[移动开发]Flutter--自定义弹窗（含底部抽屉）Dialog

主要是基于系统的dialog机制做一些使用限制和自定义UI的优化

?

?

核心代码：

class CustomDialog {

  static void show(BuildContext context, Widget Function(BuildContext ctx, void Function() dismiss)builder, {bool cancellable = false}) {
    showDialog(
      context: context,
      barrierDismissible: cancellable,
      builder: (ctx) {
        return WillPopScope(
          child: Dialog(
            child: builder(ctx, () => Navigator.of(ctx).pop()),
            backgroundColor: Colors.transparent,
            shape: const RoundedRectangleBorder(borderRadius: BorderRadius.all(Radius.circular(0.0))),
            elevation: 0,
            alignment: Alignment.center,
          ),
          onWillPop: () async => cancellable,
        );
      },
    );
  }


  static void showBottomSheet(BuildContext context, Widget Function(BuildContext ctx, void Function() dismiss)builder, {bool cancellable = true}) {

    showModalBottomSheet(
      context: context,
      isDismissible: cancellable,
      enableDrag: cancellable,
      isScrollControlled: true,
      builder: (BuildContext ctx) {
        return WillPopScope(
          child: builder(ctx, () => Navigator.of(ctx).pop()),
          onWillPop: () async => cancellable,
        );
      },
      //不设置会默认使用屏幕最大宽度而不是子组件宽度
      constraints: const BoxConstraints(minWidth: 0, minHeight: 0, maxWidth: double.infinity, maxHeight: double.infinity),
      backgroundColor: Colors.transparent,
    );
  }
}

?使用：

import 'dart:async';
import 'package:flutter/material.dart';

class DialogTestPage extends StatefulWidget {
  const DialogTestPage({Key? key}) : super(key: key);

  @override
  State<StatefulWidget> createState() => _DialogTestState();
}

class _DialogTestState extends State<DialogTestPage> {
  @override
  Widget build(BuildContext context) {

    return Scaffold(
      body: Column(children: [
        const SizedBox(height: 0, width: double.infinity,),
        TextButton(
          child: const Text("show dialog"),
          onPressed: () => showCustomDialog(),
        ),
        TextButton(
          child: const Text("show delay dialog"),
          onPressed: () => showDelayDialog(),
        ),
        TextButton(
          child: const Text("show sheet"),
          onPressed: () => showSheetDialog(),
        ),
      ], mainAxisAlignment: MainAxisAlignment.spaceAround, crossAxisAlignment: CrossAxisAlignment.center,),
    );
  }


  void showCustomDialog() {
    CustomDialog.show(context, (context, dismiss) {
      return Container(
        width: 200,
        height: 100,
        color: Colors.white,
        child: Center(child: TextButton(onPressed: () => dismiss(), child: const Text("POP")),),
      );
    });
  }

  void showSheetDialog() {
    CustomDialog.showBottomSheet(context, (ctx, dismiss) {
      return Container(
        height: 300,
        color: Colors.white,
        child: Center(child: TextButton(onPressed: () => dismiss(), child: const Text("POP")),),
        margin: const EdgeInsets.all(20),
      );
    });
  }

  void showDelayDialog() {
    CustomDialog.show(context, (context, dismiss) {
      //延时关闭
      Timer(const Duration(seconds: 2), () => dismiss());

      return Container(
        width: 200,
        height: 100,
        color: Colors.yellow,
        child: const Center(child: Text("等待"),),
      );
    }, cancellable: true);
  }
}

其中show方法中使用到的Dialog默认使用material组件库的，如果觉得有不合理的尺寸约束，可替换我修改过的Dialog组件，有其他需求也可在此定制，为什么不直接放弃使用此组件？主要涉及到其路由跳转中的一些动画布局之类的。

class Dialog extends StatelessWidget {

  const Dialog({
    Key? key,
    this.backgroundColor,
    this.elevation,
    this.insetAnimationDuration = const Duration(milliseconds: 100),
    this.insetAnimationCurve = Curves.decelerate,
    this.insetPadding = const EdgeInsets.symmetric(horizontal: 40.0, vertical: 24.0),
    this.clipBehavior = Clip.none,
    this.shape,
    this.alignment,
    this.child,
  }) : super(key: key);


  final Color? backgroundColor;
  final double? elevation;
  final Duration insetAnimationDuration;
  final Curve insetAnimationCurve;
  final EdgeInsets? insetPadding;
  final Clip clipBehavior;
  final ShapeBorder? shape;
  final AlignmentGeometry? alignment;
  final Widget? child;

  static const RoundedRectangleBorder _defaultDialogShape =
  RoundedRectangleBorder(borderRadius: BorderRadius.all(Radius.circular(4.0)));
  static const double _defaultElevation = 24.0;

  @override
  Widget build(BuildContext context) {
    final DialogTheme dialogTheme = DialogTheme.of(context);
    final EdgeInsets effectivePadding = MediaQuery.of(context).viewInsets + (insetPadding ?? EdgeInsets.zero);
    return AnimatedPadding(
      padding: effectivePadding,
      duration: insetAnimationDuration,
      curve: insetAnimationCurve,
      child: MediaQuery.removeViewInsets(
        removeLeft: true,
        removeTop: true,
        removeRight: true,
        removeBottom: true,
        context: context,
        child: Align(
          alignment: alignment ?? dialogTheme.alignment ?? Alignment.center,
          child: Material(
            color: backgroundColor ?? dialogTheme.backgroundColor ?? Theme.of(context).dialogBackgroundColor,
            elevation: elevation ?? dialogTheme.elevation ?? _defaultElevation,
            shape: shape ?? dialogTheme.shape ?? _defaultDialogShape,
            type: MaterialType.card,
            clipBehavior: clipBehavior,
            child: child,
          ),
        ),
      ),
    );
  }
}