Animated Text in Flutter , dart add curves in text style - android

How to add curves.bounceOut in text animation;
Container(child:Text("hello"));


you can define your own animation and controller and tweak it as you like
one way to do it
add with TickerProviderStateMixin to your class
example :
class homeState extends State<home> with TickerProviderStat
then in your class define :
late AnimationController controller;
late Animation<double> animation
;
after that in the init state of your class you can use
controller = AnimationController(
duration: const Duration(seconds: 20), // duration of the animation you want
vsync: this,
);
animation = CurvedAnimation(parent: controller /* the controller we defined above */ , curve: Curves.bounceOut /* the curve of the animation you want */ );
// use
controller.repeat(); //if you want the animation to loop
then use it with your container
if you want to know more here is the flutter documentation link
hope this helps


You can use animated_text_kit Wavy animation
Example from doc
return DefaultTextStyle(
style: const TextStyle(
fontSize: 20.0,
),
child: AnimatedTextKit(
animatedTexts: [
WavyAnimatedText('Hello World'),
WavyAnimatedText('Look at the waves'),
],
isRepeatingAnimation: true,
onTap: () {
print("Tap Event");
},
),
);
You can find more animation on package


Please Use this code for animation text;
follow this code if it helpfull;
Create Variables
late AnimationController controller;
late Animation<double> animation;
int hrs = 0;
int minute = 0;
int second = 0;
double opacity = 0.1;
int duration = 0;
double hp = 0.0;
double mp = 0.0;
double sp = 0.0;
Create Function and add within initState() function;
timer() async {
DateTime date = DateTime.now();
Future.delayed(const Duration(milliseconds: 1000), () {
setState(() {
duration = 900;
sp = 10;
date = DateTime.now();
second = date.second;
hrs = date.hour;
minute = date.minute;
var inputFormat = DateFormat('HH');
var inputDate = inputFormat.parse(hrs.toString());
var outputFormat = DateFormat('hh');
hrs = int.parse(outputFormat.format(inputDate).toString());
if (second == 0) {
mp = 10;
} else if (minute == 0) {
hp = 10;
}
timer();
});
});
Future.delayed(const Duration(milliseconds: 900), () {
setState(() {
sp = 0;
mp = 0;
hp = 0;
duration = 0;
});
});
}
Create a Widget
Widget animatedText(String text, double animatedPadding) {
return TweenAnimationBuilder(
duration: const Duration(milliseconds: 500),
curve: Curves.bounceIn,
tween: IntTween(begin: 0, end: 1),
builder: (context, int val, child) {
if (val != 1 && opacity < 1.0) {
opacity = opacity + 0.1;
} else if (opacity > 1.0 || opacity == 1.0) {
opacity = 1.0;
}
return Opacity(
opacity: opacity >= 0.0 && opacity <= 1.0 ? opacity : 0,
child: AnimatedPadding(
duration: Duration(milliseconds: duration),
curve: Curves.bounceOut,
padding: EdgeInsets.only(top: animatedPadding),
child: child),
);
},
child: Text(
text,
style: const TextStyle(
color: Colors.white,
fontSize: 24.0,
),
),
);
}
add animatedText in Container ;
Container(alignment: Alignment.center,
height: Sizes.height * 0.05,
width: Sizes.width * 0.1,
child: animatedText(second.toString(), sp)),

Related

Resizing a rotated container in flutter from corners and middle points ( 8 points)

I am developing an shape editor in flutter. For that, I need to add a feature of adding shapes dynamically to the screen. Each of them should be able to independently scale, position, and rotate. There should be an anchor point like in word or in Photoshop to indicate the active shapes and to scale and rotate them. The shape should be positioned with drag and drop.
I found this answer :
Rotate and resize container
But the answer only rotate the shape from the center, I want to scale the shape from the corners also.
The code :
class FooResizer extends StatefulWidget {
#override
_FooResizerState createState() => _FooResizerState();
}
class _FooResizerState extends State<FooResizer> with TickerProviderStateMixin, ChangeNotifier {
Sizer currentSizer;
double angle = 0.0;
AnimationController ctrl;
final Map<String, Sizer> sizers = {
'l': Sizer('l', Alignment.centerLeft, {'t': 0.5, 'b': 0.5, 'M': 0.5}),
't': Sizer('t', Alignment.topCenter, {'l': 0.5, 'r': 0.5, 'M': 0.5}),
'r': Sizer('r', Alignment.centerRight, {'t': 0.5, 'b': 0.5, 'R': 1.0, 'M': 0.5}),
'b': Sizer('b', Alignment.bottomCenter, {'l': 0.5, 'r': 0.5, 'R': 1.0, 'M': 0.5}),
'R': Sizer('R', Alignment.bottomRight, {}),
'M': Sizer('M', Alignment.center, {}),
};
#override
void initState() {
super.initState();
ctrl = AnimationController(vsync: this, duration: Duration(milliseconds: 300), value: 1.0);
}
#override
Widget build(BuildContext context) {
return ClipRect(
child: ColoredBox(
color: Colors.black12,
// CustomMultiChildLayoutPainter:
// https://gist.github.com/pskink/0f82724b41d9ebe89604782fbf62fe03#file-multi_layout_painter-dart-L447
child: CustomMultiChildLayoutPainter(
delegate: _FooResizerDelegate(sizers, this),
children: [
LayoutId(
id: 'body',
child: AnimatedBuilder(
animation: this,
builder: (ctx, child) {
return Transform.rotate(
angle: angle,
child: child,
);
},
child: Material(color: Colors.grey[300], elevation: 4, child: FlutterLogo()),
),
),
...sizers.values.map(_sizerBuilder),
],
),
),
);
}
Widget _sizerBuilder(Sizer sizer) {
final colors = {
'M': Colors.orange,
'R': Colors.teal,
};
return LayoutId(
id: sizer.id,
child: GestureDetector(
onPanStart: (details) => _panStart(sizer),
onPanUpdate: _panUpdate,
onPanEnd: _panEnd,
child: AnimatedBuilder(
animation: ctrl,
builder: (context, child) {
final color = colors[sizer.id] ?? Colors.green;
return Opacity(
opacity: currentSizer == sizer? 1.0 : Curves.ease.transform(ctrl.value),
child: Container(
decoration: ShapeDecoration(
shape: CircleBorder(side: BorderSide(width: lerpDouble(0.0, 2.0, ctrl.value), color: Colors.black38)),
color: currentSizer == sizer? Color.lerp(Colors.deepPurple, color, ctrl.value) : color,
shadows: [BoxShadow.lerp(BoxShadow(spreadRadius: 2, blurRadius: 4, offset: Offset(2, 2)), null, ctrl.value)],
),
),
);
}
),
),
);
}
_panStart(Sizer sizer) {
currentSizer = sizer;
ctrl.reverse();
}
_panUpdate(DragUpdateDetails details) {
assert(currentSizer != null);
if (currentSizer.id == 'M') {
// move
sizers.values.forEach((sizer) => sizer.center += details.delta);
} else
if (currentSizer.id == 'R') {
// rotate
final localCenter = sizers['M'].center;
final globalCenter = (context.findRenderObject() as RenderBox).localToGlobal(localCenter);
final angle0 = (details.globalPosition - details.delta - globalCenter).direction;
final angle1 = (details.globalPosition - globalCenter).direction;
final deltaAngle = angle1 - angle0;
sizers.values
.where((sizer) => sizer.id != 'M')
.forEach((sizer) {
final vector = sizer.center - localCenter;
sizer.center = localCenter + Offset.fromDirection(vector.direction + deltaAngle, vector.distance);
});
angle += deltaAngle;
} else {
// resize
final adjustedAngle = angle + currentSizer.angleAdjustment;
final rotatedDistance = details.delta.distance * math.cos(details.delta.direction - adjustedAngle);
final vector = Offset.fromDirection(adjustedAngle, rotatedDistance);
currentSizer.center += vector;
currentSizer.dependents.forEach((id, factor) => sizers[id].center += vector * factor);
}
notifyListeners();
}
_panEnd(DragEndDetails details) {
assert(currentSizer != null);
// currentSizer = null;
ctrl.forward();
}
}
class _FooResizerDelegate extends MultiChildLayoutPainterDelegate {
static const SIZE = 48.0;
final Map<String, Sizer> sizers;
_FooResizerDelegate(this.sizers, Listenable relayout) : super(relayout: relayout);
#override
void performLayout(Size size) {
sizers['M'].center ??= init(size);
for (var sizer in sizers.values) {
layoutChild(sizer.id, BoxConstraints.tight(Size(SIZE, SIZE)));
positionChild(sizer.id, sizer.center - Offset(SIZE / 2, SIZE / 2));
}
final w = (sizers['l'].center - sizers['r'].center).distance;
final h = (sizers['t'].center - sizers['b'].center).distance;
layoutChild('body', BoxConstraints.tight(Size(w, h)));
positionChild('body', sizers['M'].center - Offset(w / 2, h / 2));
}
Offset init(Size size) {
final rect = (Offset.zero & size).deflate(24);
print('init rect: $rect');
for (var sizer in sizers.values) {
sizer
..center = sizer.alignment.withinRect(rect)
..angleAdjustment = sizer.alignment.x == 0? math.pi / 2 : 0;
}
return sizers['M'].center;
}
#override
bool shouldRelayout(covariant MultiChildLayoutDelegate oldDelegate) => true;
#override
void foregroundPaint(Canvas canvas, Size size) {
}
#override
void paint(Canvas canvas, Size size) {
final w = (sizers['r'].center - sizers['l'].center).distance;
final h = (sizers['b'].center - sizers['t'].center).distance;
final rect = Rect.fromCenter(center: sizers['M'].center, width: w, height: h);
final angle = (sizers['r'].center - sizers['l'].center).direction;
final matrix = Matrix4.identity()
..translate(rect.center.dx, rect.center.dy)
..rotateZ(angle)
..translate(-rect.center.dx, -rect.center.dy);
final transformedRect = MatrixUtils.transformRect(matrix, rect);
final points = [
Offset(transformedRect.left, 0), Offset(transformedRect.left, size.height),
Offset(0, transformedRect.top), Offset(size.width, transformedRect.top),
Offset(transformedRect.right, 0), Offset(transformedRect.right, size.height),
Offset(0, transformedRect.bottom), Offset(size.width, transformedRect.bottom),
];
canvas.drawPoints(PointMode.lines, points, Paint());
}
}
class Sizer {
final String id;
final Alignment alignment;
final Map<String, double> dependents;
Offset center;
double angleAdjustment;
Sizer(this.id, this.alignment, this.dependents);
}
The result :
what I am trying to achieve :

how to add multiple sliders on one slider? #Flutter

I want to add multiple sliders in one slider. If you're not clear about what I'm asking please refer the below image
I want these three squares to be sliding and get the values of them.
I did some searching and could not find any flutter widget or a plugin that has the support.
I tried to use a stack and use multiple Slider widgets at the same location but it is also not working. (I know it's not a good approach.)
How can I make this happen. To have multiple sliders on the same line and get the values.
Any help or ideas are very much appreciated.

Using Stack with three sliders did not work because it was being overlapped.
I have made this Slider3X of being curious. There are few things need to fix here, start and end points missing some fractional position.
Code on Gist, dart pad
class Slider3x extends StatefulWidget {
const Slider3x({
Key? key,
required this.onSliderUpdate,
this.size = const Size(5, 10),
this.min = 0,
this.max = 1.0,
this.colorX = Colors.green,
this.colorY = Colors.blue,
this.colorZ = Colors.redAccent,
}) : super(key: key);
final Function(double? x, double? y, double? z) onSliderUpdate;
///size of moveable 3x point 😅, forgot the name maybe thumbs
final Size size;
final double? min;
final double? max;
final Color colorX;
final Color colorY;
final Color colorZ;
#override
State<Slider3x> createState() => _Slider3xState();
}
class _Slider3xState extends State<Slider3x> {
/// three slider position
double? x;
double? y;
double? z;
final double tapSpacesArea = .05;
// currect active slider , help to prevent overlLAp while sliding
int activeSliderNumber = 0;
//* Update sldier
void _updateSlider(double dx, double maxWidth) {
final tapPosition = dx;
//* update logic
if (tapPosition <= 0 || tapPosition >= maxWidth) {
return;
}
//* update on UI based on slider number
if (activeSliderNumber == 0) {
setState(() {
x = tapPosition;
});
} else if (activeSliderNumber == 1) {
setState(() {
y = tapPosition;
});
} else if (activeSliderNumber == 2) {
setState(() {
z = tapPosition;
});
}
//pass value on main widget
widget.onSliderUpdate(
dp(_generateSliderValue(maxWidth: maxWidth, x: x!)),
dp(_generateSliderValue(maxWidth: maxWidth, x: y!)),
dp(_generateSliderValue(maxWidth: maxWidth, x: z!)),
);
}
//round number
double dp(double val, {int places = 2}) {
num mod = pow(10.0, places);
return ((val * mod).round().toDouble() / mod);
}
//* calculate slider value
double _generateSliderValue({
required double maxWidth,
required double x,
}) {
// x is slider original position on width:maxWidth
return (widget.max! - widget.min!) * (x / maxWidth) + widget.min!;
}
//* select ActiveSlider, fixed overLap issue
//* slider Selector logic
void _selectSlider({
required double maxWidth,
required double tapPosition,
}) {
final maxArea = maxWidth * tapSpacesArea;
if ((tapPosition - x!).abs() < maxArea) {
setState(() {
activeSliderNumber = 0;
});
} else if ((tapPosition - y!).abs() < maxArea) {
setState(() {
activeSliderNumber = 1;
});
} else if ((tapPosition - z!).abs() < maxArea) {
setState(() {
activeSliderNumber = 2;
});
}
}
#override
Widget build(BuildContext context) {
return Padding(
padding: const EdgeInsets.all(8.0),
child: Column(
mainAxisSize: MainAxisSize.min,
children: [
SizedBox(
height: 50,
child: LayoutBuilder(builder: (context, constraints) {
final maxWidth = constraints.maxWidth - 10;
x = x ?? 0;
y = y ?? constraints.maxWidth / 2;
z = z ?? maxWidth;
return Stack(
alignment: Alignment.center,
children: [
Positioned(
left: x,
child: Container(
height: activeSliderNumber == 0
? widget.size.height * 1.5
: widget.size.height,
width: widget.size.width,
color: widget.colorX,
),
),
//* paint Y
Positioned(
left: y,
child: Container(
height: activeSliderNumber == 1
? widget.size.height * 1.5
: widget.size.height,
width: widget.size.width,
color: widget.colorY,
),
),
//* paint z
Positioned(
left: z,
child: Container(
height: activeSliderNumber == 2
? widget.size.height * 1.5
: widget.size.height,
width: widget.size.width,
color: widget.colorZ,
),
),
const Divider(
endIndent: 10,
),
GestureDetector(
onTapDown: (details) => _selectSlider(
maxWidth: maxWidth,
tapPosition: details.localPosition.dx),
onPanUpdate: (details) =>
_updateSlider(details.localPosition.dx, maxWidth),
),
],
);
}),
),
Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: [
Text(
widget.min.toString(),
),
Text(
widget.max.toString(),
),
],
)
],
),
);
}
}

How to set any widget on screen at specific position with responsiveness in flutter

I am trying to set any widget to screen at any position so if user open app in other devices the widget must should remain at that give position , for example if I set widget on 1/4 part of the screen then it should be the same in every device . I tested in simulator from Iphone 8 to Ipad 8th gen.
Below is my code I am using Positioned.fromRect and passing Offset(dx,dy). I also tried MediaQuery but all in vain . Please guide me even if you find my question stupid.
Reference app Story click or post maker app with pre built in templates.
This is simple constructor.
FlutterSimpleStickerImage(
this.image, {
Key key,
this.width,
this.height,
this.viewport,
this.minScale = 1.0,
this.maxScale = 2.0,
this.onTapRemove,
}) : super(key: key);
Widget image;
final double width;
final double height;
final Size viewport;
final double minScale;
final double maxScale;
A class for positioning widget in stack the Position.fromRect()
class _FlutterSimpleStickerImageState extends State<FlutterSimpleStickerImage> {
_FlutterSimpleStickerImageState();
double _scale = 1.0;
double _previousScale = 1.0;
Offset _previousOffset = Offset(0, 0);
Offset _startingFocalPoint = Offset(0, 0);
Offset _offset = Offset(0, 0);
double _rotation = 0.0;
double _previousRotation = 0.0;
bool _isSelected = false;
#override
void dispose() {
super.dispose();
_offset = Offset(0, 0);
_scale = 1.0;
}
#override
Widget build(BuildContext context) {
double sizewidth=183;
double sizeheight=0;
return Positioned.fromRect(
rect: Rect.fromPoints(Offset(sizewidth, sizeheight),Offset(sizewidth , sizeheight )),
child: Container(
child: Stack(
children: <Widget>[
Center(
child: Transform(
transform: Matrix4.diagonal3(Vector3(_scale, _scale, _scale)),
// ..setRotationZ(_rotation),
alignment: FractionalOffset.center,
child: GestureDetector(
onScaleStart: (ScaleStartDetails details) {
_startingFocalPoint = Offset(sizewidth,sizeheight);
_previousOffset = Offset(sizewidth,sizeheight);
_previousRotation = _rotation;
_previousScale = _scale;
// print(
// "begin - focal : ${details.focalPoint}, local : ${details.localFocalPoint}");
},
onScaleUpdate: (ScaleUpdateDetails details) {
_scale = min(
max(_previousScale * details.scale, widget.minScale),
widget.maxScale);
_rotation = details.rotation;
final Offset normalizedOffset =
(_startingFocalPoint - _previousOffset) /
_previousScale;
Offset __offset =
details.focalPoint - (normalizedOffset * _scale);
__offset = Offset(max(__offset.dx, -widget.width),
max(__offset.dy, -widget.height));
__offset = Offset(min(__offset.dx, widget.viewport.width),
min(__offset.dy, widget.viewport.height));
setState(() {
_offset = __offset;
// print("move - $_offset, scale : $_scale");
});
},
onTap: () {
setState(() {
_isSelected = !_isSelected;
});
},
onTapCancel: () {
setState(() {
_isSelected = false;
});
},
onDoubleTap: () {
setState(() {
_scale = 1.0;
});
},
onLongPress: (){
setState(() {
widget.image=Container(height: 100,width: 100,color: Color.fromRGBO(255, 150, 0, 1.0),);
});
},
child: Container(child: widget.image),
),
),
),
_isSelected
? Positioned(
top: 12,
right: 12,
width: 24,
height: 24,
child: Container(
child: IconButton(
padding: EdgeInsets.zero,
icon: Icon(Icons.remove_circle),
color: Color.fromRGBO(255, 150, 0, 1.0),
onPressed: () {
print('tapped remove sticker');
if (this.widget.onTapRemove != null) {
this.widget.onTapRemove(this.widget);
}
},
),
),
)
: Container(),
],
),
),
);
}
void hideRemoveButton() {
setState(() {
_isSelected = false;
});
}
}

'The method 'call' was called on null.' in Flutter

I am trying to extract a value, touchedIndex, from a child widget PieChartWidget that I have to make a pie chart with a hole in the middle using fl_chart, into its parent widget Co2Tracker to allow me to create some text in the middle of the pie chart that changes when a segment of the pie chart is pressed. This returns an error but everything works visually other than the pie chart segments no longer expand.To make debugging easier I replaced the setState(){isTouched = isTouchedNew} with print(isTouchedNew) but this still returns the error below, however, the pie chart now expands.
PieChart example
When using a callback function
int isTouched = -1;
setIsTouched(int isTouchedNew) {
print(isTouchedNew);
}
integrated within a stateful widget I get an output of
════════ Exception caught by gesture ═══════════════════════════════════════════════════════════════
The method 'call' was called on null.
Receiver: null
Tried calling: call(-1)
parent main page
class Co2Tracker extends StatefulWidget {
#override
_Co2TrackerState createState() => _Co2TrackerState();
}
class _Co2TrackerState extends State<Co2Tracker> {
List<String> pieNames = ['Travel', 'Gas', 'Electricity', 'Food shop', 'Water',];
int isTouched = -1;
double radiusNormal = 60;
double centerRadius = 50;
double radiusExpansion = 1.2;
setIsTouched(int isTouchedNew) {
print(isTouchedNew);
}
#override
Widget build(BuildContext context) {
//double co2 = ModalRoute.of(context).settings.arguments;
return Scaffold(
appBar: appBarTemplate('CO\u2082 Tracker'),
body: Column(
children: <Widget>[
Padding(
padding: const EdgeInsets.symmetric(vertical: 15),
child: textStyleTemplateLarge(text: 'Your CO\u2082 emissions today', textColor: Colors.green[400]),
),
AspectRatio(
aspectRatio: 200/((radiusExpansion*radiusNormal) + centerRadius),
child: Row(
children: <Widget>[
Expanded(
child: Stack(
children: <Widget>[
Center(
child: FlatButton(child: textStyleTemplateLarge(text: '70kg', textColor: Colors.black),),
),
Center(
child: PieChartWidget(radiusNormal: radiusNormal, centerRadius: centerRadius, radiusExpanded: (radiusExpansion*radiusNormal), pieNames: pieNames,),
),
],
),
),
],
),
),
],
),
);
}
}
child pie chart widget
import 'package:flutter/material.dart';
import 'package:fl_chart/fl_chart.dart';
class PieChartWidget extends StatefulWidget {
final double radiusNormal;
final double radiusExpanded;
final double centerRadius;
final double fontSizeNormal;
final double fontSizeExpanded;
final List<String> pieNames;
final Function(int) setIsTouched;
PieChartWidget({this.radiusNormal, this.radiusExpanded, this.centerRadius, this.fontSizeNormal, this.fontSizeExpanded, this.pieNames, this.setIsTouched});
#override
_PieChartWidgetState createState() => _PieChartWidgetState(radiusNormal: radiusNormal, radiusExpanded: radiusExpanded, centerRadius: centerRadius,
fontSizeNormal: fontSizeNormal, fontSizeExpanded: fontSizeExpanded, pieNames: pieNames, setIsTouched: setIsTouched,);
}
class _PieChartWidgetState extends State<PieChartWidget> {
int touchedIndex = -1;
double radiusNormal;
double radiusExpanded;
double centerRadius;
double fontSizeNormal;
double fontSizeExpanded;
List<String> pieNames;
Function(int) setIsTouched;
_PieChartWidgetState({this.radiusNormal = 50, this.radiusExpanded = 60, this.centerRadius = 40, this.fontSizeNormal = 16, this.fontSizeExpanded = 25,
this.pieNames, this.setIsTouched,});
#override
Widget build(BuildContext context) {
return PieChart(
PieChartData(
sections: pieSections(pieNames),
borderData: FlBorderData(show: false),
sectionsSpace: 0,
centerSpaceRadius: centerRadius,
pieTouchData: PieTouchData(touchCallback: (pieTouchResponse) {
setState(() {
if (pieTouchResponse.touchInput is FlLongPressEnd ||
pieTouchResponse.touchInput is FlPanEnd) {
touchedIndex = -1;
} else {
touchedIndex = pieTouchResponse.touchedSectionIndex;
}
});
widget.setIsTouched(touchedIndex);
}),
),
);
}
-----------------I-think-everything-below-this-is-irrelevant-but-I-could-be-wrong-------------------------------------------
List<PieChartSectionData> pieSections(List<String> pieNames,) {
return List.generate(5, (i) {
final isTouched = i == touchedIndex;
final double fontSize = isTouched ? 25 : 16;
final double radius = isTouched ? radiusExpanded : radiusNormal;
final int colorNumber = (1+i) * 100;
final List<double> valueList = [20, 10, 10, 20, 30];
final double total = valueList.fold(0, (a, b) => a+b);
switch (i) {
case 0:
return sectionData(valueList[i], Colors.pink[300], title(isTouched, valueList[i], total, pieNames[i]), radius, fontSize);
case 1:
return sectionData(valueList[i], Colors.blue[600], title(isTouched, valueList[i], total, pieNames[i]), radius, fontSize);
case 2:
return sectionData(valueList[i], Colors.amber[300], title(isTouched, valueList[i], total, pieNames[i]), radius, fontSize);
case 3:
return sectionData(valueList[i], Colors.purple[300], title(isTouched, valueList[i], total, pieNames[i]), radius, fontSize);
case 4:
return sectionData(valueList[i], Colors.blue[300], title(isTouched, valueList[i], total, pieNames[i]), radius, fontSize);
default:
return null;
}
});
}
PieChartSectionData sectionData(double value, Color color, String title, double radius, double fontSize,){
return PieChartSectionData(
value: value, color: color, title: title, radius: radius,
titleStyle: TextStyle(color: Colors.black, fontSize: fontSize, fontWeight: FontWeight.bold),
);
}
String title(bool isTouched, double value, double total, String title,) {
return isTouched ? '${double.parse((value/total*100).toStringAsFixed(2))}%' : '$title';
}
}
My thoughts so far have been that maybe it is to do with initialization of variables or maybe this touchCallback function from the child page line 43 but no luck so far.
Thanks in advance for your time.

The problem is that when your printing an integer.
setIsTouched(int isTouchedNew) { print(isTouchedNew); }
You're supposed to print it like this
print("${isTouchedNew}")

Umm..not sure if you tried this,
int isTouched = -1;
setIsTouched(int isTouchedNew) {
setState(() {
isTouched=isTouchedNew;
print(isTouchedNew);
}
}

Changing colour of CustomPaint changes for all previous points

So I'm trying to create a draw app using Flutter following the "signature canvas" method. However, I'm having trouble being able to change the colour of the CustomPaint object without it already changing the colours for each line draw before the change as shown here:
As you can see, the colour change happens once the Page Widget's state is changed (either by clicking on the main FAB or if I were to draw on the canvas again). Here is my code below for my DrawPage:
class DrawPage extends StatefulWidget {
#override
DrawPageState createState() => new DrawPageState();
}
class DrawPageState extends State<DrawPage> with TickerProviderStateMixin {
AnimationController controller;
List<Offset> points = <Offset>[];
Color color = Colors.black;
StrokeCap strokeCap = StrokeCap.round;
double strokeWidth = 5.0;
#override
void initState() {
super.initState();
controller = new AnimationController(
vsync: this,
duration: const Duration(milliseconds: 500),
);
}
#override
Widget build(BuildContext context) {
return Scaffold(
body: Container(
child: GestureDetector(
onPanUpdate: (DragUpdateDetails details) {
setState(() {
RenderBox object = context.findRenderObject();
Offset localPosition =
object.globalToLocal(details.globalPosition);
points = new List.from(points);
points.add(localPosition);
});
},
onPanEnd: (DragEndDetails details) => points.add(null),
child: CustomPaint(
painter: Painter(
points: points,
color: color,
strokeCap: strokeCap,
strokeWidth: strokeWidth),
size: Size.infinite,
),
),
),
floatingActionButton:
Column(mainAxisSize: MainAxisSize.min, children: <Widget>[
Container(
height: 70.0,
width: 56.0,
alignment: FractionalOffset.topCenter,
child: ScaleTransition(
scale: CurvedAnimation(
parent: controller,
curve: Interval(0.0, 1.0 - 0 / 3 / 2.0, curve: Curves.easeOut),
),
child: FloatingActionButton(
mini: true,
child: Icon(Icons.clear),
onPressed: () {
points.clear();
},
),
),
),
Container(
height: 70.0,
width: 56.0,
alignment: FractionalOffset.topCenter,
child: ScaleTransition(
scale: CurvedAnimation(
parent: controller,
curve: Interval(0.0, 1.0 - 1 / 3 / 2.0, curve: Curves.easeOut),
),
child: FloatingActionButton(
mini: true,
child: Icon(Icons.lens),
onPressed: () {},
),
),
),
Container(
height: 70.0,
width: 56.0,
alignment: FractionalOffset.topCenter,
child: ScaleTransition(
scale: CurvedAnimation(
parent: controller,
curve:
Interval(0.0, 1.0 - 2 / 3 / 2.0, curve: Curves.easeOut),
),
child: FloatingActionButton(
mini: true,
child: Icon(Icons.color_lens),
onPressed: () async {
Color temp;
temp = await showDialog(
context: context,
builder: (context) => ColorDialog());
if (temp != null) {
setState(() {
color = temp;
});
}
}))),
FloatingActionButton(
child: AnimatedBuilder(
animation: controller,
builder: (BuildContext context, Widget child) {
return Transform(
transform: Matrix4.rotationZ(controller.value * 0.5 * math.pi),
alignment: FractionalOffset.center,
child: Icon(Icons.brush),
);
},
),
onPressed: () {
if (controller.isDismissed) {
controller.forward();
} else {
controller.reverse();
}
},
),
]),
);
}
}
What I've tried so far:
I've tried playing around with how the points are added to my List of Offsets as this list is recreated after each "draw" gesture such as just adding to the current List without recreating it but this breaks the "draw" gesture:
setState(() {
RenderBox object = context.findRenderObject();
Offset localPosition =
object.globalToLocal(details.globalPosition);
points = new List.from(points);
points.add(localPosition);
});
I've tried making a reference to the CustomPaint object or my Painter object outside of the build() scope and updating the color property that way but this also breaks the "draw" gesture.
Any help would be greatly appreciated!
Also, here's the code for my Painter class in case people wish to see it:
class Painter extends CustomPainter {
List<Offset> points;
Color color;
StrokeCap strokeCap;
double strokeWidth;
Painter({this.points, this.color, this.strokeCap, this.strokeWidth});
#override
void paint(Canvas canvas, Size size) {
Paint paint = new Paint();
paint.color = color;
paint.strokeCap = strokeCap;
paint.strokeWidth = strokeWidth;
for (int i = 0; i < points.length - 1; i++) {
if (points[i] != null && points[i + 1] != null) {
canvas.drawLine(points[i], points[i + 1], paint);
}
}
}
#override
bool shouldRepaint(Painter oldPainter) => oldPainter.points != points;
}

I think, for different colors you have to use different Paints. I've added small changes to your code, it works.
class DrawPageState extends State<DrawPage> with TickerProviderStateMixin {
...
List<Painter> painterList = [];
#override
Widget build(BuildContext context) {
...
child: CustomPaint(
painter: Painter(
points: points, color: color, strokeCap: strokeCap, strokeWidth: strokeWidth, painters: painterList),
size: Size.infinite,
),
...
onPressed: () async {
Color temp;
temp = await showDialog(
context: context,
builder: (context) => ColorDialog());
if (temp != null) {
setState(() {
painterList
.add(Painter(points: points.toList(), color: color, strokeCap: strokeCap, strokeWidth: strokeWidth));
points.clear();
strokeCap = StrokeCap.round;
strokeWidth = 5.0;
color = temp;
});
}
...
}
}
class Painter extends CustomPainter {
List<Offset> points;
Color color;
StrokeCap strokeCap;
double strokeWidth;
List<Painter> painters;
Painter({this.points, this.color, this.strokeCap, this.strokeWidth, this.painters = const []});
#override
void paint(Canvas canvas, Size size) {
for (Painter painter in painters) {
painter.paint(canvas, size);
}
Paint paint = new Paint()
..color = color
..strokeCap = strokeCap
..strokeWidth = strokeWidth;
for (int i = 0; i < points.length - 1; i++) {
if (points[i] != null && points[i + 1] != null) {
canvas.drawLine(points[i], points[i + 1], paint);
}
}
}
#override
bool shouldRepaint(Painter oldDelegate) => oldDelegate.points != points;
}

2020, I have a nice solution for this, because the actually chosen doesn't work for me and I see some redundant calls.
So, I start creating a small class:
class _GroupPoints {
Offset offset;
Color color;
_GroupPoints({this.offset, this.color});
}
next, i declare my CustomPainter like this:
class Signature extends CustomPainter {
List<_GroupPoints> points;
Color color;
Signature({
this.color,
this.points,
});
#override
void paint(Canvas canvas, Size size) {
Paint paint = new Paint()
// if you need this next params as dynamic, you can move it inside the for part
..strokeCap = StrokeCap.round
..strokeWidth = 5.0;
for (int i = 0; i < newPoints.length - 1; i++) {
paint.color = points[i].color;
if (points[i].offset != null && points[i + 1].offset != null) {
canvas.drawLine(points[i].offset, points[i + 1].offset, paint);
}
canvas.clipRect(Offset.zero & size);
}
}
#override
bool shouldRepaint(Signature oldDelegate) => true;
}
And on my widget:
...
class _MyPageState extends State<MyPage> {
...
List<_GroupPoints> points = [];
...
Container(
height: 500,
width: double.infinity,
child: GestureDetector(
onPanUpdate: (DragUpdateDetails details) {
setState(() {
points = new List.from(points)
..add(
new _GroupPoints(
offset: details.localPosition,
color: myDynamicColor,
),
);
});
},
onPanEnd: (DragEndDetails details) {
points.add(
_GroupPoints(
color: myDynamicColor,
offset: null),
);
},
child: CustomPaint(
painter: Signature(
newPoints: points,
color: myDynamicColor,
),
),
),
),
}
On this way we can use multiple draws of points with their respective color. Hope this can help anybody.

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