关于我在片段和活动中使用onNewIntent方法遇到的不同问题，我已经就SO提出了多个问题。我现在的问题是，无论我做什么，都不会调用Activity中的onNewIntent。具有onNewIntent的Activity包含多个选项卡。我的标签（片段）包含用于书写和阅读NFC标签的代码。
这是活动的代码：
public class MyAppHome extends AppCompatActivity {
protected DrawerLayout mDrawerLayout;
private ActionBarDrawerToggle mtoggle;
NfcAdapter nfcAdapter;
private Toolbar mtoolbar;
private TextView mName;
private SectionsPagerAdapter mSectionsPagerAdapter;
private ViewPager mViewPager;
private NavigationView mNavigationView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.drawer_layout);
mtoolbar = (Toolbar) findViewById(R.id.nav_action);
setSupportActionBar(mtoolbar);
nfcAdapter = NfcAdapter.getDefaultAdapter(this);
mNavigationView= (NavigationView)findViewById(R.id.nav_view);
mDrawerLayout = findViewById(R.id.drawer_layout);
mtoggle = new ActionBarDrawerToggle(this, mDrawerLayout, R.string.open, R.string.close);
mDrawerLayout.addDrawerListener(mtoggle);
mtoggle.syncState();
// Create the adapter that will return a fragment for each of the three
// primary sections of the activity.
mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.container);
mViewPager.setAdapter(mSectionsPagerAdapter);
TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
mViewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
tabLayout.addOnTabSelectedListener(new TabLayout.ViewPagerOnTabSelectedListener(mViewPager));
tabLayout.setupWithViewPager(mViewPager);
tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
@Override
public void onTabSelected(TabLayout.Tab tab) {
switch (tab.getPosition())
{
case 0:
mViewPager.setCurrentItem(0);
mtoolbar.setTitle("Home");
break;
case 1:
mViewPager.setCurrentItem(1);
mtoolbar.setTitle("Writer");
break;
case 2:
mViewPager.setCurrentItem(2);
mtoolbar.setTitle("Reader");
break;
case 3:
mViewPager.setCurrentItem(3);
mtoolbar.setTitle("Others");
break;
case 4:
mViewPager.setCurrentItem(4);
mtoolbar.setTitle("Alarm");
break;
default:
mViewPager.setCurrentItem(tab.getPosition());
mtoolbar.setTitle("My APP");
break;
}
}
@Override
public void onTabUnselected(TabLayout.Tab tab) {
}
@Override
public void onTabReselected(TabLayout.Tab tab) {
}
});
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
getSupportActionBar().setHomeButtonEnabled(true);
NavigationView navigationView = findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem menuItem) {
// set item as selected to persist highlight
menuItem.setChecked(true);
switch (menuItem.getItemId()){
case R.id.nav_home:
mViewPager.setCurrentItem(0);
mDrawerLayout.closeDrawers();
mtoolbar.setTitle("Home");
break;
case R.id.nav_writer:
mViewPager.setCurrentItem(1);
mDrawerLayout.closeDrawers();
mtoolbar.setTitle("Writer");
break;
case R.id.nav_medication:
mViewPager.setCurrentItem(2);
mDrawerLayout.closeDrawers();
mtoolbar.setTitle("Reader");
break;
case R.id.nav_missedPill:
mViewPager.setCurrentItem(3);
mDrawerLayout.closeDrawers();
mtoolbar.setTitle("Others");
break;
case R.id.nav_alarm:
mViewPager.setCurrentItem(4);
mDrawerLayout.closeDrawers();
mtoolbar.setTitle("Alarm");
break;
case R.id.nav_logout:
FirebaseAuth.getInstance().signOut();
finish();
startActivity(new Intent(getApplicationContext(),Login.class));
}
// close drawer when item is tapped
mDrawerLayout.closeDrawers();
return true;
}
});
mDrawerLayout.addDrawerListener(
new DrawerLayout.DrawerListener() {
@Override
public void onDrawerSlide(View drawerView, float slideOffset) {
// Respond when the drawer's position changes
}
@Override
public void onDrawerOpened(View drawerView) {
// Respond when the drawer is opened
}
@Override
public void onDrawerClosed(View drawerView) {
// Respond when the drawer is closed
}
@Override
public void onDrawerStateChanged(int newState) {
// Respond when the drawer motion state changes
}
}
);
initNFC(getIntent());
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_dosis_home, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
if(mtoggle.onOptionsItemSelected(item)){
return true;
}
//noinspection SimplifiableIfStatement
if (item.getItemId()== R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
@Override
public void onResume() {
super.onResume();
IntentFilter tagDetected = new IntentFilter(NfcAdapter.ACTION_TAG_DISCOVERED);
IntentFilter ndefDetected = new IntentFilter(NfcAdapter.ACTION_NDEF_DISCOVERED);
IntentFilter techDetected = new IntentFilter(NfcAdapter.ACTION_TECH_DISCOVERED);
IntentFilter[] nfcIntentFilter = new IntentFilter[]{techDetected,tagDetected,ndefDetected};
PendingIntent pendingIntent = PendingIntent.getActivity(
this, 0, new Intent(this.getApplicationContext(), this.getClass()).addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP), 0);
if(nfcAdapter !=null){
Log.d("W", "nfcadapter is not null");
nfcAdapter.enableForegroundDispatch(this, pendingIntent, nfcIntentFilter, null);
}
}
@Override
public void onPause() {
super.onPause();
if(nfcAdapter !=null){
disableForegroundDispatchSystem();
}
}
public boolean write2NFC(MyNfcMessage m ) {
NdefMessage ndefMessage = createNdefMessage(m.key1, m.key2,m.key3);
writeNdefMessage(tag, ndefMessage);
return true;
}
private void initNFC(Intent intent) {
if (intent.hasExtra(NfcAdapter.EXTRA_TAG)) {
// if (nfcAdapter.ACTION_TAG_DISCOVERED.equals(intent.getAction())) {
//Toast.makeText(getActivity(), "NfcIntent!", Toast.LENGTH_SHORT).show();
tag = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
}
}
protected void onNewIntent(Intent intent) {
System.out.print("I am here in Home");
Log.d("my tag", "I am here now");
initNFC(intent);
Log.d("my tag ", "onNewIntent: something ");
}
private void disableForegroundDispatchSystem() {
nfcAdapter.disableForegroundDispatch(this);
}
private void formatTag(Tag tag, Nde
fMessage ndefMessage) {
try {
NdefFormatable ndefFormatable = NdefFormatable.get(tag);
if (ndefFormatable == null) {
Toast.makeText(this, "Tag is not ndef formatable!", Toast.LENGTH_SHORT).show();
}
else{
ndefFormatable.connect();
ndefFormatable.format(ndefMessage);
ndefFormatable.close();
Toast.makeText(this, "Tag writen!", Toast.LENGTH_SHORT).show();
}
} catch (Exception e) {
Log.e("formatTag", e.getMessage());
}
}
private void writeNdefMessage(Tag tag, NdefMessage ndefMessage) {
try {
if (tag == null) {
Toast.makeText(this, "Tag object cannot be null", Toast.LENGTH_SHORT).show();
return;
}
Ndef ndef = Ndef.get(tag);
if (ndef == null) {
// format tag with the ndef format and writes the message.
formatTag(tag, ndefMessage);
} else {
ndef.connect();
if (!ndef.isWritable()) {
Toast.makeText(this, "Tag is not writable!", Toast.LENGTH_SHORT).show();
ndef.close();
return;
}
ndef.writeNdefMessage(ndefMessage);
ndef.close();
Toast.makeText(this, "Tag writen!", Toast.LENGTH_SHORT).show();
}
} catch (Exception e) {
Log.e("writeNdefMessage", e.getMessage());
}
}
private NdefRecord createTextRecord(String content) {
try {
byte[] language;
language = Locale.getDefault().getLanguage().getBytes("UTF-8");
final byte[] text = content.getBytes("UTF-8");
final int languageSize = la
nguage.length;
final int textLength = text.length;
final ByteArrayOutputStream payload = new ByteArrayOutputStream(1 + languageSize + textLength);
payload.write((byte) (languageSize & 0x1F));
payload.write(language, 0, languageSize);
payload.write(text, 0, textLength);
return new NdefRecord(NdefRecord.TNF_WELL_KNOWN, NdefRecord.RTD_TEXT, new byte[0], payload.toByteArray());
} catch (UnsupportedEncodingException e) {
Log.e("createTextRecord", e.getMessage());
}
return null;
}
private NdefMessage createNdefMessage(String content, String content2, String content3) {
NdefRecord ndefRecord = createTextRecord(content);
NdefRecord ndefRecord2 = createTextRecord(content2);
NdefRecord ndefRecord3 = createTextRecord(content3);
NdefMessage ndefMessage = new NdefMessage(new NdefRecord[]{ndefRecord, ndefRecord2, ndefRecord3});
return ndefMessage;
}
/**
* A {@link FragmentPagerAdapter} that returns a fragment corresponding to
* one of the sections/tabs/pages.
*/
public class SectionsPagerAdapter extends FragmentPagerAdapter {
private List<Fragment> mFragments = new ArrayList<>();
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
mFragments.add(new Home());
mFragments.add(new Writer());
mFragments.add(new Reader());
mFragments.add(new Others());
mFragments.add(new Alarm());
}
@Override
public Fragment getItem(int position) {
return mFragments.get(position);
}
@Override
public int getCount() {
return mFragments.size();
}
/*to set text instead of icons*/
public CharSequence getPageTitle(int position){
return null;
}
}
}
我的AndroidManifest看起来像这样：
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.NFC" />
<uses-permission android:name="android.permission.USE_FINGERPRINT" />
<uses-feature
android:name="android.hardware.fingerprint"
android:required="false" />
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:launchMode="singleTop"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity android:name=".WelcomeActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".FingerPrint"
android:screenOrientation="portrait" />
<activity
android:name=".MyAppHome"
android:screenOrientation="portrait"
android:windowSoftInputMode="adjustPan">
<intent-filter>
<category android:name="android.intent.category.DEFAULT" />
<category android:name="android.intent.category.LAUNCHER" />
<action android:name="android.nfc.action.TAG_DISCOVERED" />
<action android:name="android.nfc.action.NDEF_DISCOVERED" />
<data android:mimeType="text/plain" />
</intent-filter>
<meta-data
android:name="android.nfc.action.TECH_DISCOVERED"
android:resource="@xml/nfc_tech_filter" />
</activity>
<activity
android:name=".Login"
android:screenOrientation="portrait"
android:theme="@style/AppTheme.NoActionBar" />
</application>
Home Fragment（tab）用于将信息写入NFC标签：
public class Home extends Fragment {
NfcAdapter nfcAdapter;
Button writebtn;
Tag tag;
EditText txtName, txtCountry, txtID;
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view,savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, Bundle savedInstanceState) {
View v= inflater.inflate(R.layout.home, container,false);
txtName = (EditText)view.findViewById(R.id.pName);
txtCountry= (EditText)view.findViewById(R.id.pCountry);
txtID= (EditText)view.findViewById(R.id.pID);
writebtn=(Button)view.findViewById(R.id.nfcWriteBtn);
writebtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
MyAppHome homeActivity = (MyAppHome)getActivity();
MyNfcMessage message = new MyNfcMessage(txtName.getText().toString(), txtCountry.getText().toString(), txtID.getText().toString());
homeActivity.write2NFC(message);
}
});
return v;
}
我不明白为什么永远不会调用活动中的onNewIntent（屏幕上没有显示Toast）。它与我的布局有关吗？
更新：通过创建新项目并将旧项目中的所有代码复制到新项目来解决问题。
答案 0 :(得分：-1)
检查一下：
http://www.helloandroid.com/tutorials/communicating-between-running-activities
在manifest.xml中，在活动标签中设置launchmode =“singleTask”