i am new to flutter, in learning phase. in process of creating a simple flutter app which calculate the value of text/number entered in textformfield to single digit number by assigning A=1 to Z=26
Ex: if input is Hello then output should be 7 if input is hello 2 then output should be 9
i tried below code, but
- it is not calculating to single digit,
- it is not calculating for numbers,
- when text box is empty and if i click calculate button, it is displaying old value which is calculated
class _ValueCalculatorState extends State<ValueCalculator> {
final TextEditingController _inputText = TextEditingController();
final TextEditingController _resultsText = TextEditingController();
String results = "0";
String value = "";
String inputText = "";
void clearTextField() {
_inputText.clear();
_resultsText.clear();
setState(() {});
}
@override
Widget build(BuildContext context) {
return GestureDetector(
onTap: () => FocusManager.instance.primaryFocus?.unfocus(),
child: Scaffold(
body: SingleChildScrollView(
child: SafeArea(
child: Padding(
padding: const EdgeInsets.all(10.0),
child: Column(
children: [
TextFormField(
controller: _inputText,
minLines: 5,
maxLines: 9,
keyboardType: TextInputType.multiline,
onChanged: (name) {
inputText = name;
//value1 = name;
},
decoration: InputDecoration(
labelText: 'Enter Text ',
border: OutlineInputBorder(
borderRadius: BorderRadius.circular(10.0),
),
),
),
const Padding(
padding: EdgeInsets.symmetric(
vertical: 20.0,
horizontal: 20.0,
),
),
Text(
results,
style: TextStyle(fontSize: 50),
),
const Padding(
padding: EdgeInsets.symmetric(
vertical: 20.0,
horizontal: 20.0,
),
),
ElevatedButton(
onPressed: () {
// calculation logic\
value = inputText.replaceAll(RegExp('[^A-Za-z0-9]'), '');
int sum = 0;
if (value.trim().isNotEmpty) {
for (int i = 0; i < value.length; i )
(value[i].toUpperCase() == value[i])
? sum = (value.codeUnitAt(i) - 64)
: sum = (value.codeUnitAt(i) - 96);
setState(() {
results = sum.toString();
});
}
print(sum);
},
style: ElevatedButton.styleFrom(
padding: const EdgeInsets.symmetric(
vertical: 25,
horizontal: 60,
),
),
child: const Text("Calculate"),
),
const Padding(
padding: EdgeInsets.symmetric(
vertical: 20.0,
horizontal: 20.0,
),
),
ElevatedButton(
onPressed: () {
clearTextField();
results = "0";
},
child: Text("Reset"),
style: ElevatedButton.styleFrom(
padding: const EdgeInsets.symmetric(
vertical: 15,
horizontal: 30,
),
),
),
],
),
),
),
),
),
);
CodePudding user response：
I hope you will find this helpful
class ValueCalculator extends StatefulWidget {
const ValueCalculator({super.key});
@override
State<StatefulWidget> createState() => _ValueCalculatorState();
}
class _ValueCalculatorState extends State<ValueCalculator> {
final TextEditingController _inputText = TextEditingController();
final Map<int, int> map = {};
String results = "0";
String inputText = "";
_ValueCalculatorState() {
for (var i = 1, j = 'a'.codeUnits.first;
j <= 'z'.codeUnits.first;
i , j ) {
map[j] = i;
}
for (var i = 0, j = '0'.codeUnits.first;
j <= '9'.codeUnits.first;
i , j ) {
map[j] = i;
}
}
@override
void initState() {
super.initState();
_inputText.addListener(_onInputTextChanged);
}
void _onInputTextChanged() => inputText = _inputText.text;
void _clearTextField() {
_inputText.clear();
setState(() {});
}
int _calculate(String input) {
int result = 0;
for (var i = 0; i < input.codeUnits.length; i ) {
final key = input.codeUnitAt(i);
final value = map[key];
if (value != null) {
result = value;
}
}
while (result > 9) {
int sumOfDigits = 0;
for (int i = result; i > 0; i ~/= 10) {
sumOfDigits = i.remainder(10);
}
result = sumOfDigits;
}
return result;
}
@override
Widget build(BuildContext context) {
return GestureDetector(
onTap: () => FocusManager.instance.primaryFocus?.unfocus(),
child: Scaffold(
body: SingleChildScrollView(
child: SafeArea(
child: Padding(
padding: const EdgeInsets.all(10.0),
child: Column(
children: [
TextFormField(
controller: _inputText,
minLines: 5,
maxLines: 9,
keyboardType: TextInputType.multiline,
decoration: InputDecoration(
labelText: 'Enter Text ',
border: OutlineInputBorder(
borderRadius: BorderRadius.circular(10.0),
),
),
),
const Padding(
padding: EdgeInsets.symmetric(
vertical: 20.0,
horizontal: 20.0,
),
),
Text(
results,
style: const TextStyle(fontSize: 50),
),
const Padding(
padding: EdgeInsets.symmetric(
vertical: 20.0,
horizontal: 20.0,
),
),
ElevatedButton(
onPressed: () {
setState(() {
results =
_calculate(inputText.toLowerCase()).toString();
});
},
style: ElevatedButton.styleFrom(
padding: const EdgeInsets.symmetric(
vertical: 25,
horizontal: 60,
),
),
child: const Text("Calculate"),
),
const Padding(
padding: EdgeInsets.symmetric(
vertical: 20.0,
horizontal: 20.0,
),
),
ElevatedButton(
onPressed: () {
results = "0";
_clearTextField();
},
style: ElevatedButton.styleFrom(
padding: const EdgeInsets.symmetric(
vertical: 15,
horizontal: 30,
),
),
child: const Text("Reset"),
),
],
),
),
),
),
),
);
}
@override
void dispose() {
_inputText.removeListener(_onInputTextChanged);
_inputText.dispose();
super.dispose();
}
}
CodePudding user response：
Update your onPressed() method of calculate button as below: it will solve both issues, consider number and for empty string show 0
onPressed: () {
// calculation logic
value = inputText.replaceAll(RegExp('[^A-Za-z0-9]'), '');
int sum = 0;
if (value.trim().isNotEmpty) {
for (int i = 0; i < value.length; i ) {
if (_isNumeric(value[i]) == true) {
sum = int.parse(value[i]);
} else {
(value[i].toUpperCase() == value[i])
? sum = (value.codeUnitAt(i) - 64)
: sum = (value.codeUnitAt(i) - 96);
}
}
}
setState(() {
results = sum.toString() != "" ? sum.toString() : "0";
});
}
//isNumeric func
bool _isNumeric(String result) {
return int.tryParse(result) != null;
}