94 lines
2.1 KiB
Dart
94 lines
2.1 KiB
Dart
library animated_visibility;
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import 'package:flutter/material.dart';
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enum FadeMode {
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vertical,
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horizontal,
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both,
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}
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class AnimatedVisibility extends StatefulWidget {
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final bool isVisible;
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final Duration duration;
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final Widget child;
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final Curve curve;
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final FadeMode fadeMode;
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const AnimatedVisibility({
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Key? key,
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required this.isVisible,
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required this.duration,
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required this.child,
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this.fadeMode = FadeMode.both,
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this.curve = Curves.easeIn,
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}) : super(key: key);
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@override
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_AnimatedVisibilityState createState() => _AnimatedVisibilityState();
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}
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class _AnimatedVisibilityState extends State<AnimatedVisibility>
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with SingleTickerProviderStateMixin {
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late final AnimationController _sizeController;
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late final Animation<double> _animation;
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@override
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void initState() {
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super.initState();
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_setupAnimation();
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_runSizeCheck(true);
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}
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void _setupAnimation() {
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_sizeController =
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AnimationController(vsync: this, duration: widget.duration);
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_animation = CurvedAnimation(
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parent: _sizeController,
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curve: widget.curve,
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);
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}
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@override
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void didUpdateWidget(covariant AnimatedVisibility oldWidget) {
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_runSizeCheck(false);
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super.didUpdateWidget(oldWidget);
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}
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void _runSizeCheck(bool isInit) async {
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if (widget.isVisible) {
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if (isInit) {
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_sizeController.value = 1;
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}
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_sizeController.forward();
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} else {
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_sizeController.reverse();
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}
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}
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@override
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void dispose() {
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_sizeController.dispose();
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super.dispose();
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}
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bool get _isVertical =>
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widget.fadeMode == FadeMode.vertical || widget.fadeMode == FadeMode.both;
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bool get _isHorizontal =>
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widget.fadeMode == FadeMode.horizontal ||
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widget.fadeMode == FadeMode.both;
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@override
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Widget build(BuildContext context) {
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return AnimatedBuilder(
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animation: _animation,
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child: widget.child,
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builder: (context, child) => Align(
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heightFactor: _isVertical ? _animation.value : null,
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widthFactor: _isHorizontal ? _animation.value : null,
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child: Opacity(opacity: _animation.value, child: child),
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),
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);
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}
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}
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