Nova tela de login | Adaptaçao nova da AppBar | Animções novas

lib/widgets/entrance.dart

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+import 'package:flutter/material.dart';
+
+/// Animação de entrada (fade + leve deslize para cima) para dar vida a
+/// cards e listas quando aparecem em ecrã. Suporta [delay] para permitir
+/// efeito "staggered" (itens surgindo em sequência) em listas/grades.
+class FadeSlideIn extends StatefulWidget {
+  const FadeSlideIn({
+    super.key,
+    required this.child,
+    this.delay = Duration.zero,
+    this.duration = const Duration(milliseconds: 420),
+    this.offset = const Offset(0, 0.08),
+  });
+
+  final Widget child;
+  final Duration delay;
+  final Duration duration;
+  final Offset offset;
+
+  @override
+  State<FadeSlideIn> createState() => _FadeSlideInState();
+}
+
+class _FadeSlideInState extends State<FadeSlideIn>
+    with SingleTickerProviderStateMixin {
+  late final AnimationController _controller = AnimationController(
+    vsync: this,
+    duration: widget.duration,
+  );
+  late final Animation<double> _fade = CurvedAnimation(
+    parent: _controller,
+    curve: Curves.easeOut,
+  );
+  late final Animation<Offset> _slide = Tween<Offset>(
+    begin: widget.offset,
+    end: Offset.zero,
+  ).animate(CurvedAnimation(parent: _controller, curve: Curves.easeOutCubic));
+
+  @override
+  void initState() {
+    super.initState();
+    if (widget.delay == Duration.zero) {
+      _controller.forward();
+    } else {
+      Future.delayed(widget.delay, () {
+        if (mounted) _controller.forward();
+      });
+    }
+  }
+
+  @override
+  void dispose() {
+    _controller.dispose();
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return FadeTransition(
+      opacity: _fade,
+      child: SlideTransition(position: _slide, child: widget.child),
+    );
+  }
+}