Develop Reference

Reading Array/Payload on NFC Tag?

I've edited my Manifest code and my Activity code again to reflect appropriate intent filter requirements. However, I'm still getting the same results. I'm unable to read my external record, and I don't know why? When I scan my tags with the NFC Tools app, I can see everything as I would expect. My code produces a NullPointer when it attempts to "read" my array and I have no idea why?
--------------BEGIN MANIFEST--------------------
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.bmt_01">
<uses-permission android:name="android.permission.NFC"/>
<uses-permission android:name="android.permission.SEND_SMS"/>
<uses-permission android:name="android.permission.INTERNET"/>
<uses-sdk android:minSdkVersion="15"/> ///must be changed in build.gradle.
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:supportsRtl="true"
android:theme="#style/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
<intent-filter>
<action android:name="android.nfc.action.NDEF_DISCOVERED" />
<category android:name="android.intent.category.DEFAULT" />
<data
android:scheme="vnd.android.nfc"
android:host="ext"
android:pathPrefix="/com.example.bmt_01:externaltype"
/>
</intent-filter>
</activity>
</application>
</manifest>
--------------END MANIFEST--------------------
--------------BEGIN MAIN ACTIVITY-------------
package com.example.bmt_01;
import android.app.Activity;
import android.app.PendingIntent;
import android.content.Intent;
import android.content.IntentFilter;
import android.net.Uri;
import android.nfc.NdefMessage;
import android.nfc.NdefRecord;
import android.nfc.NfcAdapter;
import android.nfc.Tag;
import android.nfc.tech.Ndef;
import android.nfc.tech.NdefFormatable;
import android.os.Parcelable;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.telephony.SmsManager;
import android.util.Log;
import android.widget.TextView;
import android.widget.Toast;
import java.io.ByteArrayOutputStream;
import java.io.UnsupportedEncodingException;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.Locale;
public class MainActivity extends AppCompatActivity {
String currentPayload = "";
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
#Override
protected void onNewIntent(Intent intent)
{
Parcelable[] rawMsgs = intent.getParcelableArrayExtra(NfcAdapter.EXTRA_NDEF_MESSAGES);
//added the below lines, can delete if they don't work.
NdefRecord payload = ((NdefMessage)rawMsgs[0]).getRecords()[0];
String currentPayload = new String(payload.getPayload());
if (currentPayload.equals("1"))
{
Toast.makeText(this, "NFC Scan1: " + currentPayload, Toast.LENGTH_SHORT).show();
String url = "http://www.google.com";
Intent l = new Intent(Intent.ACTION_VIEW);
l.setData(Uri.parse(url));
startActivity(l);
}
///else
///{
if (currentPayload.equals("2"))
{
Toast.makeText(this, "NFC Scan2: " + currentPayload, Toast.LENGTH_SHORT).show();
String url = "http://www.yahoo.com";
Intent l = new Intent(Intent.ACTION_VIEW);
l.setData(Uri.parse(url));
startActivity(l);
}
///}
}
protected void onResume()
{
super.onResume();
Toast.makeText(this, "NFC Scan3: ", Toast.LENGTH_SHORT).show();
enableForegroundDispatchSystem();
}
#Override
protected void onPause()
{
super.onPause();
disableForegroundDispatchSystem();
}
private void enableForegroundDispatchSystem() {
Toast.makeText(this, "NFC Scan4: ", Toast.LENGTH_SHORT).show();
}
private void disableForegroundDispatchSystem() {
Toast.makeText(this, "NFC Scan5: ", Toast.LENGTH_SHORT).show();
onNewIntent(getIntent());
}
}
--------------END MAIN ACTIVITY---------------
UPDATE*
I should add that my AAR functions correctly. When I have the above app installed on my phone, but do not have it open, my AAR automatically opens and launches the application when I scan my test tag. So, I'm able to "see" the AAR in the array, but NOT the external record.
I'm still unable to read the external record on my tag. Obviously I'm doing something wrong, but I have no idea.

You mix togerthe message and record in your for loop. However there is only one NDEF message, but this message can hold several records. You must use only rawMsgs[0]. Then your for loop can iterate over all records of that message.

I've created a library which lets you parse NDEF records.
You're on the right track - wrapping binary paylod with using the external type - the library supports plugging in your own external type parser/record type(s), if you so prefer.

java.net.UnknownHostException: Unable to resolve host "api.openweathermap.org": No address associated with hostname

Please help debug the following code
I have made sure that
1.My Device has Internet access.
2.My Android Manifest file has internet permission.
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.TextView;
import android.widget.Toast;
import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.JsonObjectRequest;
import com.android.volley.toolbox.Volley;
import org.json.JSONException;
import org.json.JSONObject;
public class MainActivity extends AppCompatActivity {
private StringBuilder stringBuilder = null;
private RequestQueue requestQueue;
private String url = "http://api.openweathermap.org/data/2.5/weather?q=London,uk&appid=48b076c80a0b064d62117d19015db014";
private TextView textView;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textView = (TextView) findViewById(R.id.temp);
JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(Request.Method.GET, url, null,
new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
try {
JSONObject jsonObject = response.getJSONObject("main");
float tempr = (float) jsonObject.getDouble("temp");
stringBuilder.append(tempr);
textView.setText(stringBuilder.toString());
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Toast.makeText(getApplicationContext(), error.getMessage().toString(), Toast.LENGTH_LONG).show();
Log.v("Not working", error.getMessage().toString());
}
});
requestQueue = Volley.newRequestQueue(this);
requestQueue.add(jsonObjectRequest);
}
}
The logcat shows the following report:
java.net.UnknownHostException: Unable to resolve host
"api.openweathermap.org": No address associated with hostname
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="androidhive.com.volley5">
<uses-permission android:name="android.permission.INTERNET"/>
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
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>
</application>
</manifest>

Faced the same issue when I was working with openweathermap API.
There are a few steps that solved my issue.
First of all, turn on emulators wifi and mobile data both.
Second, reset permission in androidmenifest.xml file. Add internet permission and also add read and write external storage.
Then run the app. Hope it will solve your error as it solved mine.

Hello.
Today I faced this problem.
There was simply no internet on the phone.
I was helped by checking the connection to Wi-Fi

Can't receive data from URL in android

I have a problem with connecting to internet. I want to show tbe first line in the source code of www.google.com. I coded in Java console and it run well. But when I did it in android, the textView can't not show any words.
Original Java console program:
import java.io.BufferedInputStream;
import java.io.InputStream;
import java.net.URL;
import java.net.URLConnection;
import java.util.Scanner;
public class ReadUrl {
static public String getRespond(String request) {
try{
URL url=new URL (request);
URLConnection connection=url.openConnection();
InputStream in=new BufferedInputStream(connection.getInputStream());
Scanner scanner =new Scanner(in);
String response=scanner.nextLine();
scanner.close();
return response;
}
catch (Exception e){
return null;
}
}
public static void main(String args[]){
System.out.println (getRespond("http://www.google.com"));
}
}
In android:
File MainActivity.java:
package com.example.simpleinternet;
import java.io.BufferedInputStream;
import java.io.InputStream;
import java.net.URL;
import java.net.URLConnection;
import java.util.Scanner;
import android.app.Activity;
import android.app.ActionBar;
import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import android.os.Build;
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
TextView txtView=(TextView) findViewById(R.id.textView);
txtView.setText(getRespond("www.google.com"));
}
public String getRespond(String request) {
try{
URL url=new URL (request);
URLConnection connection=url.openConnection();
InputStream in=new BufferedInputStream(connection.getInputStream());
Scanner scanner =new Scanner(in);
String response=scanner.nextLine();
scanner.close();
return response;
}
catch (IOException e){
return null;
}
}
}
File AndroidManifest.xml:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.simpleinternet"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="16"
android:targetSdkVersion="19" />
<uses-permission android:name="android.permission.INTERNET"/>
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name="com.example.simpleinternet.MainActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
File activity_main.xml:
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="#+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Hello World" />
</FrameLayout>
The error is :
> 07-07 14:44:55.760: E/AndroidRuntime(4449):
> Java.lang.RuntimeException: Unable to start activity
> ComponentInfo{com.example.simpleinternet/com.example.simpleinternet.MainActivity}:
> android.os.NetworkOnMainThreadException
Sorry because I am a newbie in StackOverFlow. I will take it carefully. Can you check it for me ?

android.os.NetworkOnMainThreadException is thrown when an application attempts to perform a networking operation on its main thread.
You can run your code in AsyncTask to solve the issue.

The exception that is thrown when an application attempts to perform a networking operation on its main thread.
Please refer to below links:
What is the problem:
http://developer.android.com/reference/android/os/NetworkOnMainThreadException.html
Why is the problem:
and
Solution:
http://developer.android.com/training/articles/perf-anr.html
How to fix android.os.NetworkOnMainThreadException?

to get cdma dbm on android device

I had tried this one to show my evdo dbm.
it could run on my emulator but couldnt on my real device, why?
is there somethinh wrong ?
this my source code :
package com.cdbmsof2;
import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.telephony.PhoneStateListener;
import android.telephony.SignalStrength;
import android.telephony.TelephonyManager;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
public class CdBmSOF2MainActivity extends Activity implements OnClickListener {
TextView dateAndTimeLabel;
private Button closeButton;
private int signalDBM = 0;
public class GetParams extends PhoneStateListener
{
#Override
public void onSignalStrengthsChanged(SignalStrength signalStrength)
{
super.onSignalStrengthsChanged(signalStrength);
signalDBM = signalStrength.getEvdoDbm();
}
}
#Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
setContentView(R.layout.activity_cd_bm_sof2_main);
GetParams listener = new GetParams();
TelephonyManager TelManager = ( TelephonyManager )getSystemService(Context.TELEPHONY_SERVICE);
TelManager.listen(listener ,PhoneStateListener.LISTEN_SIGNAL_STRENGTHS);
Button btn=(Button)findViewById(R.id.start);
btn.setOnClickListener(this);
}
public void onClick(View v) {
switch (v.getId()) {
case R.id.start:
Toast.makeText(this, "CDMA signal strength is " + this.signalDBM , Toast.LENGTH_SHORT).show();
break;
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_cd_bm_sof2_main, menu);
return true;
}
}
this my manifest.xml :
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.cdbmsof2"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="15" />
<application
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name=".CdBmSOF2MainActivity"
android:label="#string/title_activity_cd_bm_sof2_main" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
<uses-permission android:name="android.permission.CHANGE_NETWORK_STATE" />
</manifest>
any one would help me please? best regards.

You may want to change the MODIFY permission into a READ permission as you're not modifying phone state, but trying to read it:
<uses-permission android:name="android.permission.READ_PHONE_STATE" />

I tried your code but the value of the signalDBM will not change. It will stay the same even if there is no internet connection at all. I am trying to do something similar and your code was of good help for me but now I face that problem. Does that program changes the values for you? Please let me know..

Android project problem

here
I uploaded my Android project made in Eclipse. The idea is that i have a service, which computes the sum of two random numbers. But when i press the OK Button, i don't see the result in that edit box... why? What i'm doing wrong? Please help
Thanks!
EDIT: The code:
//service class
package service;
import java.util.Random;
import com.android.AplicatieSuma;
import android.widget.EditText;
import android.widget.TextView;
public class ServiciuSuma
{
public ServiciuSuma() { }
public int CalculateSum()
{
Random generator=new Random();
int n=generator.nextInt();
int m=generator.nextInt();
return n+m;
}
}
The Application class:
package com.android;
import android.app.*;
import service.*;
public class ApplicationSum extends Application {
public ServiciuSuma service = new ServiciuSuma();
}
and the main Activity class:
package com.android;
import com.android.R;
import android.app.Activity;
import android.content.Intent;
import android.graphics.Color;
import android.graphics.PorterDuffColorFilter;
import android.graphics.drawable.Drawable;
import android.graphics.PorterDuff;
import android.os.Bundle;
import android.provider.Settings;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.EditText;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
public class Activitate extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
View btn_ok = findViewById(R.id.btn_ok);
btn_ok.setOnClickListener(new OnClickListener()
{
public void onClick(View v)
{
CalculeazaSuma();
}
});
}
private void CalculeazaSuma()
{
AplicatieSuma appState = ((AplicatieSuma)this.getApplication());
EditText txt_amount = (EditText)findViewById(R.id.txt_amount);
txt_amount.setText(appState.service.CalculateSum());
//BindData();
}
}
So that edit text does not show the sum of the random generated numbers, by the service. What's wrong?
Thanks
EDIT:
the manifest xml file:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.android"
android:versionCode="1"
android:versionName="1.0.1">
<supports-screens
android:largeScreens="true"
android:normalScreens="true"
android:smallScreens="true"
android:anyDensity="true" />
<application android:name="ApplicationSum" android:icon="#drawable/icon" android:label="#string/app_name" android:debuggable="true">
<activity android:label="#string/app_name" android:name=".Activitate">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
<uses-sdk android:minSdkVersion="7" android:targetSdkVersion="7" />
</manifest>

This fix will work:
txt_amount.setText(String.valueOf(appState.service.CalculateSum()));
Without that you pass integer and android thinks it's an id of a resource to display. You should really use DDMS to identify such problems.

Have you specified in manifest that you want ApplicationSum to be used as application class?
<manifest xmlns:android="http://schemas.android.com/apk/res/android">
<application
android:name="com.android.ApplicationSum">
...
</application>
</manifest>

Does this work?
public String CalculateSum()
{
Random generator=new Random();
int n=generator.nextInt();
int m=generator.nextInt();
String sum = Integer.toString(n+m) ;
Log.v("CalculateSum", "N+M = " + sum);
return sum;
}