Develop Reference

How to get last 4 digit of number in android?

I have an app which contain mobile number edit text in which user can edit mobile number and I have to send two request to server like:- mobile number and mssdn,mobile number(which is full lenghth ) and mssdn(which contain mobile number last 4 digit).How can I do that

Try this. Check for length greater than 4 before calling subString to avoid IndexOutOfBounds Exception.
EditText mEdtPhoneNumber = (EditText) findViewById(R.id.edtPhoneNumber);
String phoneNumber = mEdtPhoneNumber.getText().toString().trim();
String strLastFourDi = phoneNumber.length() >= 4 ? phoneNumber.substring(phoneNumber.length() - 4): "";
Also what is mssdn?? Is it msisdn??

Use the modulus (%) operator:
To get the last digit: use number % 10
To get the last 2 digits: use number % 100
and so on
For example:
42455%10000 = 2455

You could do something like this:
EditText phoneNumberEditText = (EditText) findViewById(R.id.phoneNumberEditText);
String phoneNumber = phoneNumberEditText.getText().toString();
String lastFourDigits = phoneNumber.substring(phoneNumber.length() - 4);

you should use regex because this will only give you result if the last four letters are actually numbers on the other hand the substring function simply give you last four letters no matter they are numbers or characters. e.g 4344sdsdss4 will give you dss4 which is clearly not a part of phone number
String str="4444ntrjntkr555566";
Pattern p = Pattern.compile("(\\d{4})$");
Matcher m = p.matcher(str);
if (m.find()) {
System.out.println(m.group(m.groupCount()));
}
this will produce 5566
Working
//d mean digits
{4} for fix length as 4
$ mean at the end

List<Integer> f(String str){
ArrayList<Integer> digits = new ArrayList<>();
if (null == str || str.length() < 4){
Log.i(LOG_TAG, "there are less than 4 digits");
return digits;
}
String digitsStr = str.substring(str.length() - 4);
for (char c : digitsStr.toCharArray()){
try {
Integer digit = Integer.parseInt(String.valueOf(c));
digits.add(digit);
} catch (Exception e){
continue;
}
}
return digits;
}

We can also use a new method introduced in kotlin: takeLast(n)
fun getLastDigit(data: String, n:Int): String {
return if(data.length > n){
data.takeLast(n)
}else {
""
}
}

Android app crashes when no value is in edit text

I am making a unit converter, but if I do not enter any value into edit text and press the calculate button the app crashes with error Invalid float: "". Also, I want to forbid zeroes from being entered before numbers (eg. 0300). How do I accomplish this?
//handle calculate
calcButton=(Button)findViewById(R.id.calcButton);
calcButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Spinner spinner = (Spinner) findViewById(R.id.unit_spinner);
String spinnerText = spinner.getSelectedItem().toString();
EditText unit_edit = (EditText) findViewById(R.id.unit_edit);
amount = Float.valueOf(unit_edit.getText().toString());
if (unit_edit.getText().toString().equals(null)) {
Toast.makeText(getApplicationContext(), "Insert Value To Convert",
Toast.LENGTH_LONG).show();
} else {
switch (spinnerText) {
case "Kilograms":
kilograms = amount;
grams = amount * 1000;
ListView();
break;
case "Grams":
grams = amount;
kilograms = amount / 1000;
ListView();
break;
}
}
}
});
}

You are probably getting an NumberFormatException thrown since the EditText fields text is "" and "" is not a valid float value, the exception is thrown at the following line:
amount = Float.valueOf(unit_edit.getText().toString());
What you'll need to do is add some validation and checking before trying to get the float value of a String.
Check the methods documentation for more details http://docs.oracle.com/javase/7/docs/api/java/lang/Double.html#valueOf(java.lang.String)

This might be useful for your EditText to limit input to numbers only.
<EditText
android:id="#+id/unit_edit"
android:inputType="number"
/>
You can also limit the digits, type of number such as decimal
<EditText
android:id="#+id/unit_edit"
android:digits="0123456789."
android:inputType="numberDecimal"
/>

You can't parse an empty value to float. You should first test if it's empty, and then do what you want, something like this:
String text = unit_edit.getText().toString();
if(!text.isEmpty()){ // Test if the text is empty
if(text.matches("[0-9]+")){ // Test if it only contains numbers, using REGEX
amount = Float.valueOf(text); // Only then parse to float.
// Switch and rest of the stuff
} else {
Toast.makeText(getApplicationContext(), "Use only numbers from 0 to 9.",
Toast.LENGTH_LONG).show();
}
} else {
Toast.makeText(getApplicationContext(), "The field is empty",
Toast.LENGTH_LONG).show();
}
The comments explain what's going on. About the leading 0 in some numbers, using "valueOf" will remove it already, and 0300 will be parsed as 300, so there's nothing to worry about.If you still want something related to it, let me know and i'll edit my answer.

Regular Expression In Android for Password Field

How can i validating the EditText with Regex by allowing particular characters .
My condition is :
Password Rule:
One capital letter
One number
One symbol (#,$,%,&,#,) whatever normal symbols that are acceptable.
May I know what is the correct way to achieve my objective?

Try this may helps
^(?=.*[0-9])(?=.*[a-z])(?=.*[A-Z])(?=.*[##$%^&+=])(?=\\S+$).{4,}$
How it works?
^ # start-of-string
(?=.*[0-9]) # a digit must occur at least once
(?=.*[a-z]) # a lower case letter must occur at least once
(?=.*[A-Z]) # an upper case letter must occur at least once
(?=.*[##$%^&+=]) # a special character must occur at least once you can replace with your special characters
(?=\\S+$) # no whitespace allowed in the entire string
.{4,} # anything, at least six places though
$ # end-of-string
How to Implement?
public class MainActivity extends Activity {
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final EditText editText = (EditText) findViewById(R.id.edtText);
Button btnCheck = (Button) findViewById(R.id.btnCheck);
btnCheck.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View arg0) {
if (isValidPassword(editText.getText().toString().trim())) {
Toast.makeText(MainActivity.this, "Valid", Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(MainActivity.this, "InValid", Toast.LENGTH_SHORT).show();
}
}
});
}
public boolean isValidPassword(final String password) {
Pattern pattern;
Matcher matcher;
final String PASSWORD_PATTERN = "^(?=.*[0-9])(?=.*[a-z])(?=.*[A-Z])(?=.*[##$%^&+=])(?=\\S+$).{4,}$";
pattern = Pattern.compile(PASSWORD_PATTERN);
matcher = pattern.matcher(password);
return matcher.matches();
}
}

And for the Kotlin lovers :
fun isValidPassword(password: String?) : Boolean {
password?.let {
val passwordPattern = "^(?=.*[0-9])(?=.*[a-z])(?=.*[A-Z])(?=.*[##$%^&+=])(?=\\S+$).{4,}$"
val passwordMatcher = Regex(passwordPattern)
return passwordMatcher.find(password) != null
} ?: return false
}

None of the above worked for me.
What worked for me:
fun isValidPasswordFormat(password: String): Boolean {
val passwordREGEX = Pattern.compile("^" +
"(?=.*[0-9])" + //at least 1 digit
"(?=.*[a-z])" + //at least 1 lower case letter
"(?=.*[A-Z])" + //at least 1 upper case letter
"(?=.*[a-zA-Z])" + //any letter
"(?=.*[##$%^&+=])" + //at least 1 special character
"(?=\\S+$)" + //no white spaces
".{8,}" + //at least 8 characters
"$");
return passwordREGEX.matcher(password).matches()
}
Source: Coding in Flow
Hope it helps someone.

Try this.
(/^(?=.*\d)(?=.*[A-Z])([#$%&#])[0-9a-zA-Z]{4,}$/)
(/^
(?=.*\d) //should contain at least one digit
(?=.*[#$%&#]) //should contain at least one special char
(?=.*[A-Z]) //should contain at least one upper case
[a-zA-Z0-9]{4,} //should contain at least 8 from the mentioned characters
$/)

try {
if (subjectString.matches("^(?=.*[#$%&#_()=+?»«<>£§€{}\\[\\]-])(?=.*[A-Z])(?=.*[a-z])(?=.*\\d).*(?<=.{4,})$")) {
// String matched entirely
} else {
// Match attempt failed
}
} catch (PatternSyntaxException ex) {
// Syntax error in the regular expression
}
(?=.*[#\$%&#_()=+?»«<>£§€{}.[\]-]) -> must have at least 1 special character
(?=.*[A-Z]) -> Must have at least 1 upper case letter
(?=.*[a-z]) -> Must have at least 1 lower case letter
(?=.*\\d) -> Must have at least 1 digit
(?<=.{4,})$") -> Must be equal or superior to 4 chars.

As an addition to the answers already given, I would suggest a different route for identifying special characters and also would split up the check for the different rules.
First splitting it up: Instead of making one big rule, split it and check every rule separately, so that you are able to provide feedback to the user as to what exactly is wrong with his password. This might take a bit longer but in something like a password checkup this will not be noticable. Also, this way the conditions are more readable.
Secondly, instead of checking for a list of special characters, you could flip it and check if the password contains any characters that are neither letters of the latin alphabet (a-zA-Z) nor digits (0-9). That way you don't "forget" special characters. For example, lets say you check specifically but in your check you forget a character like "{”. With this approach, this can't happen. You can extend that list by things you don't consider to be special characters explicitly, for example a space. In kotlin, it would look like this:
val errorText = when {
/* Rule 1 */
!password.contains(Regex("[A-Z]")) -> "Password must contain one capital letter"
/* Rule 2 */
!password.contains(Regex("[0-9]")) -> "Password must contain one digit"
/* Rule 3, not counting space as special character */
!password.contains(Regex("[^a-zA-Z0-9 ]")) -> "Password must contain one special character"
else -> null
}
Depending on your encoding, you can also use regex and define your special characters using ranges of hex codes like
Reges("[\x00-\x7F]")

I'm too late to answer but still it may help you.
I've worked with Kotlin.
Add following function.
private fun isValidPassword(password: String): Boolean {
val pattern: Pattern
val matcher: Matcher
val specialCharacters = "-#%\\[\\}+'!/#$^?:;,\\(\"\\)~`.*=&\\{>\\]<_"
val PASSWORD_REGEX = "^(?=.*[0-9])(?=.*[a-z])(?=.*[A-Z])(?=.*[$specialCharacters])(?=\\S+$).{8,20}$"
pattern = Pattern.compile(PASSWORD_REGEX)
matcher = pattern.matcher(password)
return matcher.matches()
}
Function description:
(?=.*[0-9]) # a digit must occur at least once
(?=.*[a-z]) # a lower case letter must occur at least once
(?=.*[A-Z]) # an upper case letter must occur at least once
(?=.[-#%[}+'!/#$^?:;,(")~`.=&{>]<_]) # a special character must occur at least once
replace with your special characters
(?=\S+$) # no whitespace allowed in the entire string .{8,} #
anything, at least six places though
You can modify it as needed.
Hope it helps.

you can use the class Patern than Matcher for every checking format.
I give you an exemple of use :
Pattern pattern = Pattern.compile(".+#.+\\.[a-z]+");
Matcher matcher = pattern.matcher(myEmailString);
if (!myEmailString.contains("#") || !matcher.matches()) {
// error in the email : do staff
myEmailView.setError("invalid email !");
}

All of the other answers are good, but the implementation of special characters were a bit too messy for my taste. I used Unicode for special characters instead.
I used special characters specified in the OWASP website.
Kotlin:
val SPECIAL_CHARACTERS_REGEX =
"?=.*[\\u0020-\\u002F\\u003A-\\u0040\\u005B-\\u0060\\u007B-\\u007E]"
val PASSWORD_REGEX =
"^(?=.*[0-9])(?=.*[a-z])(?=.*[A-Z])($SPECIAL_CHARACTERS_REGEX).{8,}\$"
fun isValidPassword(password: String) = Pattern.matches(PASSWORD_REGEX, password)

Most common password validation is
At least 8 character
Require numbers
Require special character
Require uppercase letters
Require lowercase letters
Regex:
^(?=.*[0-9])(?=.*[a-z])(?=.*[A-Z])(?=.*[\\\/%§"&“|`´}{°><:.;#')(#_$"!?*=^-]).{8,}$
Kotlin code:
val PASSWORD_REGEX_PATTERN = "^(?=.*[0-9])(?=.*[a-z])(?=.*[A-Z])(?=.*[\\\/%§"&“|`´}{°><:.;#')(#_$"!?*=^-]).{8,}$"
fun isValidPassword(password: String?): Boolean {
val pattern: Pattern =
Pattern.compile(PASSWORD_REGEX_PATTERN)
val matcher: Matcher = pattern.matcher(password)
return matcher.matches()
}
online regex validator to check it:
https://regex101.com/
https://www.freeformatter.com/java-regex-tester.html#ad-output

private fun passwordValidate(password1: String, password2: String): Boolean {
when {
password1.length < 9 -> {
textView2.text = "Password Has To Be At Least 9 Characters Long"
return false
}
!password1.matches(".*[A-Z].*".toRegex()) -> {
textView2.text = "Password Must Contain 1 Upper-case Character"
return false
}
!password1.matches(".*[a-z].*".toRegex()) -> {
textView2.text = "Password Must Contain 1 Lower-case Character"
return false
}
!password1.matches(".*[!##$%^&*+=/?].*".toRegex()) -> {
textView2.text = "Password Must Contain 1 Symbol"
return false
}
password1 != password2 -> {
textView3.text = "Passwords Don't Match"
return false
}
else -> return true

Try this,
if (validatePassword())
{
// if valid
}
private boolean validatePassword() {
String passwordInput = password.getText().toString().trim();
if (!passwordInput.matches(".*[0-9].*")) {
Toast.makeText(mActivity, "Password should contain at least 1 digit", Toast.LENGTH_SHORT).show();
return false;
}
else if (!passwordInput.matches(".*[a-z].*")) {
Toast.makeText(mActivity, "Password should contain at least 1 lower case letter", Toast.LENGTH_SHORT).show();
return false;
}
else if (!passwordInput.matches(".*[A-Z].*")) {
Toast.makeText(mActivity, "Password should contain at least 1 upper case letter", Toast.LENGTH_SHORT).show();
return false;
}
else if (!passwordInput.matches(".*[a-zA-Z].*")) {
Toast.makeText(mActivity, "Password should contain a letter", Toast.LENGTH_SHORT).show();
return false;
}
else if (!passwordInput.matches( ".{8,}")) {
Toast.makeText(mActivity, "Password should contain 8 characters", Toast.LENGTH_SHORT).show();
return false;
}
else {
return true;
}
}

I have a simple way to check it without using regex in Kotlin.
It will check for password length >= 8, at least one capital letter, one small letter, one number, and one special character.
fun isValidPassword(pass:String):Boolean{
if(pass.length<8) return false
var u = 0
var l = 0
var d = 0
var s = 0
for (char in pass){
if(char.isUpperCase()) u++
else if(char.isLowerCase()) l++
else if(char.isDigit()) d++
else if(char in "##$%^&+=_.") s++
}
if(u==0|| l==0 || s==0 || d==0) return false
return true
}

Regex in android for email,username & mobile number

I want to use regex in my android application to validate some field.
User Name :
1 Capital Letter[A-Z], 2 digit[0-9], 1 Special Character any and then followed by small character[a-z] and lenth would be 10 character max.
Email Address :
Must contain #google.com in last
Mobile :
Must be +91 and after that 10 digit.
How can I form my regex pattern for all three fields..?

Regx for emailid:
^[A-Za-z][A-Za-z0-9]*([._-]?[A-Za-z0-9]+)#[A-Za-z].[A-Za-z]{0,3}?.[A-Za-z]{0,2}$
accepts values as:
hdf4.j8k#bfv.djf
ds.sd#c25v.fdv
dv_sdv#fvv
vdf-f#jn.fdv
jfk#mbf.khb.in
n etc
Regex for Mobile No:
^[7-9][0-9]{9}$
works perfect for indian mobile numbers.
Regex for landline No:
^[0-9]{3,5}-[2-9]{1}[0-9]{5,7}$
for landline numbers in india with region code
eg: 022-58974658

You can find the regex you require for password, email and more , for instance
For Username :
^[a-z0-9_-]{3,15}$
^ # Start of the line
[a-z0-9_-] # Match characters and symbols in the list, a-z, 0-9
, underscore , hyphen
{3,15} # Length at least 3 characters and maximum length of 15
$ # End of the line
at : http://www.mkyong.com/regular-expressions/10-java-regular-expression-examples-you-should-know/

Please see below link for Email Validation and you can modify some part of the code for username validation and phone number validation.
how-to-check-edittexts-text-is-email-address-or-not

public static boolean isEmailValid(String email) {
boolean isValid = false;
String expression = "^[\\w\\.-]+#([\\w\\-]+\\.)+[A-Z]{2,4}$";
CharSequence inputStr = email;
Pattern pattern = Pattern.compile(expression, Pattern.CASE_INSENSITIVE);
Matcher matcher = pattern.matcher(inputStr);
if (matcher.matches()) {
isValid = true;
}
return isValid;
}

Mobile :
Must be +91 and after that 10 digit.
^[7-9][0-9]{9}$ is useful for only mobile numbers. But for country code we should have to use regex like ^[+(00)][0-9]{6,14}$ ..
something like
1)
String phoneNumber = "+919900990000"
if(phoneNumber.matches("^[+(00)][0-9]{6,14}$")){
//True
2)
String phoneNumber = "9900990000"
if(phoneNumber.matches("^[+(00)][0-9]{6,14}$")){
//False
The first is true because it has the country code with it, But the second one is false because it has not any country code attached with it.

You can use Patterns class for validating factors such as email,mobile no etc.
Here's how:
public static boolean isValidEmail(CharSequence target) {
return (!TextUtils.isEmpty(target) && Patterns.EMAIL_ADDRESS.matcher(target).matches());
}
public static boolean isValidMobile(CharSequence target) {
return (!TextUtils.isEmpty(target) && Patterns.PHONE.matcher(target).matches());
}
Hope it'll help you.

how to do form validation in android

I have a registration form which I need to validate before submit. The form has the following fields:name,email, contact number and password. I need the name to have a value, the email to have the correct format,contact number should be numbers at least 10 numbers and the password to be at least 6 characters.

try this
vUsername = etUsername.getText().toString();
vFirstname = etFirstname.getText().toString();
vEmail = etEmail.getText().toString();
vPwd = etPwd.getText().toString();
vCpwd = etCpwd.getText().toString();
if("".equalsIgnoreCase(vUsername) //vUsername.equalsIgnoreCase("") could lead to NPE
|| "".equalsIgnoreCase(vFirstname)
|| "".equalsIgnoreCase(vEmail)
|| "".equalsIgnoreCase(vPwd)
|| "".equalsIgnoreCase(vCpwd) )
{
Toast.makeText(userRegistration.this, "All Fields Required.",
Toast.LENGTH_SHORT).show();
}
checkemail(vEmail);
if(emailcheck==true)
{
// your code here
}
public void checkemail(String email)
{
Pattern pattern = Pattern.compile(".+#.+\\.[a-z]+");
Matcher matcher = pattern.matcher(email);
emailcheck = matcher.matches();
}

Alternatively, you can use a validation library to perform your validations on Android. It is driven by annotation and thereby it reduces a lot of boiler-plate code. Your use case when solved using this app would look like the following:
#Required(order = 1)
#Email(order = 2)
private EditText emailEditText;
#Password(order = 3)
#TextRule(order = 4, minLength = 6, message = "Enter at least 6 characters.")
private EditText passwordEditText;
#ConfirmPassword(order = 5)
private EditText confirmPasswordEditText;
#Checked(order = 6, message = "You must agree to the terms.")
private CheckBox iAgreeCheckBox;
There is a dearth of documentation now but the annotation example on the home page should get you started. You can also read this blog on how to create custom rules in case the stock rules do not fit your needs.
PS: I am the author of this library.

You can use the default Android validation API.
Here is a very simple tutorial: http://blog.donnfelker.com/2011/11/23/android-validation-with-edittext/
The key is to use the setError method on your EditText. It will trigger default validation UI with provided error text.

for validation of edittext, use android:inputtype, android:maxLength.
Apart from this, can use regex for validation of form

You have two possibilities:
listen to changes to the field's content and run validation of that specific field or
listen to the submit-button click and validate the content of all fields on submit.
Else validation is just the same as in every other Java app: just test your constraints.
BTW: your question was already answered on stackoverflow.

try this
if(phone.getText().toString().isEmpty()){
if(phone.lenth <= 10){
}else{ // phone is`t correct }
phone.setError("phone number is empty ");
phone.requestFocus();
return;
}
if(password.getText().toString().isEmpty()){
if(password.lenth <= 6){
}else{ // password is`t correct }
password.setError("password number is empty ");
password.requestFocus();
return;
}