Flutter实现直播间礼物收发

下面是一个简单的礼物发送系统的实现代码，包括支持连送和单次送等功能：

import 'package:flutter/material.dart';

class Gift {
  final String name;
  final int count;

  Gift(this.name, this.count);
}

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

  @override
  _GiftSendingScreenState createState() => _GiftSendingScreenState();
}

class _GiftSendingScreenState extends State<GiftSendingScreen> {
  List<Gift> _gifts = [
    Gift('Heart', 1),
    Gift('Rose', 1),
    Gift('Candy', 1),
    Gift('Teddy Bear', 5),
    Gift('Diamond Ring', 10),
  ];

  Gift? _selectedGift;
  int _sendingCount = 1;
  bool _isSendingContinuously = false;

  void _sendGift() {
    if (_selectedGift != null) {
      for (int i = 0; i < _sendingCount; i++) {
        // simulate sending gift to server
        print('Sending gift ${_selectedGift!.name}...');
      }

      if (_isSendingContinuously) {
        // continue sending gifts after a delay
        Future.delayed(Duration(seconds: 1), () {
          _sendGift();
        });
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Send Gift'),
      ),
      body: Column(
        crossAxisAlignment: CrossAxisAlignment.stretch,
        children: [
          DropdownButtonFormField<Gift>(
            decoration: InputDecoration(
              labelText: 'Select a gift',
            ),
            value: _selectedGift,
            onChanged: (gift) {
              setState(() {
                _selectedGift = gift;
              });
            },
            items: _gifts
                .map(
                  (gift) => DropdownMenuItem<Gift>(
                    value: gift,
                    child: Text('${gift.name} (${gift.count})'),
                  ),
                )
                .toList(),
          ),
          TextFormField(
            keyboardType: TextInputType.number,
            decoration: InputDecoration(
              labelText: 'Sending count',
            ),
            initialValue: '1',
            onChanged: (value) {
              setState(() {
                _sendingCount = int.tryParse(value) ?? 0;
              });
            },
          ),
          Row(
            children: [
              Checkbox(
                value: _isSendingContinuously,
                onChanged: (value) {
                  setState(() {
                    _isSendingContinuously = value ?? false;
                  });
                },
              ),
              Text('Send continuously'),
            ],
          ),
          ElevatedButton(
            onPressed: _sendGift,
            child: Text('Send'),
          ),
        ],
      ),
    );
  }
}

在这个示例中，我们使用了 Flutter 的 DropdownButtonFormField 和 TextFormField 等组件来获取用户选择的礼物和发送数量。我们还使用了 Checkbox 组件来允许用户选择是否连续发送礼物。在 _sendGift() 方法中，我们模拟将礼物发送到服务器，并且如果用户选择了连续发送，我们将延迟一秒钟后再次调用该方法以持续发送礼物。

以下是一个简单的收到礼物系统的实现代码，支持展示连送和单次送等数量：

import 'package:flutter/material.dart';

class ReceivedGift {
  final String name;
  final int count;

  ReceivedGift(this.name, this.count);
}

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

  @override
  _GiftReceivingScreenState createState() => _GiftReceivingScreenState();
}

class _GiftReceivingScreenState extends State<GiftReceivingScreen> {
  List<ReceivedGift> _receivedGifts = [];

  void _receiveGift(ReceivedGift gift) {
    setState(() {
      // check if the same gift is already received
      var existingGift = _receivedGifts.firstWhere(
        (g) => g.name == gift.name,
        orElse: () => null,
      );

      if (existingGift != null) {
        // increment count of existing gift
        _receivedGifts[_receivedGifts.indexOf(existingGift)] =
            ReceivedGift(gift.name, existingGift.count + gift.count);
      } else {
        // add new gift to received gifts list
        _receivedGifts.add(gift);
      }
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Received Gifts'),
      ),
      body: ListView.builder(
        itemCount: _receivedGifts.length,
        itemBuilder: (BuildContext context, int index) {
          var receivedGift = _receivedGifts[index];
          
          // build text based on number of gifts received
          var text = '${receivedGift.name} received';
          if (receivedGift.count > 1) {
            text += ' (${receivedGift.count}';
            text += receivedGift.count > 2 ? ' times)' : ' time)';
          }

          return ListTile(
            title: Text(text),
          );
        },
      ),
    );
  }
}

在这个示例中，我们使用了一个 _receivedGifts 列表来追踪用户收到的礼物。在 _receiveGift() 方法中，我们检查是否已经收到过相同的礼物，如果是，则增加现有礼物的数量；否则，将新礼物添加到列表中。

在 build() 方法中，我们使用 ListView.builder 来构建收到的礼物列表，并根据礼物数目构建展示文本。例如，如果用户收到多次相同礼物，则文本为“礼物名称接收（次数）”。