我如何最好地使用flutters的Java版本MethodChannel.invokeMenthod给出多个参数?

问题描述

我有一个flutter项目(插件)，该项目也使用一些本机Java代码.要在dart和Java之间进行通信，请使用MethodChannel.invokeMethod.这对于Java的dart来说非常有效，我可以在Java中使用call.argument("name")提取命名参数.但是，另一种方法让我有些头疼，因为我需要通过方法调用将可变数量的参数传递给dart，但是invokeMethod仅将"Object"作为参数.

I have a flutter project (plugin) that uses some native java code as well. To communicate between dart and java I use the MethodChannel.invokeMethod. This works very nicely from dart for java and I can pull out the named arguments with call.argument("name") in java. The other way is, however, giving me a bit of headache as I need to pass a variable number of arguments to dart with my method call, but invokeMethod only takes "Object" as an argument.

我已经看到它只适用于单个参数(例如字符串或整数)，但是我似乎找不到找到针对多个参数实现它的好方法.

I have seen it work with just the single argument like a string or int, but I cannot seem to find a good way to implement it for multiple arguments.

我本来希望可以将某种列表对象类型作为invokeMethod的参数传递，但是我无法在任何地方找到它.

I would have expected that there was some sort of list object type that I could pass as an argument for invokeMethod but I have not been able to find it anywhere.

任何人都可以提示如何做到最好吗?

Can any of you give a hint on how to best do this?

推荐答案

您必须将Map<String, dynamic>作为单个对象传递. (请注意，每个动态参数都必须是允许的数据类型.)这在Java端显示为HashMap. Java端有有用的getter函数来访问哈希映射成员.

You have to pass a Map<String, dynamic> as the single object. (Note that each of the dynamics must be one of the allowed data types.) This appears at the Java end as a HashMap. There are useful getter functions at the Java end to access the hash map members.

飞镖

  static void foo(String bar, bool baz) {
    _channel.invokeMethod('foo', <String, dynamic>{
      'bar': bar,
      'baz': baz,
    });
  }

Java

  String bar = call.argument("bar"); // .argument returns the correct type
  boolean baz = call.argument("baz"); // for the assignment

使用此，您可以实现相反的方向，例如:

Using this answer for the full outline, you can achieve the opposite direction like:

Java

  static void charlie(String alice, boolean bob) {
    HashMap<String, Object> arguments = new HashMap<>();
    arguments.put("alice", alice);
    arguments.put("bob", bob);
    channel.invokeMethod("charlie", arguments);
  }

飞镖

    String alice = methodCall.arguments['alice'];
    bool bob = methodCall.arguments['bob'];

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