我写了一个应用程序来读取和写入 NFC 标签上的 ndef 消息。我的应用程序可以在 NDEF 消息中读取和写入两条 NDEF 记录。但是,当我在 NDEF 消息中展示一个只有一个 NDEF 记录的标签时,应用程序就崩溃了。我知道这背后的原因。而且我也知道如何解决它,但要解决它我需要知道如何获取 NDEF 消息中的记录数?
NdefMessage[] msgs = getNdefMessagesFromIntent(intent);
NdefRecord ndefRecord1 = msgs[0].getRecords()[0];
NdefRecord ndefRecord2 = msgs[0].getRecords()[1]; //problem is here
byte[] payload1 = ndefRecord1.getPayload();
byte[] payload2 = ndefRecord2.getPayload();
//Get the text encoding
String textEncoding1 = ((payload1[0] & 0200) == 0) ? "UTF-8" : "UTF-16";
String textEncoding2 = ((payload2[0] & 0200) == 0) ? "UTF-8" : "UTF-16";
//Get the Language Code
int languageCodeLength1 = payload1[0] & 0077;
int languageCodeLength2 = payload2[0] & 0077;
String text1 = null;
String text2 = null;
//Get the Text
try
{
text1 = new String(payload1, languageCodeLength1 + 1, payload1.length - languageCodeLength1 - 1, textEncoding1);
}
catch (UnsupportedEncodingException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
//Get the Text
try
{
text2 = new String(payload2, languageCodeLength2 + 1, payload2.length - languageCodeLength2 - 1, textEncoding2);
}
catch (UnsupportedEncodingException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
String payloadString1 = new String(text1);
String payloadString2 = new String(text2);
record1.setText(payloadString1);
record2.setText(payloadString2);