Question

我是Android新手，致力于近场通信，用于从NFC标签读取数据。我既没有NFC支持的Android手机也没有NFC标签来测试我创建的应用程序。

我发现以下两篇文章说的是通过触发意图伪造NFC标签扫描。

Possibility for Fake NFC(Near Field Communication) Launch
Need To Fake an NFC Tag Being Scanned In Android

我根据第一篇文章更改了我的代码，点击按钮我在第一个活动中触发了所需的Intent。虽然我已经创建了一个能够处理相同意图的活动。 NFC标签和处理数据的读取基于第二个活动的按钮点击。

问题是：每当我从第一个活动触发假的NFC标签扫描意图时，它就会抛出一个错误＆＃34; 没有找到活动来处理Intent {act = android.nfc.action.NDEF_DISCOVERED （有额外的）} ＆＃34;。

Manifest文件是这样的：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.expensemanager.saubhattacharya">

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

<uses-feature android:name="android.hardware.nfc" android:required="false" />

<application
    android:allowBackup="true"
    android:icon="@mipmap/icon1"
    android:label="@string/app_name"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    <activity
        android:name=".MainActivity"
        android:label="@string/app_name"
        android:theme="@style/AppTheme.NoActionBar">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity
        android:name=".Set_Monthly_Target"
        android:label="@string/title_activity_set__monthly__target"
        android:parentActivityName=".MainActivity">
        <meta-data
            android:name="android.support.PARENT_ACTIVITY"
            android:value="com.expensemanager.saubhattacharya.MainActivity" />
        <intent-filter>
            <action android:name="android.nfc.action.NDEF_DISCOVERED" />
            <category android:name="android.intent.category.DEFAULT" />
            <data android:mimeType="text/plain"/>
            <data android:mimeType="image/*" />
        </intent-filter>
    </activity>
    <activity
        android:name=".Add_Daily_Expense"
        android:label="@string/add_daily_expense_activity"
        android:parentActivityName=".MainActivity">
        <meta-data
            android:name="android.support.PARENT_ACTIVITY"
            android:value="com.expensemanager.saubhattacharya.MainActivity" />
        <intent-filter>
            <action android:name="android.nfc.action.NDEF_DISCOVERED" />
            <category android:name="android.intent.category.DEFAULT" />
            <data android:mimeType="text/plain"/>
            <data android:mimeType="image/*" />
        </intent-filter>
    </activity>
</application>

</manifest>

第一项活动的意图触发器代码段如下：

public void scan_tag (View view)
{
    final Intent intent = new Intent(NfcAdapter.ACTION_NDEF_DISCOVERED);
    intent.putExtra(NfcAdapter.EXTRA_NDEF_MESSAGES, "Custom Messages");
    startActivity(intent);
}

处理上述触发器的第二个活动的代码片段如下：

public class Add_Daily_Expense extends AppCompatActivity {

Button read_data;
TextView show_data;
Tag detected_tag;
NfcAdapter nfcAdapter;
IntentFilter[] intentFilters;
public static final String MIME_TEXT_PLAIN = "text/plain";
public static final String MIME_IMAGE_ALL = "image/*";

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_add__daily__expense);
    final PackageManager pm = this.getPackageManager();
    show_data = (TextView) findViewById(R.id.show_data);
    nfcAdapter = NfcAdapter.getDefaultAdapter(getApplicationContext());
    read_data = (Button) findViewById(R.id.read_nfc);
    read_data.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if (!pm.hasSystemFeature(PackageManager.FEATURE_NFC)) {
                try {
                    AlertDialog.Builder builder = new AlertDialog.Builder(Add_Daily_Expense.this);
                    builder.setMessage("NFC feature is not available on this device!")
                            .setCancelable(false)
                            .setPositiveButton("OK", new DialogInterface.OnClickListener() {
                                public void onClick(DialogInterface dialog, int id) {
                                    dialog.cancel();
                                }
                            });
                    AlertDialog alert = builder.create();
                    alert.show();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            } else {
                Toast.makeText(getApplicationContext(), "NFC feature is available on this device!", Toast.LENGTH_SHORT).show();
                HandleIntent(getIntent());
            }
        }
    });
}

public void HandleIntent(Intent intent)
{
    String action = intent.getAction();
    if(NfcAdapter.ACTION_NDEF_DISCOVERED.equals(action))
    {
        detected_tag = getIntent().getParcelableExtra(nfcAdapter.EXTRA_TAG);
        NDefReaderTask NDefReader = new NDefReaderTask();
        NDefReader.execute();
    }
}

public void onResume()
{
    super.onResume();
    if(nfcAdapter != null)
    setupForeGroundDispatch(this, nfcAdapter);
}

public void onPause()
{
    super.onPause();
    if(nfcAdapter != null)
    stopForeGroundDispatch(this, nfcAdapter);
}

public void onNewIntent(Intent intent)
{
    HandleIntent(intent);
}

public void setupForeGroundDispatch (final Activity activity, NfcAdapter nfcAdapter)
{
    Intent new_intent = new Intent(getApplicationContext(),Add_Daily_Expense.class);
    new_intent.setFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);

    PendingIntent pendingIntent = PendingIntent.getActivity(getApplicationContext(),0,new_intent,0);
    intentFilters = new IntentFilter[1];
    String[][] techList = new String[][]{};

    intentFilters[0] = new IntentFilter();
    intentFilters[0].addAction(NfcAdapter.ACTION_NDEF_DISCOVERED);
    intentFilters[0].addCategory(Intent.CATEGORY_DEFAULT);
    try {
        intentFilters[0].addDataType(MIME_TEXT_PLAIN);
        intentFilters[0].addDataType(MIME_IMAGE_ALL);
    }
    catch(IntentFilter.MalformedMimeTypeException me)
    {
        me.printStackTrace();
    }

    nfcAdapter.enableForegroundDispatch(activity, pendingIntent, intentFilters, techList);
}

public void stopForeGroundDispatch (final Activity activity, NfcAdapter nfcAdapter)
{
    nfcAdapter.disableForegroundDispatch(activity);
}

public class NDefReaderTask extends AsyncTask <Tag, Void, String>
{
    @Override
    protected String doInBackground(Tag... params)
    {
        try
        {
            detected_tag = params[0];
            Ndef ndef = Ndef.get(detected_tag);
            ndef.connect();
            if(ndef != null)
            {
                NdefMessage ndefMessage = ndef.getCachedNdefMessage();
                NdefRecord[] records = ndefMessage.getRecords();
                for(NdefRecord ndefRecord : records)
                {
                    if((ndefRecord.getTnf() == NdefRecord.TNF_ABSOLUTE_URI) || (ndefRecord.getTnf() == NdefRecord.TNF_WELL_KNOWN))
                    {
                        byte[] payload = ndefRecord.getPayload();
                        String encoding1 = "UTF-8";
                        String encoding2 = "UTF-16";
                        String textEncoding = ((payload[0] & 128) == 0) ? encoding1 : encoding2;
                        int languageCodeLength = payload[0] & 0063;
                        return new String(payload, languageCodeLength + 1, payload.length - languageCodeLength - 1, textEncoding);
                    }
                }
            }
            ndef.close();
        }
        catch (UnsupportedEncodingException UE)
        {
            UE.printStackTrace();
        }
        catch (IOException IE)
        {
            IE.printStackTrace();
        }
        return null;
    }

    @Override
    protected void onPreExecute()
    {

    }

    protected void onPostExecute(String result)
    {
        if(result != null)
        {
            show_data.setText(result);
        }
    }
}
}

我的问题是：我在这里做错了什么？有没有其他方法通过伪造NFC标签扫描来测试我的应用程序？

Answer 1

您为NDEF_DISCOVERED意图过滤器指定MIME类型过滤器：

<data android:mimeType="text/plain"/>
<data android:mimeType="image/*" />

因此，伪NFC意图需要包含这些MIME类型中的一种以匹配意图过滤器。您可以使用setType()方法将类型信息添加到intent：

public void scan_tag (View view) {
    final Intent intent = new Intent(NfcAdapter.ACTION_NDEF_DISCOVERED);
    intent.setType("text/plain");
    intent.putExtra(NfcAdapter.EXTRA_NDEF_MESSAGES, ...);
    startActivity(intent);
}

另请注意，上述代码不会为NFC意图添加标记句柄。因此，您无法使用

获取Tag个对象

detected_tag = getIntent().getParcelableExtra(nfcAdapter.EXTRA_TAG);

因此，您也无法使用

获取Ndef连接类的实例

Ndef ndef = Ndef.get(detected_tag);

您可能希望查看以下有关模拟标记对象的问题/答案：

最后，请注意您的代码中还有其他一些问题。

通过伪造NFC标签扫描来测试应用程序

1 个答案: