Database Users

Newbie url text download problem

Hi guys,
I am totally new at this. I mean completely raw .
I successfully put together a searchlight project by following a tutorial on youtube.
Now I want to do some work on a project that will fetch information from my employers website into the app. This information will be inform of text and images.
Here's the code I'm using in my attempt to read the remote text:
Code:
try {
URL url = new URL( "fullpath-url-to-file-dot-php" );
URLConnection conn = url.openConnection();
// Get the response
BufferedReader rd = new BufferedReader(new InputStreamReader(conn.getInputStream()));
String line = "";
while ((line = rd.readLine()) != null) {
Message lmsg;
lmsg = new Message();
lmsg.obj = line;
lmsg.what = 0;
Context context = getApplicationContext();
CharSequence text = "Hello toast! "+lmsg;
int duration = Toast.LENGTH_LONG;
Toast toast = Toast.makeText(context, text, duration);toast.show();
}
} catch (IOException e) {
// TODO Auto-generated catch block
//e.printStackTrace();
Context context = getApplicationContext();
CharSequence text = "error!";
int duration = Toast.LENGTH_LONG;
Toast toast = Toast.makeText(context, text, duration);toast.show();
}
I admit I barely know what I am doing. My attempt to download a simple line of text from a website url keeps failing.
Anyway, Can you guys give me an idea what I am doing wrong and what I should be doing instead?
Thanks

Update
I found out what the nature of the exception is.
It's a
Code:
java.net.socketexception: permission denied
exception.
Can anyone please shed some light on this for me ?

Did you add the internet permission to your manifest file?
Should be something like
<uses-permission>android.permission.INTERNET</uses-permission>

More secure encryption class using salt

Continuing with the theme from my last thread where I posted a simple class for encrypting strings using the SHA-512 hashing algorithm, here is an improved version that generates a random 20 byte salt to add in with the string to be hashed. This is then hashed providing greater security.
Due to the random generation of the salt each time a string is hashed, this makes it pretty much impossible to get the same hash for a string, therefore once the salt has been generated the first time round it is stored in sharedPreferences for future uses so that you can use it for checking matches etc
Method of converting the bytes to hex string adapted from maybeWeCouldStealAVan's method @ stackoverflow.
Code:
public class Crypto {
final protected static char[] hexArray = "0123456789ABCDEF".toCharArray();
protected static String SHA512(String string, Context context) throws NoSuchAlgorithmException {
MessageDigest md = MessageDigest.getInstance("SHA-512");
String salt = getSalt(context);
md.update(salt.getBytes());
byte[] bytes = md.digest(string.getBytes());
char[] hexChars = new char[bytes.length * 2];
for (int j = 0; j < bytes.length; j++) {
int v = bytes[j] & 0xFF;
hexChars[j * 2] = hexArray[v >>> 4];
hexChars[j * 2 + 1] = hexArray[v & 0x0F];
}
return new String(hexChars);
}
private static String getSalt(Context context) throws NoSuchAlgorithmException {
SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(context);
String salt = preferences.getString("salt", null);
if (salt == null) {
byte[] saltBytes = new byte[20];
SecureRandom.getInstance("SHA1PRNG").nextBytes(saltBytes);
salt = new String(saltBytes);
SharedPreferences.Editor editor = preferences.edit();
editor.putString("salt", salt).commit();
}
return salt;
}
}
Usage:
Code:
String example = "example";
try {
example = Crypto.SHA512(example, context);
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
}

Thanks for sharing, it's quite usefull ! I will include it to my project

Jonny said:
Continuing with the theme from my last thread where I posted a simple class for encrypting strings using the SHA-512 hashing algorithm, here is an improved version that generates a random 20 byte salt to add in with the string to be hashed. This is then hashed providing greater security.
Due to the random generation of the salt each time a string is hashed, this makes it pretty much impossible to get the same hash for a string, therefore once the salt has been generated the first time round it is stored in sharedPreferences for future uses so that you can use it for checking matches etc
Method of converting the bytes to hex string adapted from maybeWeCouldStealAVan's method @ stackoverflow.
Code:
public class Crypto {
final protected static char[] hexArray = "0123456789ABCDEF".toCharArray();
protected static String SHA512(String string, Context context) throws NoSuchAlgorithmException {
MessageDigest md = MessageDigest.getInstance("SHA-512");
String salt = getSalt(context);
md.update(salt.getBytes());
byte[] bytes = md.digest(string.getBytes());
char[] hexChars = new char[bytes.length * 2];
for (int j = 0; j < bytes.length; j++) {
int v = bytes[j] & 0xFF;
hexChars[j * 2] = hexArray[v >>> 4];
hexChars[j * 2 + 1] = hexArray[v & 0x0F];
}
return new String(hexChars);
}
private static String getSalt(Context context) throws NoSuchAlgorithmException {
SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(context);
String salt = preferences.getString("salt", null);
if (salt == null) {
byte[] saltBytes = new byte[20];
SecureRandom.getInstance("SHA1PRNG").nextBytes(saltBytes);
salt = new String(saltBytes);
SharedPreferences.Editor editor = preferences.edit();
editor.putString("salt", salt).commit();
}
return salt;
}
}
Usage:
Code:
String example = "example";
try {
example = Crypto.SHA512(example, context);
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
}
Click to expand...
Click to collapse
Thanks
Gesendet von meinem LG-D855 mit Tapatalk

How do I implement a onscroll Listener to my listview?

I have a large data to load from JSON.
I have implemented a custom list view by following a tutorial, now since the data is huge I want it load as the user scrolls.
This is my LoadRestaurant class code which is inside the main activity.
Code:
class LoadRestaurants extends AsyncTask<String, String, String> {
//Show Progress Dialog
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(SearchAll.this);
pDialog.setMessage("Loading All Restaurants...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(false);
pDialog.show();
}
protected String doInBackground(String... arg) {
//building parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
//Getting JSON from URL
String json = jsonParser.makeHttpRequest(URL_RESTAURANT_LIST, "GET", params);
//Log Cat Response Check
Log.d("Areas JSON: ", "> " + json);
try {
restaurants = new JSONArray(json);
if (restaurants != null) {
//loop through all restaurants
for (int i = 0; i < restaurants.length(); i++) {
JSONObject c = restaurants.getJSONObject(i);
//Storing each json object in the variable.
String id = c.getString(TAG_ID);
String name = c.getString(TAG_NAME);
String location = c.getString(TAG_LOCATION);
String rating = c.getString(TAG_RATING);
//Creating New Hashmap
HashMap<String, String> map = new HashMap<String, String>();
//adding each child node to Hashmap key
map.put(TAG_ID, id);
map.put(TAG_NAME, name);
map.put(TAG_LOCATION, location);
map.put(TAG_RATING, rating);
//adding HashList to ArrayList
restaurant_list.add(map);
}
}
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
protected void onPostExecute(String file_url) {
//dismiss the dialog
pDialog.dismiss();
//Updating UI from the Background Thread
runOnUiThread(new Runnable() {
@Override
public void run() {
ListAdapter adapter = new SimpleAdapter(
SearchAll.this, restaurant_list,
R.layout.listview_restaurants, new String[]{
TAG_ID, TAG_NAME, TAG_LOCATION, TAG_RATING}, new int[]{
R.id.login_id, R.id.restaurant_name, R.id.address, R.id.rating});
setListAdapter(adapter);
ListView lv = getListView();
lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
// Bundle bundle = new Bundle();
Intent intent = new Intent(SearchAll.this, RestaurantProfile.class);
String loginId = ((TextView) view.findViewById(R.id.login_id)).getText().toString();
intent.putExtra("login_id", loginId);
startActivity(intent);
}
});
}
});
}
}
}
I want to load around 20 restaurants and then it auto loads another 20 as soon as user reaches the end of first 20.
There are lots of tutorials online but its confusing to implement.
Please help me out!

The custom ListView, support for automatic loading you can try https://github.com/chrisbanes/Android-PullToRefresh

Starting chronometer with if condition comparing strings

I have an android application that is receiving a string from an arduino via Bluetooth, names the string "data" and displays it by setting a TextView to the string "data". I want a chronometer to start when the incoming string matches a predefined string.
For example:
Code:
if data.equals(startChrono)){
chronometerLeft.setBase(SystemClock.elapsedRealtime());
chronometerLeft.start();
I actually have the arduino sending a "g" and am setting my string goL to be "g" but cannot get the chronometer to start when the g is received. My TextView shows the g. Code is below. I've tried several things and at a loss. Using same code for chronometer.start() with onClickListener with a button works great. I just need it to start the chronometer when i receive a specific string from the arduino.
Code:
beginListenForData();
// text.setText("Bluetooth Opened");
}
void beginListenForData() {
final Handler handler = new Handler();
final byte delimiter = 10; // This is the ASCII code for a newline
// character
stopWorker = false;
readBufferPosition = 0;
readBuffer = new byte[1024];
workerThread = new Thread(new Runnable() {
public void run() {
while (!Thread.currentThread().isInterrupted() && !stopWorker) {
try {
int bytesAvailable = mmInputStream.available();
if (bytesAvailable > 0) {
byte[] packetBytes = new byte[bytesAvailable];
mmInputStream.read(packetBytes);
for (int i = 0; i < bytesAvailable; i++) {
byte b = packetBytes[i];
if (b == delimiter) {
byte[] encodedBytes = new byte[readBufferPosition];
System.arraycopy(readBuffer, 0,
encodedBytes, 0,
encodedBytes.length);
final String data = new String(
encodedBytes, "US-ASCII");
readBufferPosition = 0;
handler.post(new Runnable() {
public void run() {
text.setText(data);
String goL = "g";
String goR = "f";
chronometerLeft = (Chronometer)findViewById(R.id.chronometerLeft);
chronometerRight = (Chronometer)findViewById(R.id.chronometerRight);
if(data.equals(goL)){
chronometerLeft.setBase(SystemClock.elapsedRealtime());
chronometerLeft.start();
if(data.equals(goR))
chronometerRight.setBase(SystemClock.elapsedRealtime());
chronometerRight.start();
}
}
});
} else {
readBuffer[readBufferPosition++] = b;
}
}
}
} catch (IOException ex) {
stopWorker = true;
}
}
}
});
workerThread.start();
}

Sorry to bother, but in your while loop condition, what does the '!' before Thread do?

Help with Apple WeatherKit

I hope someone can help me.
I'm having trouble getting an Apple WeatherKit REST request working. I'm trying to follow all of the requirements listed on https://developer.apple.com/documen...equest_authentication_for_weatherkit_rest_api, but I still get a 403 response code -- and I can't locate any Java samples to follow. I've been sweating this for weeks and haven't gotten anywhere.
Here's what I have:
URL url = new URL ("https://weatherkit.apple.com/api/v1/weather/en/40.75/-73.00?dataSets=currentWeather&timezone=Europe/London");
PrivateKey pkey = getPrivateKey ("AuthKey_CXXXXXXXXX.p8");
String jwts = getJwtsString (pkey);
HttpURLConnection conn = getConnection (url, jwts);
conn.connect();
int responsecode = conn.getResponseCode();
Just in case I've got something wrong, here are the three functions I'm calling. First, the one that creates the PrivateKey from the p8 file (I'm pretty sure this one is OK):
private PrivateKey getPrivateKey (String filename) {
PrivateKey privateKey = null;
try {
AssetManager assetManager = this.getAssets();
InputStream stream = assetManager.open(filename);
byte[] bytes = new byte[stream.available()];
int bytesRead = stream.read(bytes);
byte[] pkcs8EncodedKey = new byte[0];
pkcs8EncodedKey = Base64.getDecoder().decode(bytes);
KeyFactory factory = KeyFactory.getInstance("EC");
privateKey = factory.generatePrivate(new PKCS8EncodedKeySpec(pkcs8EncodedKey));
} catch (Exception e) { }
return privateKey;
}
Next, creating the JWTS string:
private String getJwtsString(PrivateKey privateKey) {
long t1 = System.currentTimeMillis();
return Jwts.builder()
.setHeaderParam ("alg", "ES256")
.setHeaderParam ("kid", "CXXXXXXXXX")
.setHeaderParam ("id", "QXXXXXXXXX.com.mydomain.myproject")
.claim ("iss", "Q5DC438ZG4")
.claim ("iat", t1)
.claim ("exp", t1 + 60000)
.claim ("sub", "com.mydomain.myproject") // obviously, replaced with my project info
.signWith (privateKey, SignatureAlgorithm.ES256)
.compact ();
}
And finally, creating the connection:
private HttpURLConnection getConnection(URL url, String jws) {
HttpURLConnection conn = (HttpURLConnection) Objects.requireNonNull(url).openConnection();
conn.setRequestMethod ("GET")
conn.setRequestProperty ("Authorization", "Bearer "+ jws);
conn.setRequestProperty ("Content-Type", "application/x-www-form-urlencoded");
conn.setRequestProperty ("Content-Language", "en-US");
conn.setUseCaches (false);
conn.setDoInput (true);
conn.setDoOutput (true);
conn.setConnectTimeout (30000); //set timeout to 30 seconds
return conn;
}
Obviously, this is the first time I've tried creating an authenticated http call, so I wouldn't be at all surprised if this is wrong.
Can anybody supply some sample code that I could follow?
Thanks in advance...