等待的意图总是会产生新的活动

Question

我正在尝试制作具有nfc功能的应用程序。问题是，当nfc标签被发现时，挂起的意图总是会产生一个已经存在的新活动。我用的是tab主机。如何在不进行新活动的情况下制作悬挂帐篷。谢谢。

 public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.main);        

            mNfcAdapter = NfcAdapter.getDefaultAdapter(this);                              
            mNfcPendingIntent = PendingIntent.getActivity(this, 0,new Intent(this,
    getClass()).addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP), 0);
    }

    protected void onResume() {    
            super.onResume();
            mResumed = true;               
            // Sticky notes received from Android
            if (NfcAdapter.ACTION_NDEF_DISCOVERED.equals(getIntent().getAction())) {            
                NdefMessage[] messages = getNdefMessages(getIntent());
                byte[] payload = messages[0].getRecords()[0].getPayload();            
                try     { cekNfc(new String(payload)); }
                catch (SQLException e)          { e.printStackTrace(); } 
                catch (NoSuchAlgorithmException e)      {  e.printStackTrace(); }
                catch (UnsupportedEncodingException e)  { e.printStackTrace(); }

                setIntent(new Intent());
            }
            enableNdefExchangeMode();        
        }   
        private void enableNdefExchangeMode() { mNfcAdapter.enableForegroundDispatch(this, mNfcPendingIntent, mNdefExchangeFilters, null); } 

    NdefMessage[] getNdefMessages(Intent intent) {  // Parse the intent             
            NdefMessage[] msgs = null;        
            String action = intent.getAction();
            //jika ada action
            if (NfcAdapter.ACTION_TAG_DISCOVERED.equals(action) || NfcAdapter.ACTION_NDEF_DISCOVERED.equals(action)) {                      
                Parcelable[] rawMsgs = intent.getParcelableArrayExtra(NfcAdapter.EXTRA_NDEF_MESSAGES);
                if (rawMsgs != null) {
                    msgs = new NdefMessage[rawMsgs.length];
                    for (int i = 0; i < rawMsgs.length; i++) {  msgs[i] = (NdefMessage) rawMsgs[i]; }
                }
            } 
            return msgs;
        }


 public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.main);        

            mNfcAdapter = NfcAdapter.getDefaultAdapter(this);                              
            mNfcPendingIntent = PendingIntent.getActivity(this, 0,new Intent(this,
    getClass()).addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP), 0);
    }

    protected void onResume() {    
            super.onResume();
            mResumed = true;               
            // Sticky notes received from Android
            if (NfcAdapter.ACTION_NDEF_DISCOVERED.equals(getIntent().getAction())) {            
                NdefMessage[] messages = getNdefMessages(getIntent());
                byte[] payload = messages[0].getRecords()[0].getPayload();            
                try     { cekNfc(new String(payload)); }
                catch (SQLException e)          { e.printStackTrace(); } 
                catch (NoSuchAlgorithmException e)      {  e.printStackTrace(); }
                catch (UnsupportedEncodingException e)  { e.printStackTrace(); }

                setIntent(new Intent());
            }
            enableNdefExchangeMode();        
        }   
        private void enableNdefExchangeMode() { mNfcAdapter.enableForegroundDispatch(this, mNfcPendingIntent, mNdefExchangeFilters, null); } 

    NdefMessage[] getNdefMessages(Intent intent) {  // Parse the intent             
            NdefMessage[] msgs = null;        
            String action = intent.getAction();
            //jika ada action
            if (NfcAdapter.ACTION_TAG_DISCOVERED.equals(action) || NfcAdapter.ACTION_NDEF_DISCOVERED.equals(action)) {                      
                Parcelable[] rawMsgs = intent.getParcelableArrayExtra(NfcAdapter.EXTRA_NDEF_MESSAGES);
                if (rawMsgs != null) {
                    msgs = new NdefMessage[rawMsgs.length];
                    for (int i = 0; i < rawMsgs.length; i++) {  msgs[i] = (NdefMessage) rawMsgs[i]; }
                }
            } 
            return msgs;
        }

Answer 1

创建您的待定意图如下：

PendingIntent.getActivity(this, 0,new Intent(this,
    getClass()).addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP
    |Intent.FLAG_ACTIVITY_BROUGHT_TO_FRONT
    |Intent.FLAG_ACTIVITY_REORDER_TO_FRONT), 0);

Answer 2

试试这个：

mNotificationIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_SINGLE_TOP);

在你的清单上：

android:launchMode="singleTask"

Answer 3

将您的活动的android:launchMode=“singleTask”放入清单中。这就是诀窍。每当系统发送NFC意图时，总是会创建一个新的活动。这对于NFC来说是独一无二的。因此，设置android:launchMode=“singleTop”将不起作用，在Pending帐篷中设置标志也将不起作用。

另一个解决方案是使用NfcAdapter。在所有活动中启用ForegroundDispatch（）。这样，你的应用程序就可以直接处理所有NFC意图（通过onNewIntent（））。