Flutter 使用类在颤振中传递参数，如列表所示

我正在用flifter开发一个简单的聊天界面。有一个用户定义的小部件MessageBubble，它接受三个参数：发送方字符串、文本字符串和isMe bool。目前它正在一个接一个地传递静态值，如下所示：

List<MessageBubble> messages = [
    MessageBubble(
      sender: "Me",
      text: "Hi!",
      isMe: true,
    ),
    MessageBubble(
      sender: "Not Me",
      text: "Hey, hi!",
      isMe: false,
    ),
];

class BubbleData {
    List <String> sender = ['Not Me', 'Not Me'];
    List <String> text = ['Hey Hi', "What's new?"];
    List <bool> isMe = [false, false];
}

BubbleData data = BubbleData();  //instantiating

@override
Widget build(BuildContext context) {
  return Scaffold(
    body: ListView.builder(
      itemCount: data.sender.length,
      itemBuilder: (_, index) {
        return ListTile(
          title: Text(data.text[index]),         //iterating
          subtitle: Text(data.sender[index]),
        );
      },
    ),
  );
}

 class MyBubbleList extends StatelessWidget {

  final List<BubbleData> bubbles = [
   BubbleData(sender: 'Not Me', text: 'Hey Mi', isMe: false),
   BubbleData(sender: 'Not Me', text: 'What\'s new?', isMe: false)
];

  @override
  Widget build(BuildContext context) {

    //here the ListView part
    return ListView.builder(
      itemCount:bubbles.length,
      itemBuilder: (BuildContext context, int index) { 
             return Container(child:Text(bubbles[index].text));
      },);
  }
}

我想做的是创建一个类BubbleData，如下所示：

List<MessageBubble> messages = [
    MessageBubble(
      sender: "Me",
      text: "Hi!",
      isMe: true,
    ),
    MessageBubble(
      sender: "Not Me",
      text: "Hey, hi!",
      isMe: false,
    ),
];

class BubbleData {
    List <String> sender = ['Not Me', 'Not Me'];
    List <String> text = ['Hey Hi', "What's new?"];
    List <bool> isMe = [false, false];
}

BubbleData data = BubbleData();  //instantiating

@override
Widget build(BuildContext context) {
  return Scaffold(
    body: ListView.builder(
      itemCount: data.sender.length,
      itemBuilder: (_, index) {
        return ListTile(
          title: Text(data.text[index]),         //iterating
          subtitle: Text(data.sender[index]),
        );
      },
    ),
  );
}

 class MyBubbleList extends StatelessWidget {

  final List<BubbleData> bubbles = [
   BubbleData(sender: 'Not Me', text: 'Hey Mi', isMe: false),
   BubbleData(sender: 'Not Me', text: 'What\'s new?', isMe: false)
];

  @override
  Widget build(BuildContext context) {

    //here the ListView part
    return ListView.builder(
      itemCount:bubbles.length,
      itemBuilder: (BuildContext context, int index) { 
             return Container(child:Text(bubbles[index].text));
      },);
  }
}

---

现在面临的问题是，如何使用ListView生成器在MessageBubble中迭代这些listitems？

也许更好的方法是定义BubbleData，如下所示：

class BubbleData{
   String sender;
   String text;
   bool isMe;

   BubbleData({this.sender, this.text, this.isMe});
}

然后创建一个可以使用数据进行迭代的列表：

List<BubbleData> bubbles = [
   BubbleData(sender: 'Not Me', text: 'Hey Mi', isMe: false),
   BubbleData(sender: 'Not Me', text: 'What\'s new?', isMe: false)
];

下一步将映射并转换为MessageBubble的列表：

List<MessageBubble> messages = bubbles.map((bubble) =>
   MessageBubble(
      sender: bubble.sender, 
      text: bubble.text, 
      isMe: bubble.isMe
   )
).toList();

---

也许更好的方法是如下定义您的BubbleData：

class BubbleData{
   String sender;
   String text;
   bool isMe;

   BubbleData({this.sender, this.text, this.isMe});
}

然后创建一个可以使用数据进行迭代的列表：

List<BubbleData> bubbles = [
   BubbleData(sender: 'Not Me', text: 'Hey Mi', isMe: false),
   BubbleData(sender: 'Not Me', text: 'What\'s new?', isMe: false)
];

下一步将映射并转换为MessageBubble的列表：

List<MessageBubble> messages = bubbles.map((bubble) =>
   MessageBubble(
      sender: bubble.sender, 
      text: bubble.text, 
      isMe: bubble.isMe
   )
).toList();

---

您可以这样迭代：

List<MessageBubble> messages = [
    MessageBubble(
      sender: "Me",
      text: "Hi!",
      isMe: true,
    ),
    MessageBubble(
      sender: "Not Me",
      text: "Hey, hi!",
      isMe: false,
    ),
];

class BubbleData {
    List <String> sender = ['Not Me', 'Not Me'];
    List <String> text = ['Hey Hi', "What's new?"];
    List <bool> isMe = [false, false];
}

BubbleData data = BubbleData();  //instantiating

@override
Widget build(BuildContext context) {
  return Scaffold(
    body: ListView.builder(
      itemCount: data.sender.length,
      itemBuilder: (_, index) {
        return ListTile(
          title: Text(data.text[index]),         //iterating
          subtitle: Text(data.sender[index]),
        );
      },
    ),
  );
}

 class MyBubbleList extends StatelessWidget {

  final List<BubbleData> bubbles = [
   BubbleData(sender: 'Not Me', text: 'Hey Mi', isMe: false),
   BubbleData(sender: 'Not Me', text: 'What\'s new?', isMe: false)
];

  @override
  Widget build(BuildContext context) {

    //here the ListView part
    return ListView.builder(
      itemCount:bubbles.length,
      itemBuilder: (BuildContext context, int index) { 
             return Container(child:Text(bubbles[index].text));
      },);
  }
}

---

您可以这样迭代：

List<MessageBubble> messages = [
    MessageBubble(
      sender: "Me",
      text: "Hi!",
      isMe: true,
    ),
    MessageBubble(
      sender: "Not Me",
      text: "Hey, hi!",
      isMe: false,
    ),
];

class BubbleData {
    List <String> sender = ['Not Me', 'Not Me'];
    List <String> text = ['Hey Hi', "What's new?"];
    List <bool> isMe = [false, false];
}

BubbleData data = BubbleData();  //instantiating

@override
Widget build(BuildContext context) {
  return Scaffold(
    body: ListView.builder(
      itemCount: data.sender.length,
      itemBuilder: (_, index) {
        return ListTile(
          title: Text(data.text[index]),         //iterating
          subtitle: Text(data.sender[index]),
        );
      },
    ),
  );
}

 class MyBubbleList extends StatelessWidget {

  final List<BubbleData> bubbles = [
   BubbleData(sender: 'Not Me', text: 'Hey Mi', isMe: false),
   BubbleData(sender: 'Not Me', text: 'What\'s new?', isMe: false)
];

  @override
  Widget build(BuildContext context) {

    //here the ListView part
    return ListView.builder(
      itemCount:bubbles.length,
      itemBuilder: (BuildContext context, int index) { 
             return Container(child:Text(bubbles[index].text));
      },);
  }
}

---

按照阿卡德的回答。 您可以在如下列表视图中使用它：

List<MessageBubble> messages = [
    MessageBubble(
      sender: "Me",
      text: "Hi!",
      isMe: true,
    ),
    MessageBubble(
      sender: "Not Me",
      text: "Hey, hi!",
      isMe: false,
    ),
];

class BubbleData {
    List <String> sender = ['Not Me', 'Not Me'];
    List <String> text = ['Hey Hi', "What's new?"];
    List <bool> isMe = [false, false];
}

BubbleData data = BubbleData();  //instantiating

@override
Widget build(BuildContext context) {
  return Scaffold(
    body: ListView.builder(
      itemCount: data.sender.length,
      itemBuilder: (_, index) {
        return ListTile(
          title: Text(data.text[index]),         //iterating
          subtitle: Text(data.sender[index]),
        );
      },
    ),
  );
}

 class MyBubbleList extends StatelessWidget {

  final List<BubbleData> bubbles = [
   BubbleData(sender: 'Not Me', text: 'Hey Mi', isMe: false),
   BubbleData(sender: 'Not Me', text: 'What\'s new?', isMe: false)
];

  @override
  Widget build(BuildContext context) {

    //here the ListView part
    return ListView.builder(
      itemCount:bubbles.length,
      itemBuilder: (BuildContext context, int index) { 
             return Container(child:Text(bubbles[index].text));
      },);
  }
}

您可以在颤振文档中查看更多信息。您将发现关于如何使用ListView的非常好的视频教程。

---

希望它能帮助你理解Akade的答案。 您可以在如下列表视图中使用它：

List<MessageBubble> messages = [
    MessageBubble(
      sender: "Me",
      text: "Hi!",
      isMe: true,
    ),
    MessageBubble(
      sender: "Not Me",
      text: "Hey, hi!",
      isMe: false,
    ),
];

class BubbleData {
    List <String> sender = ['Not Me', 'Not Me'];
    List <String> text = ['Hey Hi', "What's new?"];
    List <bool> isMe = [false, false];
}

BubbleData data = BubbleData();  //instantiating

@override
Widget build(BuildContext context) {
  return Scaffold(
    body: ListView.builder(
      itemCount: data.sender.length,
      itemBuilder: (_, index) {
        return ListTile(
          title: Text(data.text[index]),         //iterating
          subtitle: Text(data.sender[index]),
        );
      },
    ),
  );
}

 class MyBubbleList extends StatelessWidget {

  final List<BubbleData> bubbles = [
   BubbleData(sender: 'Not Me', text: 'Hey Mi', isMe: false),
   BubbleData(sender: 'Not Me', text: 'What\'s new?', isMe: false)
];

  @override
  Widget build(BuildContext context) {

    //here the ListView part
    return ListView.builder(
      itemCount:bubbles.length,
      itemBuilder: (BuildContext context, int index) { 
             return Container(child:Text(bubbles[index].text));
      },);
  }
}

您可以在颤振文档中查看更多信息。您将发现关于如何使用ListView的非常好的视频教程。

---

希望对你有所帮助

我之所以在这里编辑你的文章，是因为我还面临一个问题。。。你能帮我吗？你的编辑被拒绝了，但是如果你愿意，我们可以在我编辑你的文章时讨论这个问题，因为我还面临一个问题。。。你能帮助我吗？你的编辑被拒绝了，但如果你愿意，我们可以讨论中的问题：如何通过ListView.builder迭代此消息？请告诉我如何在ListView.builder中使用列表消息？如何通过ListView.builder迭代此消息？请告诉我如何在ListView.builder中使用列表消息？这很有效。我没有返回文本，而是返回了一个MessageBubble，并传递了如下参数-sender:bubbles[index]。sender，Text:bubbles[index]。Text，isMe:bubbles[index]。isMeThis有效。我没有返回文本，而是返回了MessageBubble，并传递了如下参数-sender:bubbles[index]。sender，Text:bubbles[index]。Text，isMe:bubbles[index]。isMe