本文介绍了Android的NFC读取标签的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
在我的申请,我有两个选择:编写和读取NFC标签。我在做所谓的WriteNFC另一个活动NFC标签写入过程。我想我的主要活动读取并显示标签数据,当标签进入范围。写作过程中似乎是好。但每当我试图读取标签。它显示什么。
公共类MainActivity延伸活动{公共静态INT ID = 1;
公共静态INT bakiye = 5;
公共静态语境myContext;
公共静态布尔availableForRead = TRUE;
私人按钮myButton的;保护无效的onCreate(捆绑savedInstanceState){
super.onCreate(savedInstanceState);
的setContentView(R.layout.activity_main);
则myButton =(按钮)findViewById(R.id.button1); myButton.setOnClickListener(新View.OnClickListener(){ 公共无效的onClick(查看为arg0){ 意图I =新意图(getApplicationContext(),nfcWrite.class);
startActivity(ⅰ); }
});}@覆盖
保护无效onResume(){
// TODO自动生成方法存根
super.onResume();}@覆盖
保护无效onNewIntent(意向意图){ 的System.out.println(意图检测);
如果(intent.getType()= NULL和放大器;!&安培; intent.getType()等于(应用程序/+ getPackageName())){
//读取包含NFC数据的第一条记录
Parcelable [] = rawMsgs intent.getParcelableArrayExtra(NfcAdapter.EXTRA_NDEF_MESSAGES);
NdefRecord relayRecord =((NdefMessage)rawMsgs [0])getRecords()[0];
字符串nfcData =新的String(relayRecord.getPayload());
的System.out.println(阅读过程完成...); //显示标签上的数据
Toast.makeText(这一点,nfcData,Toast.LENGTH_SHORT).show(); }}
}
这是我的nfcWrite活动:
包com.example.nfchandler;
进口java.io.IOException异常;
进口java.nio.charset.Charset中;进口android.app.Activity;
进口android.app.PendingIntent;
进口android.content.Context;
进口android.content.Intent;
进口android.content.IntentFilter;
进口android.nfc.FormatException;
进口android.nfc.NdefMessage;
进口android.nfc.NdefRecord;
进口android.nfc.NfcAdapter;
进口android.nfc.Tag;
进口android.nfc.TagLostException;
进口android.nfc.tech.Ndef;
进口android.nfc.tech.NdefFormatable;
进口android.os.Bundle;
进口android.widget.Toast;公共类nfcWrite延伸活动{ 私人INT ID = 1;
私人INT余额= 5; @覆盖
保护无效的onCreate(捆绑savedInstanceState){
// TODO自动生成方法存根
super.onCreate(savedInstanceState);
的setContentView(R.layout.nfc_write);
} @覆盖
保护无效onNewIntent(意向意图){
// TODO自动生成方法存根
super.onNewIntent(意向);
标签标签= intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
串nfcMessage = intent.getStringExtra(nfcMessage); 如果(nfcMessage!= NULL){
writeTag(这一点,标签,nfcMessage);
}
} @覆盖
保护无效onResume(){
// TODO自动生成方法存根
super.onResume();
setupIntent();
} 公共无效setupIntent(){
字符串nfcMessage = ID + - +平衡; //当一个NFC标签进入范围内,调用的主要活动这
//处理数据写入标签
NfcAdapter nfcAdapter = NfcAdapter.getDefaultAdapter(本); 意图nfcIntent =新意图(这一点,nfcWrite.class).addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);
nfcIntent.putExtra(nfcMessage,nfcMessage);
PI的PendingIntent = PendingIntent.getActivity(这一点,0,nfcIntent,PendingIntent.FLAG_UPDATE_CURRENT);
IntentFilter的tagDetected =新的IntentFilter(NfcAdapter.ACTION_TAG_DISCOVERED); nfcAdapter.enableForegroundDispatch((活动)这一点,PI,新的IntentFilter [] {} tagDetected,NULL);
} 公共布尔writeTag(上下文的背景下,标签标签,字符串数据){
//记录发起Play商店,如果没有安装的应用程序
NdefRecord AP precord = NdefRecord.createApplicationRecord(context.getPackageName()); //与我们关心的实际数据记录
NdefRecord relayRecord =新NdefRecord(NdefRecord.TNF_MIME_MEDIA,
新的String(应用程序/+ context.getPackageName())。的getBytes(Charset.forName(US-ASCII))
空,data.getBytes()); //既记录完整NDEF消息
NdefMessage消息=新NdefMessage(新NdefRecord [] {relayRecord,AP precord}); 尝试{
//如果标签已经格式化,只写邮件给它
NDEF NDEF = Ndef.get(标签);
如果(NDEF!= NULL){
ndef.connect(); //确保标签是可写的
如果(!ndef.isWritable()){
Toast.makeText(getApplicationContext(),ETIKETyazılabilirdeğil,Toast.LENGTH_SHORT).show();
返回false;
} //检查是否有对消息的标记足够的空间
。INT大小= message.toByteArray()长;
如果(ndef.getMaxSize()<大小){
Toast.makeText(getApplicationContext(),Etikette yeterli阿兰郁慕明...,Toast.LENGTH_SHORT).show();
返回false;
} 尝试{
//将数据写入标签
ndef.writeNdefMessage(消息); Toast.makeText(getApplicationContext(),信息酒店yazmabaşarılı...,Toast.LENGTH_SHORT).show(); 返回true;
}赶上(TagLostException TLE){
返回false;
}赶上(IOException异常IOE){
返回false;
}赶上(FormatException FE){
返回false;
}
//如果标签没有被格式化,与消息格式化
}其他{
NdefFormatable格式= NdefFormatable.get(标签);
如果(格式!= NULL){
尝试{
format.connect();
format.format(消息); 返回true;
}赶上(TagLostException TLE){
返回false;
}赶上(IOException异常IOE){ 返回false;
}赶上(FormatException FE){ 返回false;
}
}其他{ 返回false;
}
}
}赶上(例外五){ } 返回false;
}}
解决方案
继code解决我的问题:
意向意图= getIntent(); NdefMessage []封邮件;
如果(NfcAdapter.ACTION_NDEF_DISCOVERED.equals(getIntent()。的getAction())){
Parcelable [] = rawMsgs intent.getParcelableArrayExtra(NfcAdapter.EXTRA_NDEF_MESSAGES);
NdefRecord relayRecord =((NdefMessage)rawMsgs [0])getRecords()[0];
字符串nfcData =新的String(relayRecord.getPayload());
Toast.makeText(getApplicationContext(),nfcData,Toast.LENGTH_LONG).show();
}
In my application, I got two options : Writing and Reading a NFC tag. I am doing NFC Tag Writing process in another activity called WriteNFC. I want my main activity reads and displays tag data, when the tag comes into range. Writing process seem to be ok. But whenever i try to read the tag. It displays nothing.
public class MainActivity extends Activity {
public static int id = 1;
public static int bakiye = 5;
public static Context myContext;
public static boolean availableForRead = true;
private Button myButton;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
myButton = (Button) findViewById(R.id.button1);
myButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
Intent i = new Intent(getApplicationContext(), nfcWrite.class);
startActivity(i);
}
});
}
@Override
protected void onResume() {
// TODO Auto-generated method stub
super.onResume();
}
@Override
protected void onNewIntent(Intent intent) {
System.out.println("Intent detected");
if (intent.getType() != null && intent.getType().equals("application/" + getPackageName())) {
// Read the first record which contains the NFC data
Parcelable[] rawMsgs = intent.getParcelableArrayExtra(NfcAdapter.EXTRA_NDEF_MESSAGES);
NdefRecord relayRecord = ((NdefMessage) rawMsgs[0]).getRecords()[0];
String nfcData = new String(relayRecord.getPayload());
System.out.println("Reading Process is Complete...");
// Display the data on the tag
Toast.makeText(this, nfcData, Toast.LENGTH_SHORT).show();
}
}
}
And here is my nfcWrite activity:
package com.example.nfchandler;
import java.io.IOException;
import java.nio.charset.Charset;
import android.app.Activity;
import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.nfc.FormatException;
import android.nfc.NdefMessage;
import android.nfc.NdefRecord;
import android.nfc.NfcAdapter;
import android.nfc.Tag;
import android.nfc.TagLostException;
import android.nfc.tech.Ndef;
import android.nfc.tech.NdefFormatable;
import android.os.Bundle;
import android.widget.Toast;
public class nfcWrite extends Activity {
private int id = 1;
private int balance = 5;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.nfc_write);
}
@Override
protected void onNewIntent(Intent intent) {
// TODO Auto-generated method stub
super.onNewIntent(intent);
Tag tag = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
String nfcMessage = intent.getStringExtra("nfcMessage");
if(nfcMessage != null) {
writeTag(this, tag, nfcMessage);
}
}
@Override
protected void onResume() {
// TODO Auto-generated method stub
super.onResume();
setupIntent();
}
public void setupIntent() {
String nfcMessage = id + "-" + balance;
// When an NFC tag comes into range, call the main activity which
// handles writing the data to the tag
NfcAdapter nfcAdapter = NfcAdapter.getDefaultAdapter(this);
Intent nfcIntent = new Intent(this, nfcWrite.class).addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);
nfcIntent.putExtra("nfcMessage", nfcMessage);
PendingIntent pi = PendingIntent.getActivity(this, 0, nfcIntent, PendingIntent.FLAG_UPDATE_CURRENT);
IntentFilter tagDetected = new IntentFilter(NfcAdapter.ACTION_TAG_DISCOVERED);
nfcAdapter.enableForegroundDispatch((Activity) this, pi, new IntentFilter[] { tagDetected }, null);
}
public boolean writeTag(Context context, Tag tag, String data) {
// Record to launch Play Store if app is not installed
NdefRecord appRecord = NdefRecord.createApplicationRecord(context.getPackageName());
// Record with actual data we care about
NdefRecord relayRecord = new NdefRecord(NdefRecord.TNF_MIME_MEDIA,
new String("application/" + context.getPackageName()).getBytes(Charset.forName("US-ASCII")),
null, data.getBytes());
// Complete NDEF message with both records
NdefMessage message = new NdefMessage(new NdefRecord[] { relayRecord, appRecord });
try {
// If the tag is already formatted, just write the message to it
Ndef ndef = Ndef.get(tag);
if (ndef != null) {
ndef.connect();
// Make sure the tag is writable
if (!ndef.isWritable()) {
Toast.makeText(getApplicationContext(), "Etiket yazılabilir değil", Toast.LENGTH_SHORT).show();
return false;
}
// Check if there's enough space on the tag for the message
int size = message.toByteArray().length;
if (ndef.getMaxSize() < size) {
Toast.makeText(getApplicationContext(), "Etikette yeterli alan yok...", Toast.LENGTH_SHORT).show();
return false;
}
try {
// Write the data to the tag
ndef.writeNdefMessage(message);
Toast.makeText(getApplicationContext(), "Bilgileri yazma başarılı...", Toast.LENGTH_SHORT).show();
return true;
} catch (TagLostException tle) {
return false;
} catch (IOException ioe) {
return false;
} catch (FormatException fe) {
return false;
}
// If the tag is not formatted, format it with the message
} else {
NdefFormatable format = NdefFormatable.get(tag);
if (format != null) {
try {
format.connect();
format.format(message);
return true;
} catch (TagLostException tle) {
return false;
} catch (IOException ioe) {
return false;
} catch (FormatException fe) {
return false;
}
} else {
return false;
}
}
} catch (Exception e) {
}
return false;
}
}
解决方案
Following code solved my problem:
Intent intent=getIntent();
NdefMessage[] msgs;
if (NfcAdapter.ACTION_NDEF_DISCOVERED.equals(getIntent().getAction())) {
Parcelable[] rawMsgs = intent.getParcelableArrayExtra(NfcAdapter.EXTRA_NDEF_MESSAGES);
NdefRecord relayRecord = ((NdefMessage)rawMsgs[0]).getRecords()[0];
String nfcData = new String(relayRecord.getPayload());
Toast.makeText(getApplicationContext(),nfcData,Toast.LENGTH_LONG).show();
}
这篇关于Android的NFC读取标签的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!