NFC中未执行的Newintent方法(意图)

Question

我正在在Android项目中实现NFC。我已经写了AndroidManifest.xml和Java代码中所需的条目。

当任何标签靠近设备时，我的应用程序都会检测标签，然后打开活动，但在这里我获得了NFC标签信息，但onNewIntent不执行。

请分享您的观点。

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);
            }
        }
        finish();
    }
    @Override
    protected void onNewIntent(Intent intent) {
        Tag mTag = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
    }
    @Override
    protected void onPause() {
        super.onPause();
        mNFCAdapter.disableForegroundDispatch(this);
    }
    @Override
    public void onResume() {
        super.onResume();
        mNFCAdapter.enableForegroundDispatch(this, mNfcPendingIntent, null,
                null);
    }
}

androidmanifest.xml

<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>

Answer 1

当活动在前景时，您的代码正常工作，但是当活动以android.nfc.action.XXX_DISCOVERED操作的意图启动时，它将无法正常工作。由于它是第一个意图，因此onNewIntent()不会被调用，但是您可以在onCreate()方法中使用意图。您应该从onCreate()和onNewIntent()调用NFC逻辑，在访问标签之前验证操作。

public class NFCActivity extends Activity {
    private NfcAdapter mNFCAdapter;
    private PendingIntent mNfcPendingIntent;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        ...
        performTagOperations(getIntent());
    }
    @Override
    protected void onNewIntent(Intent intent) {
        performTagOperations(intent);
    }
    private void performTagOperations(Intent intent){
        String action = intent.getAction();
        if(action.equals(NfcAdapter.ACTION_TAG_DISCOVERED) ||
        action.equals(NfcAdapter.ACTION_TECH_DISCOVERED) ){
            //PERFORM TAG OPERATIONS
        }
    }
    ...
}

Answer 2

在我的情况下，我遵循nfcAdapter.enableForegroundDispatch(...) 盲目的文档，然后将此代码粘贴到fragment 中：

pendingIntent = PendingIntent.getActivity(
            this,
            0,
            new Intent(this, getClass())
                .addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP), 0);

由于它实际上期望活动，只需将所有内容更改为getContext()，尤其是getClass()。

pendingIntent = PendingIntent.getActivity(
            getContext(),
            0,
            new Intent(getContext(), getContext().getClass())
                .addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP), 0);