Question

我刚刚完成了基于NFC的应用程序。在这里，我只是扫描NFC标签并获取NFC的序列号。

但是当NFC标签靠近设备时，它会显示所有可以扫描NFC标签的应用程序列表，我可以通过“始终”或“默认”来设置，但我希望以编程方式进行此操作。

我正在寻找这个，因为它似乎在一些看似不起作用的设备中出错。

设备中的错误：当NFC标签靠近设备时，我有两个设备甚至没有在对话框中显示“始终”或“默认为操作”。

见截图：

Screenshot

<activity
    android:name="net.livepatrols.thepartnerSA.NFCActivity"
    android:theme="@android:style/Theme.NoDisplay" >
    <intent-filter>
        <action android:name="android.nfc.action.TECH_DISCOVERED" />
    </intent-filter>

    <meta-data
        android:name="android.nfc.action.TECH_DISCOVERED"
        android:resource="@xml/nfc_tech_filter" />

    <intent-filter>
        <action android:name="android.nfc.action.TAG_DISCOVERED" />

        <category android:name="android.intent.category.DEFAULT" />
    </intent-filter>
</activity>

NFCActivity.java

public class NFCActivity extends Activity {

    private NfcAdapter mNFCAdapter;
    private PendingIntent mNfcPendingIntent;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_nfc);

        // Create the OpenSqliteHelper object. It always best to create only
        // once instance of this OpenSqliteHelper
        DatabaseManager.init(this);

        mNFCAdapter = NfcAdapter.getDefaultAdapter(this);

        if (mNFCAdapter == null) {
            // Device does not support NFC
            Toast.makeText(this,
                    getString(R.string.device_does_not_support_nfc),
                    Toast.LENGTH_LONG).show();
        } else {
            if (!mNFCAdapter.isEnabled()) {
                // NFC is disabled
                Toast.makeText(this, getString(R.string.enable_nfc),
                        Toast.LENGTH_LONG).show();
            } else {
                mNfcPendingIntent = PendingIntent.getActivity(NFCActivity.this,
                        0, new Intent(NFCActivity.this, NFCActivity.class)
                                .addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP), 0);
            }
        }
    }

    @Override
    protected void onNewIntent(Intent intent) {
        setIntent(intent);
    }

    @Override
    protected void onPause() {
        super.onPause();
        mNFCAdapter.disableForegroundDispatch(this);
    }

    @Override
    public void onResume() {
        super.onResume();
        try {
            mNFCAdapter.enableForegroundDispatch(this, mNfcPendingIntent, null,
                    null);
            Tag mTag = getIntent().getParcelableExtra(NfcAdapter.EXTRA_TAG);

            byte byteId[] = mTag.getId();

            int size = byteId.length;
            // Convert the byte array to integer
            String str = "";
            if (size > 0) {
                for (int i = 0; i < size; i++) {
                    byte myByte = byteId[i];
                    int myInt = (int) (myByte & 0xFF);
                    str += myInt;
                }
            }

            SimpleDateFormat mSimpleDateFormat = new SimpleDateFormat(
                    "yyyyMMddhhmmss");

            SharedPreferences mSharedPreferences = PreferenceManager
                    .getDefaultSharedPreferences(getApplicationContext());
            boolean mRegistrationStatus = mSharedPreferences.getBoolean(
                    "registration_status", false);
            boolean mExpiredStatus = mSharedPreferences.getBoolean(
                    "expire_status", true);

            Editor mEditor = mSharedPreferences.edit();

            if (mRegistrationStatus && !mExpiredStatus) {

                // Tag here started to scan the the NFC tags
                mEditor.putString("message", "Tag Read in");
                mEditor.commit();

                if (Util.isDeviceConnectedWithInternet(this)) {
                    // Upload the NFC details.

                    // Start the service and send the NFC Tag Info in the
                    // intent.
                    Intent serviceIntent = new Intent(this,
                            UploadNFCTagInfoService.class);

                    serviceIntent.putExtra("mNFCSerialNumber", str);
                    serviceIntent.putExtra("mNFCScannedTimeStamp",
                            mSimpleDateFormat.format(new Date()));
                    startService(serviceIntent);

                } else {

                    // Device is not connected with the Internet.
                    // Store the NFC Tag details in the SQLite database.
                    // When device connect with Internet later then
                    // these records will be uploaded on the database server.

                    Toast.makeText(this, getString(R.string.network_message), Toast.LENGTH_LONG).show();

                    mEditor.putString("message", "Tag has been saved in the application database to upload it later if your device is activated");
                    mEditor.commit();

                    NFCIItem mNFCItem = new NFCIItem();
                    mNFCItem.setSerialNumber(str);
                    mNFCItem.setScanTimeStamp(mSimpleDateFormat
                            .format(new Date()));

                    // Insert the record in the database.
                    DatabaseManager.getInstance().addNFCTag(mNFCItem);

                }
            } else if(!mRegistrationStatus) {
                mEditor.putString("message", "Device is not activated to scan NFC Tags");
                mEditor.commit();
            }
            finish();
        } catch (Exception e) {
            finish();
        }
    }
}

Answer 1

我唯一知道如何解决此问题的方法是在您的代码上添加额外的AAR record（特殊NDEF记录）。随后，只有你的应用程序正在启动，没有人再问了。

Answer 2

你做不到。如果应用程序已打开，您可以使用前台调度使您的应用程序成为首选应用程序（您似乎已经在使用它）。您可以做的最好是调整NFC技术过滤器以尽可能匹配标签（技术+ NDEF等）。对于未显示“始终”选项的设备，如果在对话框中双击应用程序会发生什么？

仅从我的特定应用程序启动NFC标签

2 个答案: