Simple question that I'm not finding an answer to--I have a TextField that's multi-line but I don't want to allow newlines in the text. E.g., if the user is typing and hits [Enter], I don't want a newline to register in the TextField. How do I do that?
I tried catching it in the onChanged event, but got weird rendering results:
onChanged: (value) {
if (value.endsWith('\n')) {
_textController.text = value.trim();
}
},
You should try using BlacklistingTextInputFormatter in inputFormatters.
inputFormatters: [
FilteringTextInputFormatter.deny(new RegExp(r"\n"))
],
What if you use following parameters:
TextField(keyboardType: TextInputType.text, maxLines: 3,);
Related
Currently, I'm looking at a TextFormField restriction.
My requirement is
Allow single 0 in TextFormField
If it is 099, I want to remove the leading 0. So, it's 99
Do not allow symbols or special characters like "?" or "."
I have tried the below code, but it's still allowed to input "?" or "."
inputFormatters: [
new FilteringTextInputFormatter.allow(new RegExp("[0-9.]")),
new FilteringTextInputFormatter.deny(RegExp(r'^0+(?=.)')),
],
I am seeking your help on this.
Thanks in advance!
you can create a text controller at first :
TextEditingController textEditingController = TextEditingController();
then you can apply this text field :
TextFormField(
keyboardType: TextInputType.number,
controller: textEditingController,
onChanged: (val){
if(val.characters.characterAt(0) == Characters("0") && val.length > 1){
// we need to remove the first char
textEditingController.text = val.substring(1);
// we need to move the cursor
textEditingController.selection = TextSelection.collapsed(offset: textEditingController.text.length);
}
},
)
like this you will be able to enter a single zero but you will not be able write 099 it will be converted automatically to 99 .
Try below code:
TextFormField(
keyboardType: TextInputType.phone,
inputFormatters: [
FilteringTextInputFormatter.deny(
RegExp(r'^0+'),
),
],
),
While the inputFormatters is realy well explained here and works like a charm I want to let the user know about what happened to his input.
A simple snackBar or other dialog should be shown that prompts the user: "Your code has been trimmed because of unallowed signs. You are only allowed to enter numbers and letters!"
my example code shows the limitation to numbers and letters:
TextFormField( inputFormatters: <TextInputFormatter>[ FilteringTextInputFormatter.allow( RegExp("[0-9a-zA-Z]"), ), ],
If the user paste a string that contains other signs they will be deleted automaticly but the user might not see that so I want to show a warning to him.
I appriciate all help.
Thanks for your answeres but I solved it on my own as follows:
The inputFormatter blocks all unallowed signs and won't show them in onChanged value of the textController but the onChanged function is triggered and stays even. So I added the following code to the onChanged: function:
onChanged: (val) {
if (count == val.length) {
showSnackBar(
context,
'You entered an unallowed sign!',
icon: Icons.warning_outlined, // this is from my own class showSnackBar which shows a Row with an optional Icon
);
}
count = val.length;
Everytime the user types an unallowed sign this warning pops up because the textcontroller changed but the value of it stays the same.
If there are parts I can do better please comment and I'll correct them.
The complete Code of the TextFormField including the inputFormatters:
First i created a variabel int count = 0;
TextFormField(
inputFormatters: <TextInputFormatter>[
FilteringTextInputFormatter.allow(
RegExp("[0-9a-zA-Z]"),
),
],
obscureText: false,
controller: _controller,
decoration: InputDecoration(
labelText:
'title',
),
onChanged: (val) {
if (count == val.length) {
showSnackBar(
context,
'Unallowd sign typed in!',
icon: Icons.warning_outlined,
);
}
model.textChanged(val);
count = val.length;
},
),
Thanks
I've got Text field which updateds a value variable to double format in onChange... I want the TextField only display the updated the value variable.. I don't want the textfield to display any string value or values which are not in double format by pressing wrong keyboard key. Even with numeric keyboard with decimal enabled we can press decimal key multiple times which I don't want to display in the TextField.
TextFormField(
decoration: InputDecoration(labelText: 'Value'),
onChanged: (s) {
if (double.tryParse(s) != null)
setState(() {
value = double.parse(s);
});
},
)
How can I display only parsed value in TextField?
Please add below attribute to TextFormField Widget
TextFormField(
keyboardType:TextInputType.numberWithOptions(decimal: true),
inputFormatters: <TextInputFormatter>[
FilteringTextInputFormatter.allow(RegExp(r'^(\d+)?\.?\d{0,2}'))
],
);
#user8773560 was correct however RegExp for decimal number was wrong and not working so the correct answer is
inputFormatters: [
WhitelistingTextInputFormatter(RegExp(r'(^\d*\.?\d*)'))
]
Also answered in my other question Regex for double numbers in dart
Answer based on #delmin's answer, but allows negative numbers as well.
inputFormatters: [
FilteringTextInputFormatter.allow(RegExp(r'(^-?\d*\.?\d*)'))
]
Hello you can not use onChange for this purpose because its called only once TextField has changed.
You should try this.
TextFormField(
inputFormatters: <TextInputFormatter>[
LengthLimitingTextInputFormatter(12), //max length of 12 characters
WhitelistingTextInputFormatter.digitsOnly,//Only numbers
BlacklistingTextInputFormatter.singleLineFormatter,//No line break
WhitelistingTextInputFormatter(RegExp("[0-9]+.[0-9]")) //only double values
],
)
Lear more here or Official doc
I need a numberInputKeyboard which only has numbers (without decimal symbol). I have tried with keyboardType: TextInputType.numberWithOptions(decimal: false) but still this dosen't help me
One answer recommends using a BlacklistingTextInputFormatter which certainly works in your case with English locale. This however might not work with other locales which use a , instead of a . as decimal seperator.
So I'd recommend using a WhitelistingTextInputFormatter:
import "package:flutter/services.dart";
TextFormField(
keyboardType: TextInputType.number,
inputFormatters: [WhitelistingTextInputFormatter.digitsOnly],
)
This will only allows the digits [0-9].
UPDATE:
The WhitelistingTextInputFormatter as been renamed! The following is the up-to date version and no longer deprecated by FilteringTextInputFormatter.allow and provides a shortcut for the digits as well:
import "package:flutter/services.dart";
TextFormField(
keyboardType: TextInputType.number,
inputFormatters: [FilteringTextInputFormatter.digitsOnly],
)
BlacklistingTextInputFormatter and WhitelistingTextInputFormatter are deprecated. If you want to admit digits only, you could use:
FilteringTextInputFormatter.digitsOnly
If you want to admit numbers with decimal point:
FilteringTextInputFormatter.allow(RegExp(r'^(\d+)?\.?\d{0,2}')
First Approach :-
As per this stackoverflow answer you must have to create your custom keyboard for it.
Android - is it possible to hide certain characters from the soft keyboard?
Second Approach :-
You can do black list that stuff with RegExp, in this case you can't input dot(.).
For more you can refer this : https://api.flutter.dev/flutter/services/TextInputFormatter-class.html
body: Center(
child: TextFormField(
decoration: InputDecoration(
labelText: "Title",
suffixIcon: GestureDetector(
onTap: () {
setState(() {
});
},
child: Icon(Icons.clear),
)),
inputFormatters: [
FilteringTextInputFormatter.deny(RegExp("[.]")),
],
)));
To aport this thread i did this, helped with the link provided by Amit Prajapati, its a but more manual but in my case worked perfectly
inputFormatters: [
TextInputFormatter.withFunction((oldValue, newValue) {
if (textInputType.decimal == true) {
return newValue.copyWith(
text: newValue.text.replaceAll(RegExp(r"\,"), "."),
);
}
return newValue;
}),
],
EDIT: textInputType is a variable for a custom TextField
I have a TextField that will only take numbers as an input.
The Keyboard that appears allows for the input of the the following characters: "-(hyphen) ,(comma) .(period) and space". How can I prevent the user from entering all except the period.
child: new TextField(
controller: _controller,
maxLengthEnforced: true,
keyboardType: TextInputType.number,
maxLength: 4, //9999 upper limit
), //TextField
I've tried to use RegExp to take the _controller text, remove the characters and place it back into to field without any luck.
...//Add Listener to _controller
_controller.addListener(restrictCharacters);
...
//Listener
void restrictCharacters(){
RegExp regexp = new RegExp(
r"^|\-|\,|\ ",
caseSensitive: false,
multiLine: false,);
String text = _controller.text;
String chng = text.replaceaLL(regExp,"");
_controller.text = chng;
}
When applied the cursor moves to beginning and the field keeps the - (hyphen) for example.
In your TextInputField(), use a FilteringTextInputFormatter like this:
TextField(
inputFormatters: <TextInputFormatter>[
FilteringTextInputFormatter.allow(RegExp("[0-9a-zA-Z]")),
], // Only numbers can be entered
),
Each character typed will be allowed only if it matches the RegExp. To include a space, use the regular expression "[0-9a-zA-Z ]" instead. Period means "any character" in regular expressions unless you escape them, like "[0-9\.a-zA-Z]".
.deny can be used in place of .allow to proved a blacklist instead of a whitelist.
WhitelistingTextInputFormatter is deprecated. You should use FilteringTextInputFormatter.allow:
inputFormatters: [ FilteringTextInputFormatter.allow(RegExp("[a-zA-Z]")), ]
or FilteringTextInputFormatter.deny instead of BlacklistingTextInputFormatter
Add a BlacklistingTextInputFormatter to your TextField.
inputFormatters: [
new BlacklistingTextInputFormatter(new RegExp('[\\.]')),
],
removes just . If you wanted to disallow, say, . and , change it to
inputFormatters: [
new BlacklistingTextInputFormatter(new RegExp('[\\.|\\,]')),
],
Add this to your TextField for letters and numbers
inputFormatters: [new WhitelistingTextInputFormatter(RegExp("[a-zA-Z0-9]")),],
If you want double to be added,you can also use the format like this:
inputFormatters: [FilteringTextInputFormatter.allow(RegExp("[0-9\.]")),],
Be sure to include the backslash, as a period on its own means "any character" (allowing everything).
Dart 2.13+, Flutter 1.27+
inputFormatters:[FilteringTextInputFormatter.allow(RegExp('[a-zA-Z0-9]'))]
For those who need to work with money format in the text fields:
To use only: , (comma) and . (period)
and block the symbol: - (hyphen, minus or dash)
as well as the: ⌴ (blank space)
In your TextField, just set the following code:
keyboardType: TextInputType.numberWithOptions(decimal: true),
inputFormatters: [BlacklistingTextInputFormatter(new RegExp('[ -]'))],
The simbols hyphen and space will still appear in the keyboard, but will become blocked.
inputFormatters: <TextInputFormatter>[FilteringTextInputFormatter.allow(RegExp("[0-9a-zA-Z]")),],
if you want to include English and Devanagari character also in your name
then follow this regex pattern
I have created this pattern for English letter and Devanagari letters with allow space
inputFormatters: [ WhitelistingTextInputFormatter(RegExp("[a-zA-Z \u0900-\u097F]")),
LengthLimitingTextInputFormatter(30),
],
You can deny special characters with escape sequences
or get any escape sequence from google which you want
Example:
inputFormatters: [
FilteringTextInputFormatter.deny(
RegExp("[a-zA-Z0-9\u0020-\u007E-\u0024-\u00A9]"),
),
],
None of the above answers worked for me, This is how to use FilteringTextInputFormatter inside TextFormField:
TextFormField(
inputFormatters: [
FilteringTextInputFormatter(
RegExp("[a-zA-Z]"),
allow: true),
],)
Set allow to false if you want to deny the RegExp.
Add this to your TextField for letters and numbers
inputFormatters: [WhitelistingTextInputFormatter(RegExp("[a-zA-Z0-9]")),],