pi : packageInfos) {
//添加软件名和包名
mPackage.add(pi.applicationInfo.loadLabel(manager) + "\n" + pi.packageName);
}

//官方的适配器
ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, android.R.id.text1, mPackage);
setListAdapter(arrayAdapter);
//设置单击事件
getListView().setOnItemClickListener(this);

}

@Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {

Intent intent = new Intent();
intent.putExtra("package", mPackage.get(i));
setResult(CODE,intent);
finish();
}
}

MainActivity

package com.lgl.nfcdemo;

import android.app.PendingIntent;
import android.content.Intent;
import android.nfc.FormatException;
import android.nfc.NdefMessage;
import android.nfc.NdefRecord;
import android.nfc.NfcAdapter;
import android.nfc.Tag;
import android.nfc.tech.Ndef;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

import com.google.android.gms.common.api.GoogleApiClient;

import java.io.IOException;

/**
* NFC读写
* Created by lgl on 16/3/1.
*/
public class MainActivity extends AppCompatActivity {

private Button btn_list;
//选中的包名
private String mPackNmae;
private NfcAdapter mNfcAdapter;
private PendingIntent mPendingIntent;

private GoogleApiClient client;

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

btn_list = (Button) findViewById(R.id.btn_list);
//初始化NfcAdapter
mNfcAdapter = NfcAdapter.getDefaultAdapter(this);
//初始化PendingIntent
mPendingIntent = PendingIntent.getActivity(this, 0, new Intent(this, getClass()), 0);

//点击跳转
btn_list = (Button) findViewById(R.id.btn_list);
btn_list.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent intent = new Intent(MainActivity.this,ListActivity.class);
startActivityForResult(intent,1);
}
});

}

//当设置android:launchMode="singleTop"时调用
@Override
protected void onNewIntent(Intent intent) {
super.onNewIntent(intent);
//没有选择的话就不执行操作了
if (mPackNmae == null) {
return;
}

//1.获取Tag对象
Tag tag = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
//写入程序
writeNFC(tag);

}

//NFC写入
private void writeNFC(Tag tag) {
//null不执行操作，强调写程序的逻辑性
if (tag == null) {
return;
}

NdefMessage ndefMessage = new NdefMessage(new NdefRecord[]{NdefRecord.createApplicationRecord(mPackNmae)});
//获得写入大小
int size = ndefMessage.toByteArray().length;
//2.判断是否是NDEF标签
try {
Ndef ndef = Ndef.get(tag);
if(ndef != null) {
//说明是NDEF标签,开始连接
ndef.connect();
//判断是否可写
if(!ndef.isWritable()){
Toast.makeText(this, "当前设备不支持写入",Toast.LENGTH_LONG).show();
return;
}
//判断大小
if(ndef.getMaxSize() < size){
Toast.makeText(this, "容量太小了",Toast.LENGTH_LONG).show();
return;
}
//写入
try {
ndef.writeNdefMessage(ndefMessage);
Toast.makeText(this, "写入成功",Toast.LENGTH_LONG).show();
} catch (FormatException e) {
e.printStackTrace();
}

}
} catch (IOException e) {
e.printStackTrace();

}
}

//使当前窗口置顶，权限高于三重过滤
@Override
protected void onResume() {
super.onResume();

if (mNfcAdapter != null) {
//设置当前activity为栈顶
mNfcAdapter.enableForegroundDispatch(this, mPendingIntent, null, null);
}
}

@Override
protected void onPause() {
super.onPause();
//恢复栈
if (mNfcAdapter != null) {
mNfcAdapter.disableForegroundDispatch(this);
}
}

}

layout_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
android:orientation="vertical">

<Button
android:layout_marginTop="15dp"
android:id="@+id/btn_list"
android:layout_width="200dp"
android:layout_height="45dp"
android:text="绑定应用程序"
android:layout_gravity="center_horizontal" />

<TextView
android:gravity="center_horizontal"
android:textSize="14sp"
android:text="你可以将NFC标签靠近手机背部"
android:layout_width="match_parent"
android:layout_height="wrap_content" />

<ImageView
android:layout_weight="1"
android:background="@mipmap/nfc"
android:layout_width="match_parent"
android:layout_height="0dp" />
</LinearLayout>

Demo下载：http://download.csdn.net/detail/qq_26787115/9457135