Develop Reference

How to limited EditText for start characters just english alphabet in Android

In my application I want use EditText and I want start characters just English alphabet.
My mean is, First of characters has just English alphabet (a to z).
I write below codes :
registerUsernameEdtTxt.addTextChangedListener(new TextWatcher() {
#Override
public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {
if (charSequence.toString().length() < 2) {
registerUsernameEdtTxt.setFilters(new InputFilter[]{new InputFilter() {
public CharSequence filter(CharSequence src, int start,
int end, Spanned dst, int dstart, int dend) {
if (src.toString().matches("[a-zA-Z ]+")) {
registerUsernameInptLay.setErrorEnabled(false);
return src;
}
registerUsernameInptLay.setError(context.getResources().getString(R.string.insertJustEnglish));
return "";
}
}});
}
}
#Override
public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
}
#Override
public void afterTextChanged(Editable editable) {
}
});
But not work me! How can I it?
Please help me

Try this:
EditText et = findViewById(R.id.text_field);
// This part is to keep the existing filters of the EditText.
InputFilter[] filters = et.getFilters();
InputFilter[] newFilters = Arrays.copyOf(filters, filters.length + 1);
InputFilter firstFilter = new InputFilter() {
#Override
public CharSequence filter(CharSequence source, int start, int end, Spanned dest, int dstart, int dend) {
if (source != null && source.length() > 0 && dstart == 0){
if (!source.toString().matches("^[A-Za-z].*"))
return "";
}
return null;
}
};
// Add the filter to the array of filters
newFilters[newFilters.length - 1] = firstFilter;
et.setFilters(newFilters);
Can be simplified like this (if the previous InputFilter are not required)
EditText et = findViewById(R.id.text_field);
InputFilter firstFilter = new InputFilter() {
#Override
public CharSequence filter(CharSequence source, int start, int end, Spanned dest, int dstart, int dend) {
if (source != null && source.length() > 0 && dstart == 0){
if (!source.toString().matches("^[A-Za-z].*"))
return "";
}
return null;
}
};
et.setFilters(new InputFilter[]{firstFilter});
EDIT
If you want to keep the rest of the string (for example if the user pastes the text):
#Override
public CharSequence filter(CharSequence source, int start, int end, Spanned dest, int dstart, int dend) {
if (source != null && source.length() > 0 && dstart == 0) {
String s = source.toString();
if (!s.matches("^[A-Za-z].*")) {
Toast.makeText(getApplicationContext(), "This is a Toast", Toast.LENGTH_SHORT).show();
return s.substring(1, s.length());
}
}
return null;
}
EDIT 2
The above versions don't work on deletion or when a text is pasted with more than a forbidden char at the beginning (e.g. '88sdfs') as only the first one was removed and the rest kept.
This new version should cover all these cases.
I'd suggest to create a separated class for the InputFilter.
InputFilter firstFilter = new InputFilter() {
#Override
public CharSequence filter(CharSequence source, int start, int end, Spanned dest, int dstart, int dend) {
if (dstart != 0) { // The modified part is not beginning of the text
return null; // Nothing need to be changed
}
if (source.length() > 0) { // text is added
return onTextAdded(source.toString());
} else { // text is removed
return onTextRemoved(dest, dend);
}
}
private CharSequence onTextRemoved(Spanned dest, int dend) {
// check what the string will look like after the text being removed
String substring = dest.toString().substring(dend, dest.length());
// if there is still a string and it's not valid
if (substring.length() > 0 && !isValid(substring)) {
displayError();
// return the deleted part for the string to not change
return dest.subSequence(0, dend);
}
return null;
}
private String onTextAdded(String s) {
if (isValid(s)) {
return null;
} else {
String substring;
// We want to keep a part of the added string (it can be a paste).
// so we remove all the first characters as long as the string doesn't match
// the requirements
for (int i = 1; i < s.length(); i++) {
substring = s.substring(i, s.length());
if (isValid(substring))
break;
}
displayError();
return substring;
}
}
private boolean isValid(String s) {
return s.matches("^[A-Za-z].*");
}
private void displayError() {
Toast.makeText(getApplicationContext(), "This is a Toast", Toast.LENGTH_SHORT).show();
}
};
et.setFilters(new InputFilter[]{firstFilter});

Add this class to your project:
public class EnglishInputFilter implements InputFilter {
#Override
public CharSequence filter(CharSequence charSequence, int start, int end, Spanned spanned, int dstart, int dend) {
StringBuilder newChars = new StringBuilder(charSequence.toString().substring(start, end));
for (int i = 0; i < newChars.length(); ) {
if (!Character.isLetter(newChars.charAt(i)))
newChars.deleteCharAt(i);
else
i++;
}
return newChars.toString();
}
}
Then do this with your EditText:
myEditText.setInputType(InputType.TYPE_TEXT_FLAG_NO_SUGGESTIONS)
myEditText.setFilters(new InputFilter[]{new EnglishInputFilter()});
It also removes no letter characters from pasted strings, if you paste "1A2B" it will really paste "AB"
You can add more filters, for example for limit the total length.

If you want that your edit text should accept starting first character with any English alphabet Then you can use regular expression like;
String regexp = "^([a-zA-Z]+).*$";
Pattern pattern = Pattern.compile(regexp);
boolean ismatches = pattern.matcher("your input that start with the alphabet").matches();
if(ismatches)
do your stuff
else
show error

how to avoid characters like �‎ in an edittext?

I have an issue when user try to enter text copied that this text sometimes contains some special characters like �
and this make JSON string to be not formated, so please how can I avoid user enter such characters
please take into consideration that user can enter Arabic text and English text only

Try using InputFilters on the Edittext:
InputFilter filter = new InputFilter() {
#Override
public CharSequence filter(CharSequence source, int start, int end,
Spanned dest, int dstart, int dend) {
StringBuilder stringBuilder = new StringBuilder();
for (int i = start; i < end; i++) {
if (isEnglishOrArabicChar(source.charAt(i))) {
stringBuilder.append(source.charAt(i));
}
}
return stringBuilder.toString();
}
};
etName.setFilters(new InputFilter[]{filter});
private static boolean isEnglishOrArabicChar(char c) {
Character.UnicodeBlock ub = Character.UnicodeBlock.of(c);
return ub == Character.UnicodeBlock.ARABIC || ub==Character.UnicodeBlock.BASIC_LATIN;
}
Reference

android- restrict edittext to accept farsi characters only

I want to restrict my edittext to only accept farsi charecters . charecters like ض ص ث ق ف And so on .
I've tried to use xml digit but it did not work .
how can I do so ?

You can use InputFilter for the EditText. InputFilters can be attached to Editables to constrain the changes that can be made to them.
InputFilter filter = new InputFilter() {
public CharSequence filter(CharSequence source, int start, int end,
Spanned dest, int dstart, int dend) {
for (int i = start; i < end; i++) {
String text = String.valueOf(source.charAt(i));
Pattern RTL_CHARACTERS = Pattern.compile("[\u0600-
\u06FF\u0750-\u077F\u0590-\u05FF\uFE70-\uFEFF]");
Matcher matcher = RTL_CHARACTERS.matcher(text);
if (matcher.find()) {
return ""; // it's Persian
}
}
return null;
}
};
Use this filter to detect Farsi/Persian characters and restrict them for edittext. Set this filter to your EditText using
editText.setFilters(new InputFilter[]{filter});
This will restrict Farsi/Persian characters

These code can help too:
InputFilter nameFilter = new InputFilter() {
#Override
public CharSequence filter(CharSequence source, int start, int end, Spanned dest, int dstart, int dend) {
for (int i = start; i < end; i++) {
if (Character.isLetterOrDigit(source.charAt(i))) { // if digit!
String blockCharacterSet = getString(R.string.all_fa_words) + ' ';
if (blockCharacterSet.contains(String.valueOf(source.charAt(i)))) {
edtNameEdit.setHintTextColor(getResources().getColor(R.color.materialWhite));
edtNameEdit.setHint(getString(R.string.name_lastname));
return null;
} else {
edtNameEdit.setHintTextColor(getResources().getColor(R.color.sPink));
edtNameEdit.setHint(getString(R.string.name_lastname) + ' ' + getString(R.string.must_fa));
return edtNameEdit.getText().toString();
}
} else {
return null;
}
}
return null;
}
};
edtNameEdit.setFilters(new InputFilter[]{nameFilter});
edtNameEdit.setInputType(InputType.TYPE_TEXT_FLAG_NO_SUGGESTIONS);

Android EditText Space Validation

I have an Edittext in my android application. I don't want to allow user to enter first space character..but after entering other charecter user can enter space also..I used
<EditText
android:id="#+id/editText1_in_row"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:inputType="text"
android:digits="_,qwertzuiopasdfghjklyxcvbnm,QWERTYUIOPASDFGHJKLZXCVBNM,0123456789">
but in this case user can not enter space.
I have also used Text Watcher but I need not to allow user at the time of entering text as
android:digits works.

final EditText editText = (EditText)findViewById(R.id.editText1_in_row);
InputFilter filter = new InputFilter() {
boolean canEnterSpace = false;
public CharSequence filter(CharSequence source, int start, int end,
Spanned dest, int dstart, int dend) {
if(editText.getText().toString().equals(""))
{
canEnterSpace = false;
}
StringBuilder builder = new StringBuilder();
for (int i = start; i < end; i++) {
char currentChar = source.charAt(i);
if (Character.isLetterOrDigit(currentChar) || currentChar == '_') {
builder.append(currentChar);
canEnterSpace = true;
}
if(Character.isWhitespace(currentChar) && canEnterSpace) {
builder.append(currentChar);
}
}
return builder.toString();
}
};
editText.setFilters(new InputFilter[]{filter});
and remove this property from your EditText
android:digits="_,qwertzuiopasdfghjklyxcvbnm,QWERTYUIOPASDFGHJKLZXCVBNM,0123456789"
This code works exactly according to your needs.

Using InputFilter easy to handle enter first white space character ignore
First setFilters() method on editText
editText.setFilters(new InputFilter[]{ignoreFirstWhiteSpace()});
Make InputFilter
// ignore enter First space on edittext
public InputFilter ignoreFirstWhiteSpace() {
return new InputFilter() {
public CharSequence filter(CharSequence source, int start, int end,
Spanned dest, int dstart, int dend) {
for (int i = start; i < end; i++) {
if (Character.isWhitespace(source.charAt(i))) {
if (dstart == 0)
return "";
}
}
return null;
}
};
}
No need to write android:digits property on XML
remove this line
android:digits="_,qwertzuiopasdfghjklyxcvbnm,QWERTYUIOPASDFGHJKLZXCVBNM,0123456789"

Simply restrict the user to type space as others said on start only:
#Override
public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
String text = createPL.getText().toString();
//restrict space for first char
if (text.startsWith(" ")) {
edittext.setText(text.trim());
}
}

Use this. If the character at starting Position is a space, set textView Text To blank
editText1_in_row.addTextChangedListener(new TextWatcher() {
#Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
if (s.length()>0 && s.subSequence(0, 1).toString().equalsIgnoreCase(" ")) {
editText1_in_row.setText(""); }
}
#Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
// TODO Auto-generated method stub
}
#Override
public void afterTextChanged(Editable s) {
// TODO Auto-generated method stub
}
});

This works for me
android:inputType="textPersonName"
android:digits= "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890_-!##$%^*()"

why cant you use editText.getText().trim(); function while using the EditText data

If you want to filter input characters in your EditText, you need to use InputFilter. Here is example.
//Allow only letters or digits
InputFilter filter = new InputFilter() {
public CharSequence filter(CharSequence source, int start, int end,
Spanned dest, int dstart, int dend) {
for (int i = start; i < end; i++) {
if (!Character.isLetterOrDigit(source.charAt(i))) {
return "";
}
}
return null;
}
};
EditText text = (EditText)findViewById(R.id.edittext1);
text.setFilters(new InputFilter[]{filter});
For details look here

A slight variation on https://stackoverflow.com/users/2868352/abhishek-v answer.
public class NoInitialSpaceFilter implements InputFilter {
#Override
public CharSequence filter(final CharSequence source, final int start, final int end, final Spanned dest, final int dstart, final int dend) {
if (dstart == 0) {
for (int i = start; i < end; i++) {
if (Character.isSpaceChar(source.charAt(i))) {
return "";
}
}
}
return null;
}
}
Usage:
editText.setFilters(new InputFilter[]{new NoInitialSpaceFilter});

android:digits="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890.,_-!##$()+=><:;?"

This is filter I have used for Name validation in EditText. First letter CAPS, not space and special character. After completing the word not allow more than a single space.
public void setNameFilter() {
InputFilter filter = new InputFilter() {
#RequiresApi(api = Build.VERSION_CODES.KITKAT)
public CharSequence filter(CharSequence source, int start, int end,
Spanned dest, int dstart, int dend) {
for (int i = start; i < end; i++) {
if (dend == 0) {
if (Character.isSpaceChar(source.charAt(i)) ||
!Character.isAlphabetic(source.charAt(i))) {
return Constants.Delimiter.BLANK;
} else {
return String.valueOf(source.charAt(i)).toUpperCase();
}
} else if (Character.isSpaceChar(source.charAt(i)) &&
String.valueOf(dest).endsWith(Constants.Delimiter.ONE_SPACE)) {
return Constants.Delimiter.BLANK;
} else if ((!Character.isSpaceChar(source.charAt(i)) &&
!Character.isAlphabetic(source.charAt(i)))) {
return Constants.Delimiter.BLANK;
}
}
return null;
}
};
editText.setFilters(new InputFilter[]{filter, new InputFilter.LengthFilter(Constants.Length.NAME_LENGTH)});
}

here is kotlin extension
// ignore enter First space on edittext
fun EditText.filterFirstSpace() {
val initSpaceFilter: InputFilter = object : InputFilter {
var canEnterSpace = false
override fun filter(
source: CharSequence, start: Int, end: Int,
dest: Spanned, dstart: Int, dend: Int,
): CharSequence {
if (this#filterFirstSpace.text.toString() == "") {
canEnterSpace = false
}
val builder = StringBuilder()
for (i in start until end) {
val currentChar = source[i]
if (Character.isLetterOrDigit(currentChar) || currentChar == '_') {
builder.append(currentChar)
canEnterSpace = true
}
if (Character.isWhitespace(currentChar) && canEnterSpace) {
builder.append(currentChar)
}
}
return builder.toString()
}
}
filters = arrayOf(initSpaceFilter)
}

How to exclude special characters from android keypad for EditText

Hi I want to show only numbers and characters on the keypad for EditText in android, I did try to add the attribute android:inputType = text|number but it did not work.
Please help me with any other better suggestion. thanks in advance.

Use the filter for that. Here I am adding the code for filter.
EditText etName = (EditText)findViewById(R.id.etName);
InputFilter filter = new InputFilter() {
#Override
public CharSequence filter(CharSequence source, int start, int end, Spanned dest, int dstart, int dend) {
for (int i = start; i < end; i++) {
if (!Character.isLetterOrDigit(source.charAt(i))) {
return "";
}
}
return null;
}
};
etName.setFilters(new InputFilter[]{filter});

try to add the digits parameter to your editText:
android:digits="abcde.....012345789"

The solution with InputFilter provided here is not 100% correct as it will replace and throw out some valid characters from the input if they are right next to the invalid one.
For example we need to filter out all special characters and you enter text: olala[
The EditText field will pass the whole olala[ sentence to the filter and the return value will be "" meaning that we throw out valid olala as well.
Here is my solution:
InputFilter filter = (source, start, end, dest, dstart, dend)->{
for (int i = start; i < end; i++) {
char symbol = source.charAt(i);
if (!isValidCharacter(symbol)) {
StringBuilder buf = new StringBuilder();
for(int j = start; j < end; j++)
{
symbol = source.charAt(j);
if(isValidCharacter(symbol)) buf.append(symbol);
}
return buf.toString();
}
}
return null;
};
We need double loop here to avoid memory allocation of StringBuilder for every method call with valid characters.

If you want to add spaces you can give space after the last digit.
android:digits="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890 "

try using this method it worked for me:
public static InputFilter[] getFilter(String blockChars) {
return new InputFilter[]{(source, start, end, dest, dstart, dend) -> {
for (int i = start; i < end; i++) {
if (source != null && blockChars.contains("" + source.charAt(i))) {
return source.subSequence(start, i);
}
}
return null;
}};
add this line for your edit text
edittext.setFilters(getFilter("#~"));

The expected solution is to restrict user from entering special characters from keyboard.
The below solution uses RegX but adds it to strings.xml file so that will be taken care at the time of creating multilingual xmls.
Strings.xml
<string name="alpha_numeric_regx">[a-zA-Z 0-9]+</string>
Source file
//Extracting forehand to avoid multiple calls to getString from Filter
String alphaNumericRegX = getString(R.string.alpha_numeric_regx);
mEditTextOtp.setFilters(new InputFilter[]{(source, start, end, dest, dStart, dEnd) -> {
for (int i = 0; i < source.length(); i++) {
if (source.equals("")) {
return source;
}
if (source.toString().matches(alphaNumericRegX)) {
return source;
}
return "";
}
return null;
}});
Hope this will solve the prob. for new guys. :)

Kotlin
et_search.keyListener = DigitsKeyListener.getInstance(getString(R.string.alphanumeric))
String.xml
<string name="alphanumeric">0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ</string>

//大兄弟，这么做就可以了。
InputFilter filter = new InputFilter() {
#Override
public CharSequence filter(CharSequence source, int start, int end,
Spanned dest, int dstart, int dend) {
for (int i = start; i < end; i++) {
if (isChineseChar(source.charAt(i))) {
return "";
}
}
return null;
}
};
etName.setFilters(new InputFilter[]{filter});
//一条简单的规则。
private static boolean isChineseChar(char c) {
Character.UnicodeBlock ub = Character.UnicodeBlock.of(c);
return ub == Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS;
}

Its Working
Restrict Special Symbol in Edittext
private EditText your_editText ;
private String blockCharacters = "(~*#^|$%&!";
private InputFilter filter = new InputFilter() {
#Override
public CharSequence filter(CharSequence source, int start, int end, Spanned dest, int dstart, int dend) {
if (source != null && blockCharacters.contains(("" + source))) {
return "";
}
return null;
}
};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
your_editText = (EditText) findViewById(R.id.your_editText);
your_editText .setFilters(new InputFilter[] { filter });
}
}

I couldn't edit a previous answer, so I did a Kotlin version of it (including whitespace):
private val userNameFilter =
InputFilter { source, start, end, dest, dStart, dEnd ->
for (i in start until end) {
if (!Character.isLetterOrDigit(source[i]) && !Character.isWhitespace(source[i])) {
return#InputFilter ""
}
}
null
}