package info.testing;
import java.io.IOException;
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.select.Elements;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.webkit.WebView;
import android.widget.Toast;
public class SoupActivity extends Activity {
private static final String TAG = "SoupActivity";
private static final String DATA = null;
private String data = null;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
if(savedInstanceState != null)
{
data = savedInstanceState.getString(DATA);
showResults();
}
else
{
parsePage();
}
}
protected void parsePage(){
Document doc = null;
try {
doc = Jsoup.connect("http://www.mydata.html").get();
Toast.makeText(this, R.string.success, Toast.LENGTH_SHORT).show();
} catch (IOException e) {
Toast.makeText(this, R.string.error, Toast.LENGTH_SHORT).show();
}
Elements rows = doc.select("tr[class]");
data = "<table>" + rows.toString() + "</table>";
showResults();
}
protected void showResults(){
WebView web = (WebView)findViewById(R.id.web);
web.loadData(data, "text/html", "utf-8");
}
#Override
public void onSaveInstanceState(Bundle savedInstanceState){
savedInstanceState.putString(DATA, data);
super.onSaveInstanceState(savedInstanceState);
}
#Override
public void onRestoreInstanceState(Bundle savedInstanceState){
if(savedInstanceState != null)
{
data = savedInstanceState.getString(DATA);
}
super.onRestoreInstanceState(savedInstanceState);
}
}
Flash/Flex developer here starting to get in to Android development, I must admit I am loving it so far, but obviously taking a long time to work out why things happen the way they do.
So the problem I have is that my app crashes without an Internet connection - The application (process.testing) has stopped unexpectedly. This only happens when there is no internet connection and works perfectly if there is one. The only part of my code that accesses the Internet is in a try catch block, can anyone see what I'm doing wrong or how I can handle the error when there is no Internet connection available?
You can use this function to see if a connection is available :
/**
* Check the network state
* #param context context of application
* #return true if the phone is connected
*/
public static boolean isConnected(Context context) {
ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo netInfo = cm.getActiveNetworkInfo();
if (netInfo != null && netInfo.isConnected()) {
return true;
}
return false;
}
When you have no internet connection, doc is probably null and you get NullPointerException because you don't check this case:
Document doc = null;
try {
// connect throws an exception, doc still null
doc = Jsoup.connect("http://www.mydata.html").get();
Toast.makeText(this, R.string.success, Toast.LENGTH_SHORT).show();
} catch (IOException e) {
Toast.makeText(this, R.string.error, Toast.LENGTH_SHORT).show();
}
// dereferencing null (doc) throws NullPointerException
Elements rows = doc.select("tr[class]");
Related
I am developing an application in which message to be sent as soon as an internet connection is available. Connectivity Manager does provide the status of WiFi/Mobile connectivity only. I can ping any site to check internet connectivity. This means I need to continuously poll. Is there any way by which activity can be notified of the restoration of connectivity due to bad network coverage or bad Network connectivity (WiFi back-haul)?
Thanks in advance for your help.
I believe that this is something that you will find helpful How to check internet access on Android? InetAddress never times out. The best solution describes a couple of options.
Hopefully this helps!
I once needed such a solution. So I crafted a class that does the trick with the codes from this site. Let's call this class iChessNetwork:
import android.content.*;
import android.net.*;
import android.net.wifi.*;
import android.os.*;
import android.widget.*;
import java.io.*;
import java.net.*;
public class iChessNetwork {
private Context mContext;
protected Watcher mWatcher;
public iChessNetwork(Context context, Watcher watcher) {
mContext = context;
mWatcher = watcher;
init();
}
public interface Watcher {
public void Online();
}
private void init() {
registerOnlineChecker();
}
public void stop() {
unregisterOnlineChecker();
}
/*=========:INTERNET CHECK START ========*/
private BroadcastReceiver mOnlineChecker = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
if (isConnected()) {
//Toast.makeText(mContext,"You are connected!",Toast.LENGTH_LONG).show();
OnlineTester mOnlineTester = new OnlineTester();
mOnlineTester.execute();
}
}
};
private void registerOnlineChecker() {
IntentFilter filter = new IntentFilter();
filter.addAction(WifiManager.NETWORK_STATE_CHANGED_ACTION);
filter.addAction(WifiManager.WIFI_STATE_CHANGED_ACTION);
filter.addAction(ConnectivityManager.CONNECTIVITY_ACTION);
mContext.registerReceiver(mOnlineChecker, filter);
}
private void unregisterOnlineChecker() {
mContext.unregisterReceiver(mOnlineChecker);
}
private boolean isConnected() {
boolean isMobile = false, isWifi = false;
ConnectivityManager cm = (ConnectivityManager)mContext.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo[] infoAvailableNetworks = cm.getAllNetworkInfo();
if (infoAvailableNetworks != null) {
for (NetworkInfo network : infoAvailableNetworks) {
if (network.getType() == ConnectivityManager.TYPE_WIFI) {
if (network.isConnected() && network.isAvailable())
isWifi = true;
}
if (network.getType() == ConnectivityManager.TYPE_MOBILE) {
if (network.isConnected() && network.isAvailable())
isMobile = true;
}
}
}
return isMobile || isWifi;
}
/*========= INTERNET CHECK END ==========*/
private class OnlineTester extends AsyncTask<Void,Void,Boolean> {
public OnlineTester() {
}
#Override
protected Boolean doInBackground(Void[] p1) {
boolean online = false;
try {
HttpURLConnection urlConnection = (HttpURLConnection)
(new URL("http://clients3.google.com/generate_204")
.openConnection());
urlConnection.setRequestProperty("User-Agent", "Android");
urlConnection.setRequestProperty("Connection", "close");
urlConnection.setConnectTimeout(1500);
urlConnection.connect();
if (urlConnection.getResponseCode() == 204 &&
urlConnection.getContentLength() == 0) {
//Log.d("Network Checker", "Successfully connected to internet");
online = true;
}
} catch (IOException e) {
online = false;
}
return online;
}
#Override
protected void onPostExecute(Boolean online) {
// TODO: Implement this method
super.onPostExecute(online);
if(online) {
if(mWatcher != null) {
mWatcher.Online();
}
}
}
}
};
As you may notice, there is an interface in the class. Basically, I want to know if an "active" internet connection is available or not from one of my Activity classes. So I implemented above interface in that Activity as follows:
public class YourActivity extends Activity implements iChessNetwork.Watcher {
private iChessNetwork mNetwork;
#Override
public void Online() {
// It's online now - do your connection
}
By now, we're ready to go. So I let it run from somewhere (usually, in onCreate(), an android app start point) in the Activity class:
mNetwork = new iChessNetwork(this, this);
And I start tracking "active" internet connection from this point and stop tracking when I don't want it (usually, in onBackPressed() and onDestroy() methods of my Activity like this:
if(mNetwork != null) {
mNetwork.stop();
}
Hope this helps you and someone else.
on line 370 i need a way to look for a string of 'f's' in the advertisement data from a TI CC2650. I found this template online but I'm looking for specific advertising data. Please let me know what string array I need to look at to find this.
package net.jmodwyer.beacon.beaconPoC;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.Dialog;
import android.app.DialogFragment;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.IntentSender;
import android.content.SharedPreferences;
import android.location.Location;
import android.os.Bundle;
import android.os.RemoteException;
import android.preference.PreferenceManager;
import android.text.util.Linkify;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ScrollView;
import android.widget.Toast;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GooglePlayServicesClient;
import com.google.android.gms.location.LocationClient;
import net.jmodwyer.ibeacon.ibeaconPoC.R;
import org.altbeacon.beacon.Beacon;
import org.altbeacon.beacon.BeaconConsumer;
import org.altbeacon.beacon.BeaconManager;
import org.altbeacon.beacon.RangeNotifier;
import org.altbeacon.beacon.Region;
import org.altbeacon.beacon.utils.UrlBeaconUrlCompressor;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
/**
* Adapted from original code written by D Young of Radius Networks.
* #author dyoung, jodwyer
*
*/
public class ScanActivity extends Activity implements BeaconConsumer,
GooglePlayServicesClient.ConnectionCallbacks,
GooglePlayServicesClient.OnConnectionFailedListener {
// Constant Declaration
private static final String PREFERENCE_SCANINTERVAL = "scanInterval";
private static final String PREFERENCE_TIMESTAMP = "timestamp";
private static final String PREFERENCE_POWER = "power";
private static final String PREFERENCE_PROXIMITY = "proximity";
private static final String PREFERENCE_RSSI = "rssi";
private static final String PREFERENCE_MAJORMINOR = "majorMinor";
private static final String PREFERENCE_UUID = "uuid";
private static final String PREFERENCE_INDEX = "index";
private static final String PREFERENCE_LOCATION = "location";
private static final String PREFERENCE_REALTIME = "realTimeLog";
private static final String MODE_SCANNING = "Stop Scanning";
private static final String MODE_STOPPED = "Start Scanning";
protected static final String TAG = "ScanActivity";
/*
* Define a request code to send to Google Play services
* This code is returned in Activity.onActivityResult
*/
private final static int
CONNECTION_FAILURE_RESOLUTION_REQUEST = 9000;
private FileHelper fileHelper;
private BeaconManager beaconManager;
private Region region;
private int eventNum = 1;
// This StringBuffer will hold the scan data for any given scan.
private StringBuffer logString;
// Preferences - will actually have a boolean value when loaded.
private Boolean index;
private Boolean location;
private Boolean uuid;
private Boolean majorMinor;
private Boolean rssi;
private Boolean proximity;
private Boolean power;
private Boolean timestamp;
private String scanInterval;
// Added following a feature request from D.Schmid.
private Boolean realTimeLog;
// LocationClient for Google Play Location Services
LocationClient locationClient;
private ScrollView scroller;
private EditText editText;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_scan);
verifyBluetooth();
PreferenceManager.setDefaultValues(this, R.xml.preferences, false);
BeaconScannerApp app = (BeaconScannerApp)this.getApplication();
beaconManager = app.getBeaconManager();
//beaconManager.setForegroundScanPeriod(10);
region = app.getRegion();
beaconManager.bind(this);
locationClient = new LocationClient(this, this, this);
fileHelper = app.getFileHelper();
scroller = (ScrollView)ScanActivity.this.findViewById(R.id.scanScrollView);
editText = (EditText)ScanActivity.this.findViewById(R.id.scanText);
// Initialise scan button.
getScanButton().setText(MODE_STOPPED);
}
#Override
public void onResume() {
super.onResume();
beaconManager.bind(this);
}
#Override
public void onPause() {
super.onPause();
// Uncommenting the following leak prevents a ServiceConnection leak when using the back
// arrow in the Action Bar to come out of the file list screen. Unfortunately it also kills
// background scanning, and as I have no workaround right now I'm settling for the lesser of
// two evils.
// beaconManager.unbind(this);
}
public String getCurrentLocation() {
/** Default "error" value is set for location, will be overwritten with the correct lat and
* long values if we're ble to connect to location services and get a reading.
*/
String location = "Unavailable";
if (locationClient.isConnected()) {
Location currentLocation = locationClient.getLastLocation();
if (currentLocation != null) {
location = Double.toString(currentLocation.getLatitude()) + "," +
Double.toString(currentLocation.getLongitude());
}
}
return location;
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.main_activity_actions, menu);
return super.onCreateOptionsMenu(menu);
}
#Override
public void onBeaconServiceConnect() {}
/**
*
* #param view
*/
public void onScanButtonClicked(View view) {
toggleScanState();
}
// Handle the user selecting "Settings" from the action bar.
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.Settings:
// Show settings
Intent api = new Intent(this, AppPreferenceActivity.class);
startActivityForResult(api, 0);
return true;
case R.id.action_listfiles:
// Launch list files activity
Intent fhi = new Intent(this, FileHandlerActivity.class);
startActivity(fhi);
return true;
default:
return super.onOptionsItemSelected(item);
}
}
/**
* Start and stop scanning, and toggle button label appropriately.
*/
private void toggleScanState() {
Button scanButton = getScanButton();
String currentState = scanButton.getText().toString();
if (currentState.equals(MODE_SCANNING)) {
stopScanning(scanButton);
} else {
startScanning(scanButton);
}
}
/**
* start looking for beacons.
*/
private void startScanning(Button scanButton) {
// Set UI elements to the correct state.
scanButton.setText(MODE_SCANNING);
((EditText)findViewById(R.id.scanText)).setText("");
// Reset event counter
eventNum = 1;
// Get current values for logging preferences
SharedPreferences sharedPrefs = PreferenceManager.getDefaultSharedPreferences(this);
HashMap <String, Object> prefs = new HashMap<String, Object>();
prefs.putAll(sharedPrefs.getAll());
index = (Boolean)prefs.get(PREFERENCE_INDEX);
location = (Boolean)prefs.get(PREFERENCE_LOCATION);
uuid = (Boolean)prefs.get(PREFERENCE_UUID);
majorMinor = (Boolean)prefs.get(PREFERENCE_MAJORMINOR);
rssi = (Boolean)prefs.get(PREFERENCE_RSSI);
proximity = (Boolean)prefs.get(PREFERENCE_PROXIMITY);
power = (Boolean)prefs.get(PREFERENCE_POWER);
timestamp = (Boolean)prefs.get(PREFERENCE_TIMESTAMP);
scanInterval = (String)prefs.get(PREFERENCE_SCANINTERVAL);
realTimeLog = (Boolean)prefs.get(PREFERENCE_REALTIME);
// Get current background scan interval (if specified)
if (prefs.get(PREFERENCE_SCANINTERVAL) != null) {
beaconManager.setBackgroundBetweenScanPeriod(Long.parseLong(scanInterval));
}
logToDisplay("Scanning...");
// Initialise scan log
logString = new StringBuffer();
//Start scanning again.
beaconManager.setRangeNotifier(new RangeNotifier() {
#Override
public void didRangeBeaconsInRegion(Collection<Beacon> beacons, Region region) {
if (beacons.size() > 0) {
Iterator <Beacon> beaconIterator = beacons.iterator();
while (beaconIterator.hasNext()) {
Beacon beacon = beaconIterator.next();
// Debug - logging a beacon - checking background logging is working.
System.out.println("Logging another beacon.");
logBeaconData(beacon);
}
}
}
});
try {
beaconManager.startRangingBeaconsInRegion(region);
} catch (RemoteException e) {
// TODO - OK, what now then?
}
}
/**
* Stop looking for beacons.
*/
private void stopScanning(Button scanButton) {
try {
beaconManager.stopRangingBeaconsInRegion(region);
} catch (RemoteException e) {
// TODO - OK, what now then?
}
String scanData = logString.toString();
if (scanData.length() > 0) {
// Write file
fileHelper.createFile(scanData);
// Display file created message.
Toast.makeText(getBaseContext(),
"File saved to:" + getFilesDir().getAbsolutePath(),
Toast.LENGTH_SHORT).show();
scanButton.setText(MODE_STOPPED);
} else {
// We didn't get any data, so there's no point writing an empty file.
Toast.makeText(getBaseContext(),
"No data captured during scan, output file will not be created.",
Toast.LENGTH_SHORT).show();
scanButton.setText(MODE_STOPPED);
}
}
/**
*
* #return reference to the start/stop scanning button
*/
private Button getScanButton() {
return (Button)findViewById(R.id.scanButton);
}
/**
*
* #param beacon The detected beacon
*/
private void logBeaconData(Beacon beacon) {
StringBuilder scanString = new StringBuilder();
if (index) {
scanString.append(eventNum++);
}
if (beacon.getServiceUuid() == 0xfeaa) {
if (beacon.getBeaconTypeCode() == 0x00) {
scanString.append(" Eddystone-UID -> ");
scanString.append(" Namespace : ").append(beacon.getId1());
scanString.append(" Identifier : ").append(beacon.getId2());
logEddystoneTelemetry(scanString, beacon);
} else if (beacon.getBeaconTypeCode() == 0x10) {
String url = UrlBeaconUrlCompressor.uncompress(beacon.getId1().toByteArray());
scanString.append(" Eddystone-URL -> " + url);
} else if (beacon.getBeaconTypeCode() == 0x20) {
scanString.append(" Eddystone-TLM -> ");
logEddystoneTelemetry(scanString, beacon);
}
} else {
// Just an old fashioned iBeacon or AltBeacon...
logGenericBeacon(scanString, beacon);
}
logToDisplay(scanString.toString());
scanString.append("\n");
// Code added following a feature request by D.Schmid - writes a single entry to a file
// every time a beacon is detected, the file will only ever have one entry as it will be
// recreated on each call to this method.
// Get current background scan interval (if specified)
if (realTimeLog) {
// We're in realtime logging mode, create a new log file containing only this entry.
fileHelper.createFile(scanString.toString(), "realtimelog.txt");
}
logString.append(scanString.toString());
}
/**
* Logs iBeacon & AltBeacon data.
*/
private void logGenericBeacon(StringBuilder scanString, Beacon beacon) {
// Comment stuff out for whatever reason
/*
if (location) {
scanString.append(" Location: ").append(getCurrentLocation()).append(" ");
}
`
*/
if (uuid) {
scanString.append(" UUID: ").append(beacon.getId1());
if (beacon.getId1().equals("ffffffff-ffff-ffff-ffff-ffffffffffff ")){
scanString.append("WE DID IT!!!!!!!!!!!");
}else{
scanString.append(" WE DID NOT DO IT =( ");
}
/*
if ((beacon.getId1()).equals ("f")){
scanString.append("WE DID IT!!!!!!!!!!!");
}else{
scanString.append(" WE DID NOT DO IT!!!!!!!!!!! ");
}
*/
}
// Making if statements to test for advertising data
/*
if (majorMinor) {
scanString.append(" Maj. Mnr.: ");
if (beacon.getId2() != null) {
scanString.append(beacon.getId2());
}
scanString.append("-");
if (beacon.getId3() != null) {
scanString.append(beacon.getId3());
}
}
if (rssi) {
scanString.append(" RSSI: ").append(beacon.getRssi());
}
if (proximity) {
scanString.append(" Proximity: ").append(BeaconHelper.getProximityString(beacon.getDistance()));
}
if (power) {
scanString.append(" Power: ").append(beacon.getTxPower());
}
if (timestamp) {
scanString.append(" Timestamp: ").append(BeaconHelper.getCurrentTimeStamp());
} */
}
private void logEddystoneTelemetry(StringBuilder scanString, Beacon beacon) {
// Do we have telemetry data?
if (beacon.getExtraDataFields().size() > 0) {
long telemetryVersion = beacon.getExtraDataFields().get(0);
long batteryMilliVolts = beacon.getExtraDataFields().get(1);
long pduCount = beacon.getExtraDataFields().get(3);
long uptime = beacon.getExtraDataFields().get(4);
scanString.append(" Telemetry version : " + telemetryVersion);
scanString.append(" Uptime (sec) : " + uptime);
scanString.append(" Battery level (mv) " + batteryMilliVolts);
scanString.append(" Tx count: " + pduCount);
}
}
/**
*
* #param line
*/
private void logToDisplay(final String line) {
runOnUiThread(new Runnable() {
public void run() {
editText.append(line + "\n");
// Temp code - don't really want to do this for every line logged, will look for a
// workaround.
Linkify.addLinks(editText, Linkify.WEB_URLS);
scroller.fullScroll(View.FOCUS_DOWN);
}
});
}
private void verifyBluetooth() {
try {
if (!BeaconManager.getInstanceForApplication(this).checkAvailability()) {
final AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("Bluetooth not enabled");
builder.setMessage("Please enable bluetooth in settings and restart this application.");
builder.setPositiveButton(android.R.string.ok, null);
builder.setOnDismissListener(new DialogInterface.OnDismissListener() {
#Override
public void onDismiss(DialogInterface dialog) {
finish();
System.exit(0);
}
});
builder.show();
}
}
catch (RuntimeException e) {
final AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("Bluetooth LE not available");
builder.setMessage("Sorry, this device does not support Bluetooth LE.");
builder.setPositiveButton(android.R.string.ok, null);
builder.setOnDismissListener(new DialogInterface.OnDismissListener() {
#Override
public void onDismiss(DialogInterface dialog) {
finish();
System.exit(0);
}
});
builder.show();
}
}
/* Location services code follows */
#Override
protected void onStart() {
super.onStart();
// Connect the client.
locationClient.connect();
}
#Override
protected void onStop() {
// Disconnect the client.
locationClient.disconnect();
super.onStop();
}
#Override
public void onConnected(Bundle dataBundle) {
// Uncomment the following line to display the connection status.
// Toast.makeText(this, "Connected", Toast.LENGTH_SHORT).show();
}
#Override
public void onDisconnected() {
// Display the connection status
Toast.makeText(this, "Disconnected. Please re-connect.",
Toast.LENGTH_SHORT).show();
}
#Override
public void onConnectionFailed(ConnectionResult connectionResult) {
/* Google Play services can resolve some errors it detects.
* If the error has a resolution, try sending an Intent to
* start a Google Play services activity that can resolve
* error.
*/
if (connectionResult.hasResolution()) {
try {
// Start an Activity that tries to resolve the error
connectionResult.startResolutionForResult(
this,
CONNECTION_FAILURE_RESOLUTION_REQUEST);
/*
* Thrown if Google Play services canceled the original
* PendingIntent
*/
} catch (IntentSender.SendIntentException e) {
// Log the error
e.printStackTrace();
}
} else {
/*
* If no resolution is available, display a dialog to the
* user with the error.
*/
Toast.makeText(getBaseContext(),
"Location services not available, cannot track device location.",
Toast.LENGTH_SHORT).show();
}
}
// Define a DialogFragment that displays the error dialog
public static class ErrorDialogFragment extends DialogFragment {
// Global field to contain the error dialog
private Dialog mDialog;
// Default constructor. Sets the dialog field to null
public ErrorDialogFragment() {
super();
mDialog = null;
}
// Set the dialog to display
public void setDialog(Dialog dialog) {
mDialog = dialog;
}
// Return a Dialog to the DialogFragment.
#Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
return mDialog;
}
}
/*
* Handle results returned to the FragmentActivity
* by Google Play services
*/
#Override
protected void onActivityResult(
int requestCode, int resultCode, Intent data) {
// Decide what to do based on the original request code
switch (requestCode) {
case CONNECTION_FAILURE_RESOLUTION_REQUEST :
/*
* If the result code is Activity.RESULT_OK, try
* to connect again
*/
switch (resultCode) {
case Activity.RESULT_OK :
/*
* TODO - Try the request again
*/
break;
}
}
}
}
Need to cast to string first .toString
if (uuid) {
scanString.append(" UUID: ").append(beacon.getId1());
// Making if statements to look for all f's in advertising data
if (beacon.getId1().toString().equals(Str1)){
scanString.append("\nAlarm ACTIVATED\n");
}else{
scanString.append("\n Alarm NOT active\n");
}
}
i am trying out below code everything works fine when net is connected
here is the workflow
there is a main activity from where on button click this activity should open
it would do the parsing part and then go to next list activity.in case there is a back press or this activity is closed the asynctask should stop using
loader.cancel(true);
this would work perfectly if net is available and tested the issue happens when dont have internet connection
the alert box shows and it goes to the first activity then it crashes
i want the alert box to show and app should not crash and go back to first -->mainactivity
i have refereed this
http://techiedreams.com/android-simple-rss-reader/
How to end AsyncTask onBackPress()
import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.net.ConnectivityManager;
import android.os.AsyncTask;
import android.os.Bundle;
import com.parser.DOMParser;
import com.parser.RSSFeed;
public class SplashActivity extends Activity {
//private String RSSFEEDURL = "http://www.mobilenations.com/rss/mb.xml";
RSSFeed feed;
private AsyncLoadXMLFeed loader;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.splash);
Intent i = getIntent();
int position = i.getExtras().getInt("position");
String[] country = i.getStringArrayExtra("country");
//Toast.makeText(getApplicationContext(), country[position], Toast.LENGTH_SHORT).show();
//Toast.makeText(getApplicationContext(), country[position], Toast.LENGTH_SHORT).show();
String name = i.getStringExtra("name");
//Toast.makeText(getApplicationContext(), name, Toast.LENGTH_SHORT).show();
ConnectivityManager conMgr = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
if (conMgr.getActiveNetworkInfo() == null) {
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setMessage(
"Unable to reach server, \nPlease check your connectivity.")
.setTitle("TD RSS Reader")
.setCancelable(false)
.setPositiveButton("Exit",
new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog,
int id) {
//loader.cancel(true);
finish();
}
});
AlertDialog alert = builder.create();
alert.show();
} else {
// Connected - Start parsing
loader = new AsyncLoadXMLFeed();
loader.execute();
//new AsyncLoadXMLFeed().execute();
}
}
private class AsyncLoadXMLFeed extends AsyncTask<Void, Void, Void>{
#Override
protected Void doInBackground(Void... params) {
// Obtain feed
DOMParser myParser = new DOMParser();
Intent i = getIntent();
int position = i.getExtras().getInt("position");
String[] country = i.getStringArrayExtra("country");
String name = i.getStringExtra("name");
//feed = myParser.parseXml(RSSFEEDURL);
feed = myParser.parseXml("http://"+name+".blogspot.com//feeds/posts/default/-/" + country[position] + "?alt=rss");
return null;
}
#Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
Bundle bundle = new Bundle();
bundle.putSerializable("feed", feed);
// launch List activity
Intent intent = new Intent(SplashActivity.this, ListActivity.class);
intent.putExtras(bundle);
startActivity(intent);
// kill this activity
finish();
}
}
#Override
public void onBackPressed() {
finish();
}
#Override
public void onDestroy(){
super.onDestroy();
// Cancel the task
loader.cancel(true);
}
My guess it crashes with NullPointerException.
It is because if you don't have network connectivity you don't create AsyncLoadXMLFeed instance.
So when onDestroy() happened and you call loader.cancel(true); it throws this Exception.
finally did this
thanks anatol needed to check loader != null
#Override
public void onDestroy(){
super.onDestroy();
// Cancel the task
if(loader != null && loader.getStatus() != AsyncTask.Status.FINISHED) {
loader.cancel(true);
}
//loader.cancel(true);
}
The best and simplest solution for handle this issue is that use try catch block in your onPost execute() in async task. like this
#Override
protected void onPostExecute(String s) {
try {
super.onPostExecute(s);
loading.dismiss();
}catch (Exception ex){
Toast.makeText(UserLogin.this, "Something is going wrong, please try again!", Toast.LENGTH_LONG).show();
}
}
simply this will prevent your app from crash.
I am using the following code to make the android device a ftp server (Android Internal storage). I am getting the exception of os.android.NetworkOnMainThread. I have tried to put the onStart code in the AsyncTask but app never executes and crashes on launch. Any help regarding the ftp server on Android will be great as i have no idea how to get it working.
Here is the MainActivity Code
package com.googlecode.simpleftp;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.Dialog;
import android.content.Context;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.widget.TextView;
import android.widget.Toast;
public class FTPServer extends Activity {
private static int COMMAND_PORT = 2121;
static final int DIALOG_ALERT_ID = 0;
private static ExecutorService executor = Executors.newCachedThreadPool();
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.my_menu, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle item selection
switch (item.getItemId()) {
case R.id.new_game:
System.out.println("New game button is pressed!");
//newGame();
return true;
case R.id.quit:
System.out.println("Quit button is pressed!");
showDialog(DIALOG_ALERT_ID);
return true;
default:
return super.onOptionsItemSelected(item); }
}
#Override
protected Dialog onCreateDialog(int id){
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setMessage("Are you sure you want to exit?")
.setCancelable(false).setPositiveButton("yes", new DialogInterface.OnClickListener(){
#Override
public void onClick(DialogInterface dialog, int id){
FTPServer.this.finish();
}
})
.setNegativeButton("No", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
AlertDialog alert = builder.create();
return alert;
}
HEre is the ServerPI Code
import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;
public class ServerPI implements Runnable{
private Socket clientSocket;
private BufferedReader in;
private PrintWriter out;
private String baseDir;
private String relativeDir;
private String absoluteDir;
private String fileName;
private String filePath;
public ServerPI(Socket incoming) throws IOException{
this.clientSocket = incoming;
in = new BufferedReader(new InputStreamReader(this.clientSocket.getInputStream()));
out = new PrintWriter(this.clientSocket.getOutputStream(), true);
baseDir = new File("").getAbsolutePath();
relativeDir = "/";
absoluteDir = baseDir + relativeDir;
fileName = "";
filePath = absoluteDir + "/" + fileName;
}
private void readCommandLoop() throws IOException {
String line = null;
reply(220, "Welcome to the SimpleFTP server!");
while((line = in.readLine()) != null){
int replyCode = executeCommand(line.trim());
if(replyCode == 221){
return;
}
}
}
private int executeCommand(String trim) {
// TODO Auto-generated method stub
return 0;
}
public int reply(int statusCode, String statusMessage){
out.println(statusCode + " " + statusMessage);
return statusCode;
}
#Override
public void run(){
try{
this.readCommandLoop();
} catch (IOException e){
e.printStackTrace();
}
finally {
try {
if(in != null){
in.close();
in = null;
}
if(out != null){
out.close();
out = null;
}
if (clientSocket != null){
clientSocket.close();
clientSocket = null;
}
}
catch (IOException e){
e.printStackTrace();
}
}
}
}
I have put the code in the AsyncTask, here it is
private class LongOperation extends AsyncTask<String, Void, String> {
#Override
protected String doInBackground(String... params) {
ServerSocket s = null;
Socket incoming = null;
try{
s = new ServerSocket(COMMAND_PORT);
String ip = (s.getInetAddress()).getHostAddress();
Context context = this.getApplicationContext();
CharSequence text = ip;
int duration = Toast.LENGTH_LONG;
Toast toast = Toast.makeText(context, text, duration);
Thread.sleep(1000);
toast.show();
while(true){
incoming = s.accept();
executor.execute(new ServerPI(incoming));
}
}
catch(Exception e){
System.out.println(e.toString());
e.printStackTrace();
}
finally{
try
{
if(incoming != null)incoming.close();
}
catch(IOException ignore)
{
//ignore
}
try
{
if (s!= null)
{
s.close();
}
}
catch(IOException ignore)
{
//ignore
}
}
return "Executed";
}
#Override
protected void onPostExecute(String result) {
}
#Override
protected void onPreExecute() {
}
#Override
protected void onProgressUpdate(Void... values) {
}
}
Iam calling the longOpertation in onCreate method. What is the problem that the app crashes on launch.
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_fullscreen);
new LongOperation().execute();
}
Maybe because you didn't set up the permissions in the manifest? You've to set permission for internet usage.
If this doesn't work, please tell us which line is it throwing the exception.
while(true){ incoming = s.accept(); ...} You cannot put that in OnStart(). That should be done in a thread. So ServerSocket s = null; should be a variable of you activity.
So I went with Swiftp application (open source) as a service in my application which helped me to achieve my task. Thanks everyone who stepped forward to help. Here is the link if someone wants to follow
Please post your code here.
NetworkOnMainthreadException occurs because you maybe running Network related operation on the Main UI Thread. You should use asynctask for this purpose
This is only thrown for applications targeting the Honeycomb SDK or higher. Applications targeting earlier SDK versions are allowed to do networking on their main event loop threads, but it's heavily discouraged.
http://developer.android.com/reference/android/os/NetworkOnMainThreadException.html
class TheTask extends AsyncTask<Void,Void,Void>
{
protected void onPreExecute()
{ super.onPreExecute();
//display progressdialog.
}
protected void doInBackground(Void ...params)//return result here
{
//http request. do not update ui here
//call webservice
//return result here
return null;
}
protected void onPostExecute(Void result)//result of doInBackground is passed a parameter
{
super.onPostExecute(result);
//dismiss progressdialog.
//update ui using the result returned form doInbackground()
}
}
http://developer.android.com/reference/android/os/AsyncTask.html. Check the topic under the heading The 4 Steps.
A working example of asynctask # To use the tutorial in android 4.0.3 if had to work with AsynxTasc but i still dont work?.
The above makes a webserive call in doInBakckground(). Returns result and updates the ui by setting the result in textview in onPostExecute().
You can not do network operation in main thread in android 3.0 higher. Use AsyncTask for this network operation. See this for further explanation
i got a class i made, that makes a simple GET request and displays toast messege with the response...
if i call the function from a bottom event click it displays the messege with the data returned, just ok.
but if i call the same function from a brodcast reciver class, it just showing the massege with the data '' (null)
i belive that it showing the massege before i could get the data, and with the button it waits for the data..
how can i make it work from the brodcast reciver?
the class:
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import android.app.Activity;
import android.content.Context;
import android.widget.Toast;
public class myclass{
public static void doHttpRequest(String param1, Context context){
String ret="";
try {
URL url = new URL("http://website.com/page?param="+param1);
HttpURLConnection con = (HttpURLConnection) url
.openConnection();
ret=readStream(con.getInputStream());
} catch (Exception e) {
e.printStackTrace();
}
CharSequence text = "return data- "+ret;
int duration = Toast.LENGTH_LONG;
Toast toast = Toast.makeText(context, text, duration);
toast.show();
}
private static String readStream(InputStream in) {
BufferedReader reader = null;
String line = "";
String alllines = "";
try {
reader = new BufferedReader(new InputStreamReader(in));
while ((line = reader.readLine()) != null) {
alllines=alllines+line;
}
return alllines;
} catch (IOException e) {
e.printStackTrace();
} finally {
if (reader != null) {
try {
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return alllines;
}
}
from the button it works fine:
final Button button = (Button) findViewById(R.id.button1);
button.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
myclass.doHttpRequest("blabla", getBaseContext());
}});
from the brodcast reciver witch in different class it won't return data, but shows the toast..
public class CustomBroadcastReceiver extends BroadcastReceiver {
private static final String TAG = "CustomBroadcastReceiver";
#Override
public void onReceive(Context context, Intent intent) {
myclass.doHttpRequest("blabla", context);
break;
} }
}
please HELP.... :) THANKS
All fixed.. it's seems to be a project settings error, or premmisions error (but i had the premissions in the manifest... must not apply in the apk while compiling)
i copied the classes to enother project made by erlier version of eclipse, and it's works there like a charm...
thanks anyway..
i tried for hours to fix it in the code.. and it was the settings....
I created a myclass.java and CustomBroadcastReceiver.java and tried your code by removing the break statement and one extra curly brace from the CustomBroadcastReceiver.java class and it worked fine for me.
The following code in Activity class demonstrates registering, uninteresting receiver and a Handler for a sample/test broadcast.
CustomBroadcastReceiver customBroadcastReceiver;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
customBroadcastReceiver = new CustomBroadcastReceiver();
registerReceiver(cusoBroadcastReceiver, new IntentFilter("com.example.app.testbroadcast"));
// For test broadcast only.
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
// TODO Auto-generated method stub
sendBroadcast(new Intent("com.example.app.testbroadcast"));
}
}, 2000);
}
#Override
protected void onDestroy() {
// TODO Auto-generated method stub
super.onDestroy();
unregisterReceiver(customBroadcastReceiver);
}
Hope this helps.