问题
I just succeed flutter-flare for my flutter widgets
but I could not find a example to use it for background (Container)
is this possible?
回答1:
Use official example code https://github.com/2d-inc/Flare-Flutter/tree/stable/example/teddy/lib
with a little modification, you can use Stack and Positioned and change attribute value like top
code snippet
return Scaffold(
backgroundColor: Color.fromRGBO(93, 142, 155, 1.0),
body: Container(
child: Stack(
children: <Widget>[
Positioned(
top: 50,
left:0,
right: 0,
child: Container(
height: 200,
padding:
const EdgeInsets.only(left: 30.0, right: 30.0),
child: FlareActor(
"assets/Teddy.flr",
shouldClip: false,
alignment: Alignment.bottomCenter,
fit: BoxFit.contain,
controller: _teddyController,
)),),
Positioned(
child: SingleChildScrollView(
working demo
full code
import 'package:flutter/material.dart';
import 'package:flare_flutter/flare_actor.dart';
import 'package:flutter/rendering.dart';
import 'dart:async';
import 'dart:math';
import 'dart:ui';
import 'package:flare_flutter/flare.dart';
import 'package:flare_dart/math/mat2d.dart';
import 'package:flare_dart/math/vec2d.dart';
import 'package:flare_flutter/flare_controls.dart';
// Adapted these helpful functions from:
// https://github.com/flutter/flutter/blob/master/packages/flutter/test/material/text_field_test.dart
// Returns first render editable
RenderEditable findRenderEditable(RenderObject root) {
RenderEditable renderEditable;
void recursiveFinder(RenderObject child) {
if (child is RenderEditable) {
renderEditable = child;
return;
}
child.visitChildren(recursiveFinder);
}
root.visitChildren(recursiveFinder);
return renderEditable;
}
List<TextSelectionPoint> globalize(
Iterable<TextSelectionPoint> points, RenderBox box) {
return points.map<TextSelectionPoint>((TextSelectionPoint point) {
return TextSelectionPoint(
box.localToGlobal(point.point),
point.direction,
);
}).toList();
}
Offset getCaretPosition(RenderBox box) {
final RenderEditable renderEditable = findRenderEditable(box);
if (!renderEditable.hasFocus) {
return null;
}
final List<TextSelectionPoint> endpoints = globalize(
renderEditable.getEndpointsForSelection(renderEditable.selection),
renderEditable,
);
return endpoints[0].point + const Offset(0.0, -2.0);
}
class SigninButton extends StatelessWidget {
final Widget child;
final Gradient gradient;
final double width;
final double height;
final Function onPressed;
const SigninButton({
Key key,
@required this.child,
this.gradient,
this.width = double.infinity,
this.height = 50.0,
this.onPressed,
}) : super(key: key);
@override
Widget build(BuildContext context) {
return Container(
width: width,
height: 50.0,
decoration: BoxDecoration(
borderRadius: BorderRadius.circular(25.0),
gradient: LinearGradient(
colors: <Color>[
Color.fromRGBO(160, 92, 147, 1.0),
Color.fromRGBO(115, 82, 135, 1.0)
],
)),
child: Material(
color: Colors.transparent,
child: InkWell(
onTap: onPressed,
child: Center(
child: child,
)),
),
);
}
}
class TeddyController extends FlareControls {
// Store a reference to our face control node (the "ctrl_look" node in Flare)
ActorNode _faceControl;
// Storage for our matrix to get global Flutter coordinates into Flare world coordinates.
Mat2D _globalToFlareWorld = Mat2D();
// Caret in Flutter global coordinates.
Vec2D _caretGlobal = Vec2D();
// Caret in Flare world coordinates.
Vec2D _caretWorld = Vec2D();
// Store the origin in both world and local transform spaces.
Vec2D _faceOrigin = Vec2D();
Vec2D _faceOriginLocal = Vec2D();
bool _hasFocus = false;
// Project gaze forward by this many pixels.
static const double _projectGaze = 60.0;
String _password;
@override
bool advance(FlutterActorArtboard artboard, double elapsed) {
super.advance(artboard, elapsed);
Vec2D targetTranslation;
if (_hasFocus) {
// Get caret in Flare world space.
Vec2D.transformMat2D(_caretWorld, _caretGlobal, _globalToFlareWorld);
// To make it more interesting, we'll also add a sinusoidal vertical offset.
_caretWorld[1] +=
sin(new DateTime.now().millisecondsSinceEpoch / 300.0) * 70.0;
// Compute direction vector.
Vec2D toCaret = Vec2D.subtract(Vec2D(), _caretWorld, _faceOrigin);
Vec2D.normalize(toCaret, toCaret);
Vec2D.scale(toCaret, toCaret, _projectGaze);
// Compute the transform that gets us in face "ctrl_face" space.
Mat2D toFaceTransform = Mat2D();
if (Mat2D.invert(toFaceTransform, _faceControl.parent.worldTransform)) {
// Put toCaret in local space, note we're using a direction vector
// not a translation so transform without translation
Vec2D.transformMat2(toCaret, toCaret, toFaceTransform);
// Our final "ctrl_face" position is the original face translation plus this direction vector
targetTranslation = Vec2D.add(Vec2D(), toCaret, _faceOriginLocal);
}
} else {
targetTranslation = Vec2D.clone(_faceOriginLocal);
}
// We could just set _faceControl.translation to targetTranslation, but we want to animate it smoothly to this target
// so we interpolate towards it by a factor of elapsed time in order to maintain speed regardless of frame rate.
Vec2D diff =
Vec2D.subtract(Vec2D(), targetTranslation, _faceControl.translation);
Vec2D frameTranslation = Vec2D.add(Vec2D(), _faceControl.translation,
Vec2D.scale(diff, diff, min(1.0, elapsed * 5.0)));
_faceControl.translation = frameTranslation;
return true;
}
// Fetch references for the `ctrl_face` node and store a copy of its original translation.
@override
void initialize(FlutterActorArtboard artboard) {
super.initialize(artboard);
_faceControl = artboard.getNode("ctrl_face");
if (_faceControl != null) {
_faceControl.getWorldTranslation(_faceOrigin);
Vec2D.copy(_faceOriginLocal, _faceControl.translation);
}
play("idle");
}
onCompleted(String name) {
play("idle");
}
// Called by [FlareActor] when the view transform changes.
// Updates the matrix that transforms Global-Flutter-coordinates into Flare-World-coordinates.
@override
void setViewTransform(Mat2D viewTransform) {
Mat2D.invert(_globalToFlareWorld, viewTransform);
}
// Transform the [Offset] into a [Vec2D].
// If no caret is provided, lower the [_hasFocus] flag.
void lookAt(Offset caret) {
if (caret == null) {
_hasFocus = false;
return;
}
_caretGlobal[0] = caret.dx;
_caretGlobal[1] = caret.dy;
_hasFocus = true;
}
void setPassword(String value) {
_password = value;
}
bool _isCoveringEyes = false;
coverEyes(cover) {
if (_isCoveringEyes == cover) {
return;
}
_isCoveringEyes = cover;
if (cover) {
play("hands_up");
} else {
play("hands_down");
}
}
void submitPassword() {
if (_password == "bears") {
play("success");
} else {
play("fail");
}
}
}
typedef void CaretMoved(Offset globalCaretPosition);
typedef void TextChanged(String text);
// Helper widget to track caret position.
class TrackingTextInput extends StatefulWidget {
TrackingTextInput(
{Key key, this.onCaretMoved, this.onTextChanged, this.hint, this.label, this.isObscured = false})
: super(key: key);
final CaretMoved onCaretMoved;
final TextChanged onTextChanged;
final String hint;
final String label;
final bool isObscured;
@override
_TrackingTextInputState createState() => _TrackingTextInputState();
}
class _TrackingTextInputState extends State<TrackingTextInput> {
final GlobalKey _fieldKey = GlobalKey();
final TextEditingController _textController = TextEditingController();
Timer _debounceTimer;
@override
initState() {
_textController.addListener(() {
// We debounce the listener as sometimes the caret position is updated after the listener
// this assures us we get an accurate caret position.
if (_debounceTimer?.isActive ?? false) _debounceTimer.cancel();
_debounceTimer = Timer(const Duration(milliseconds: 100), () {
if (_fieldKey.currentContext != null) {
// Find the render editable in the field.
final RenderObject fieldBox =
_fieldKey.currentContext.findRenderObject();
Offset caretPosition = getCaretPosition(fieldBox);
if (widget.onCaretMoved != null) {
widget.onCaretMoved(caretPosition);
}
}
});
if (widget.onTextChanged != null) {
widget.onTextChanged(_textController.text);
}
});
super.initState();
}
@override
Widget build(BuildContext context) {
return Padding(
padding: const EdgeInsets.only(bottom: 20.0),
child: TextFormField(
decoration: InputDecoration(
hintText: widget.hint,
labelText: widget.label,
),
key: _fieldKey,
controller: _textController,
obscureText: widget.isObscured,
validator: (value) {}),
);
}
}
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
final String title;
@override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
TeddyController _teddyController;
@override
initState() {
_teddyController = TeddyController();
super.initState();
}
@override
Widget build(BuildContext context) {
EdgeInsets devicePadding = MediaQuery.of(context).padding;
return Scaffold(
backgroundColor: Color.fromRGBO(93, 142, 155, 1.0),
body: Container(
child: Stack(
children: <Widget>[
Positioned(
top: 50,
left:0,
right: 0,
child: Container(
height: 200,
padding:
const EdgeInsets.only(left: 30.0, right: 30.0),
child: FlareActor(
"assets/Teddy.flr",
shouldClip: false,
alignment: Alignment.bottomCenter,
fit: BoxFit.contain,
controller: _teddyController,
)),),
Positioned(
child: SingleChildScrollView(
padding: EdgeInsets.only(
left: 20.0, right: 20.0, top: devicePadding.top + 150.0),
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
crossAxisAlignment: CrossAxisAlignment.center,
children: <Widget>[
Container(
decoration: BoxDecoration(
color: Colors.white,
borderRadius:
BorderRadius.all(Radius.circular(25.0))),
child: Padding(
padding: const EdgeInsets.all(30.0),
child: Form(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
crossAxisAlignment: CrossAxisAlignment.center,
children: <Widget>[
TrackingTextInput(
label: "Email",
hint: "What's your email address?",
onCaretMoved: (Offset caret) {
_teddyController.lookAt(caret);
}),
TrackingTextInput(
label: "Password",
hint: "Try 'bears'...",
isObscured: true,
onCaretMoved: (Offset caret) {
_teddyController.coverEyes(caret != null);
_teddyController.lookAt(null);
},
onTextChanged: (String value) {
_teddyController.setPassword(value);
},
),
SigninButton(
child: Text("Sign In",
style: TextStyle(
fontFamily: "RobotoMedium",
fontSize: 16,
color: Colors.white)),
onPressed: () {
_teddyController.submitPassword();
})
],
)),
)),
])),
),
],
)),
);
}
}
来源：https://stackoverflow.com/questions/62144264/flutter-flare-rive-is-it-able-to-use-for-background