Develop Reference

payUmoney integration is giving an error

After logging in, it's generating a hash value, but still giving error "Some problem occurred! try again".
PayUmoneySdkInitilizer.PaymentParam.Builder builder =
new PayUmoneySdkInitilizer.PaymentParam.Builder();
builder.setAmount(10.0)
.setTnxId("0nf7" + System.currentTimeMillis())
.setPhone(<My phone>)
.setProductName("product_name")
.setFirstName(<My Name>)
.setEmail(<My email>)
.setsUrl("https://www.payumoney.com/mobileapp/payumoney/success.php")
.setfUrl("https://www.payumoney.com/mobileapp/payumoney/failure.php")
.setUdf1("").setUdf2("").setUdf3("").setUdf4("").setUdf5("")
.setIsDebug(false)
.setKey(<mykey>)
.setMerchantId(<my debug merchant id>);
String tnxId="0nf7" + System.currentTimeMillis();
PayUmoneySdkInitilizer.PaymentParam paymentParam = builder.build();
String hashSequence = "<...>|"+tnxId+"|10.0|product_name|<My name>|<My email>|||||||||||salt";
String serverCalculatedHash= hashCal("SHA-512", hashSequence);
Toast.makeText(getApplicationContext(),
serverCalculatedHash, Toast.LENGTH_SHORT).show();
paymentParam.setMerchantHash(serverCalculatedHash);
// calculateServerSideHashAndInitiatePayment(paymentParam);
PayUmoneySdkInitilizer.startPaymentActivityForResult(TrayActivity.this, paymentParam);
public static String hashCal(String type, String str) {
byte[] hashseq = str.getBytes();
StringBuffer hexString = new StringBuffer();
try {
MessageDigest algorithm = MessageDigest.getInstance(type);
algorithm.reset();
algorithm.update(hashseq);
byte messageDigest[] = algorithm.digest();
for (int i = 0; i<messageDigest.length; i++) {
String hex = Integer.toHexString(0xFF &messageDigest[i]);
if (hex.length() == 1) { hexString.append("0"); }
hexString.append(hex);
}
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
} return hexString.toString();
}

You use in the code:
.setTnxId("0nf7" + System.currentTimeMillis())
And then later:
String tnxId="0nf7" + System.currentTimeMillis();
Probably not the only problem, but do you really want to use two different values for these (the time may change between the two calls)? Didn't you want the same tnxId in both cases?
TransactionIdProvider.java:
import java.util.Locale;
public class TransactionIdProvider {
private final static String DEFAULT_PREFIX = "ID";
// Convenient prime number for incrementing the counter
private final static long ID_ADD = 0xF0AD; // "f*ck off and die"
// 64b counter with non-trivial start value
private static long idCounter = 0x0101F00DDEADBEEFL;
/**
* Returns ID consisting of prefix string and 64b counter interleaved
* with 32b per-4s-timestamp.
*
* May produce identical ID (collision) when:
* 1) class is reloaded within 4s
* (to fix: serialize "idCounter" upon shutdown/restart of VM, or
* modify prefix per start of VM)
* 2) more than 2^64 IDs are requested within 4s (no fix, unexpected)
* 3) more than 2^64 IDs are requested after cca. 550 years.
* (no fix, unexpected)
* 4) more than one static instance of TransactionIdProvider is used
* (two or more VMs running the app) (to fix put different prefix in
* every VM/server running this)
*
* Length of returned ID is prefix.length() + 24 alphanumeric symbols.
*/
public static synchronized String getNewId(final String prefix) {
idCounter += ID_ADD; // increment counter
// get 32b timestamp per ~4s (millis/4096) (good for ~550 years)
final int timeStamp = (int)(System.currentTimeMillis()>>12);
final int idPart1 = (int)(idCounter>>32);
final int idPart2 = (int)(idCounter);
return String.format(Locale.US, "%s%08X%08X%08X",
prefix, idPart1, timeStamp, idPart2);
}
public static String getNewId() {
return getNewId(DEFAULT_PREFIX);
}
}
Not sure how much usable is this one, and if the ID may be so long. Feel free to use/modify it any way you wish.
Also I wonder, whether I didn't forget about something important, but can't recall anything.
The security aspect of this one is still quite weak, as within 4s time span the ID will be like simple addition, but at least it's not producing 1, 2, 3... series.
Did found some SDK docs, looks like txnId may be 25 chars long, so you have 1 char for prefix only. Or cut down on timestamp, using %07X in format and masking value with 0x0FFFFFFF, that would make it repeat every ~34 years -> 2 letters for prefix. Or change counter to 32b int, should be still more than enough, unless you expect thousands of transactions per second -> that would remove 8 chars. Or base32/base64 the whole ID to shorten it (depends what alphabet is legal for content)...
Or whatever... already spent enough time with this. Hire a pro.

Android edit/insert into string

I was wondering how I could programmatically edit strings in android. I am displaying strings from my device to my website, and the apostrophes ruin the PHP output. so in order to fix this, I needed to add character breaks, ie: the backslash '\'.
For example, if I have this string: I love filiberto's!
I need android to edit it to: I love filiberto\'s!
However, each string is going to be different, and there will also be other characters that I have to escape from . How can I do this?
I was wondering how I could programmatically edit strings in android. I am displaying strings from my device to my website, and the apostrophes ruin the PHP output. so in order to fix this, I needed to add character breaks, ie: the backslash '\'.
This is what I have so far, thanks to ANJ for base code...:
if(title.contains("'")) {
int i;
int len = title.length();
char[] temp = new char[len + 1]; //plus one because gotta add new
int k = title.indexOf("'"); //location of apostrophe
for (i = 0; i < k; i++) { //all the letters before the apostrophe
temp[i] = title.charAt(i); //assign letters to array based on index
}
temp[k] = 'L'; // the L is for testing purposes
for (i = k+1; i == len; i++) { //all the letters after apostrophe, to end
temp[i] = title.charAt(i); //finish the original string, same array
}
title = temp.toString(); //output array to string (?)
Log.d("this is", title); //outputs gibberish
}
Which outputs random characters.. not even similar to my starting string. Does anyone know what could be causing this? For example, the string "Lol'ok" turns into >> "%5BC%4042ed0380"

I am assuming you are storing the string somewhere. Lets say the string is: str.
You can use a temporary array to add the '/'. For a single string:
int len = str.length();
char [] temp = new char[len+1]; //Temporary Array
int k = str.indexOf("'"), i; //Finding index of "'"
for(i=0; i<k-1; i++)
{
temp[i] = str.charAt(i); //Copying the string before '
}
temp[k] = '/'; //Placing "/" before '
for(i=k; j<len; j++)
{
temp[i+1] = str.charAt(i); //Copying rest of the string
}
String newstr = temp.toString(); //Converting array to string
You can use the same for multiple strings. Just make it as a function and call it whenever you want.

The String API has a number of API calls that could help, for example String.replaceAll. But...
apostrophes ruin the PHP output
Then fix the PHP code rather than require "clean" input. Best option would be to select a well supported transport format (say JSON or XML) and let the Json API on each end handle escape code.

Android Bluetooth and sending an unsigned Hex value

I am currently working on a Android application that takes values from a text box and then sends it over bluetooth, all operations are in Hex values.
I have a convertion method that can take the string make give me the unsigned integer for the string, but once i place it in the byte array it becomes signed and the board that receives this cannot do signed hex.
This is how the process works:
//sample string to send
String toSend = "0BDD";
//sending the byte[] to the board over bluetooth
btOutputStream.write(SendByteData(toSend));
// --- perform the conversion to byte[] ---
public static byte[] SendByteData(String hexString)
{
byte[] sendingThisByteArray = new byte[hexString.length()/2];
int count = 0;
for( int i = 0; i < hexString.length() - 1; i += 2 )
{
//grab the hex in pairs
String output = hexString.substring(i, (i + 2));
//convert the 2 characters in the 'output' string to the hex number
int decimal = (int)(Integer.parseInt(output, 16)) ;
//place into array for sending
sendingThisByteArray[count] = (byte)(decimal);
Log.d(TAG, "in byte array = " + sendingThisByteArray[count]);
count ++;
}
return sendingThisByteArray;
}
The issue is as follows:
When the for for loop runs through the string and picks up "0B" it correctly gives me integer 11; then when the loop runs through "DD" it give me integer 221 which is also correct
When I perform the operation of
sendingThisByteArray[count] = (byte)(decimal);
11 gets correctly placed in sendingThisByteArray[0]
but for sendingThisByteArray[1] the number 221 gets changed to -35
I know that Java has signed bytes.. is there a way to put/place/change the byte array so i can place and number 221 or any other value higher than 127?
your help is greatly appreciated

You can convert from a signed integer to unsigned byte like this, by binary AND'ing it with 0xFF:
sendingThisByteArray[count] = (byte)(decimal & 0xFF);
This way you can send values from 0 to 255

I found the problem, when i tried to do unsigned hex into a byte array it would always put a sign, i had to create single byte to retain the unsigned hex
int zeroA = (int)(Integer.parseInt("0D", 16));
sendStream.write(unsignedToBytes((byte) zeroA));

Android - How to filter emoji (emoticons) from a string?

I'm working on an Android app, and I do not want people to use emoji in the input.
How can I remove emoji characters from a string?

Emojis can be found in the following ranges (source) :
U+2190 to U+21FF
U+2600 to U+26FF
U+2700 to U+27BF
U+3000 to U+303F
U+1F300 to U+1F64F
U+1F680 to U+1F6FF
You can use this line in your script to filter them all at once:
text.replace("/[\u2190-\u21FF]|[\u2600-\u26FF]|[\u2700-\u27BF]|[\u3000-\u303F]|[\u1F300-\u1F64F]|[\u1F680-\u1F6FF]/g", "");

Latest emoji data can be found here:
http://unicode.org/Public/emoji/
There is a folder named with emoji version.
As app developers a good idea is to use latest version available.
When You look inside a folder, You'll see text files in it.
You should check emoji-data.txt. It contains all standard emoji codes.
There are a lot of small symbol code ranges for emoji.
Best support will be to check all these in Your app.
Some people ask why there are 5 digit codes when we can only specify 4 after \u.
Well these are codes made from surrogate pairs. Usually 2 symbols are used to encode one emoji.
For example, we have a string.
String s = ...;
UTF-16 representation
byte[] utf16 = s.getBytes("UTF-16BE");
Iterate over UTF-16
for(int i = 0; i < utf16.length; i += 2) {
Get one char
char c = (char)((char)(utf16[i] & 0xff) << 8 | (char)(utf16[i + 1] & 0xff));
Now check for surrogate pairs. Emoji are located on the first plane, so check first part of pair in range 0xd800..0xd83f.
if(c >= 0xd800 && c <= 0xd83f) {
high = c;
continue;
}
For second part of surrogate pair range is 0xdc00..0xdfff. And we can now convert a pair to one 5 digit code.
else if(c >= 0xdc00 && c <= 0xdfff) {
low = c;
long unicode = (((long)high - 0xd800) * 0x400) + ((long)low - 0xdc00) + 0x10000;
}
All other symbols are not pairs so process them as is.
else {
long unicode = c;
}
Now use data from emoji-data.txt to check if it's emoji.
If it is, then skip it. If not then copy bytes to output byte array.
Finally byte array is converted to String by
String out = new String(outarray, Charset.forName("UTF-16BE"));

For those using Kotlin, Char.isSurrogate can help as well. Find and remove the indexes that are true from that.

Here is what I use to remove emojis. Note: This only works on API 24 and forwards
public String remove_Emojis_For_Devices_API_24_Onwards(String name)
{
// we will store all the non emoji characters in this array list
ArrayList<Character> nonEmoji = new ArrayList<>();
// this is where we will store the reasembled name
String newName = "";
//Character.UnicodeScript.of () was not added till API 24 so this is a 24 up solution
if (Build.VERSION.SDK_INT > 23) {
/* we are going to cycle through the word checking each character
to find its unicode script to compare it against known alphabets*/
for (int i = 0; i < name.length(); i++) {
// currently emojis don't have a devoted unicode script so they return UNKNOWN
if (!(Character.UnicodeScript.of(name.charAt(i)) + "").equals("UNKNOWN")) {
nonEmoji.add(name.charAt(i));//its not an emoji so we add it
}
}
// we then cycle through rebuilding the string
for (int i = 0; i < nonEmoji.size(); i++) {
newName += nonEmoji.get(i);
}
}
return newName;
}
so if we pass in a string:
remove_Emojis_For_Devices_API_24_Onwards("😊 test 😊 Indic:ढ Japanese:な 😊 Korean:ㅂ");
it returns: test Indic:ढ Japanese:な Korean:ㅂ
Emoji placement or count doesn't matter

Converting sections of byte arrays to integer values

I am currently making an android application which accepts bluetooth measurement from a device. The way the data is packaged is in 4 bytes. I need to get two values out of these bytes.
First value is made up of: 6bit and 7bit of first byte and bit 0 to bit 6 of byte 2
Second values is simpler and consists of the full 3rd byte.
What is a good way to access these bit values, combine them and convert them to integer values? Right now i'm trying to convert from byte array to bitset, and then access individual bits to create new bytes that would then be converted to a integer.
Thanks, and please ask if I am not being clear enough.

I figured it out: I converted the byte array to int using this method
public static int byteArrayToInt(byte[] b, int offset) {
int value = 0;
for (int i = 0; i < 4; i++) {
int shift = (4 - 1 - i) * 8;
value += (b[i + offset] & 0x000000FF) << shift;
}
return value;
}
Then I used the method pokey described. Thanks for your help!

im not sure if i understood your format correctly.
Does this bitmask correspond to your first value?
0xC07F0000
That is bits 16-22,30,31 (zero based indexing used here, i.e. bit 31 is last bit).
Another thing, is your value expected to be signed or unsigned?
Anyway, if it is the way i assume then you can convert it like this with some bitmasks:
unsigned int val = 0xdeadbeef;
unsigned int mask1 = 0xC0000000;
unsigned int mask2 = 0x007F0000;
unsigned int YourValue = (val&mask1)>>23 | (val&mask2)>>16;
Do that in the same way with your other values. Define a bitmask and shift it to the right. Done.
Cheers