Account
Sign in to you account
Sign In Sign Up

How to Invoke Dart Code From Kotlin Code?

6 minutes read

To invoke Dart code from Kotlin code, you can use platform channels provided by Flutter. The platform channel allows you to pass messages between Dart and platform-specific code, such as Kotlin or Java in Android.


To invoke Dart code from Kotlin code, first create a method in your Dart code that you want to call from Kotlin. Then, create a MethodChannel object in Kotlin, specifying the channel name matching the one in Dart. Finally, call the invokeMethod method on the MethodChannel object.


In Dart code:

  1. Create a method that you want to call from Kotlin code, for example:
1
2
3
4

// Method in Dart code
void myMethod() {
  print("Invoked from Kotlin code");
}


In Kotlin code:

  1. Create a MethodChannel object with the channel name matching the one in Dart:
1

val methodChannel = MethodChannel(flutterEngine.dartExecutor.binaryMessenger, "my_channel_name")


  1. Call the invokeMethod method on the MethodChannel object to invoke the Dart method:
1

methodChannel.invokeMethod("myMethod")


By following these steps, you can successfully invoke Dart code from Kotlin code using platform channels in Flutter.


What is the best practice for invoking dart code from kotlin?

The best practice for invoking Dart code from Kotlin is to use platform channels. Platform channels allow communication between Dart and native platform code, such as Kotlin in this case.


To invoke Dart code from Kotlin using platform channels, you need to create a MethodChannel object in Kotlin and specify the channel name that corresponds to the channel name in the Dart code. Then, you can use the invokeMethod function on the MethodChannel object to call methods in Dart code and pass parameters as needed.


Here is an example of invoking Dart code from Kotlin using platform channels:


In your Dart code:

1
2
3
4
5
6
7
8

// Define a MethodChannel
final MethodChannel channel = MethodChannel('your_channel_name');
// Register a method to handle the invocation from Kotlin
channel.setMethodCallHandler((call) async {
  if (call.method == 'your_method_name') {
    // Do something in Dart code
  }
});


In your Kotlin code:

1
2
3
4

// Create a MethodChannel object
val channel = MethodChannel(flutterEngine.dartExecutor.binaryMessenger, "your_channel_name")
// Invoke a method in Dart code
channel.invokeMethod("your_method_name", parameters) // parameters is an optional argument


By following this best practice of using platform channels, you can easily invoke Dart code from Kotlin and ensure smooth communication between the two languages.


What is the process for receiving results from dart code in kotlin?

To receive results from Dart code in Kotlin, you can use platform channels. Here is a step-by-step process to achieve this:

  1. Define a method in Dart code that you want to call from Kotlin code and which will return the result. For example, let's say you have a method in Dart called getResult() which returns a string.
1
2
3
4
5

class MyDartClass {
  static String getResult() {
    return "This is the result from Dart code";
  }
}


  1. Set up method channel in Dart to communicate with Kotlin code.
 1
 2
 3
 4
 5
 6
 7
 8
 9
10

import 'package:flutter/services.dart';

MethodChannel _channel = MethodChannel('com.example.my_flutter_app/result');

_channel.setMethodCallHandler((call) async {
  if (call.method == 'getResult') {
    return MyDartClass.getResult();
  }
  return null;
});


  1. In your Kotlin code, set up a method to call the Dart method and receive the result.
1
2
3

val channel = MethodChannel(flutterEngine.dartExecutor.binaryMessenger, "com.example.my_flutter_app/result")

val result = channel.invokeMethod("getResult") as String


Now, when you call the getResult() method from Kotlin code, it will communicate with the Dart code through the method channel and return the result back to Kotlin.


How do I pass parameters to dart functions from kotlin?

To pass parameters to Dart functions from Kotlin, you can use the invokeMethod method provided by the Flutter plugin. Here is an example of how you can achieve this:

  1. Create a Dart function that accepts parameters:
1
2
3
4

void myDartFunction(String param1, int param2) {
  print('Parameter 1: $param1');
  print('Parameter 2: $param2');
}


  1. In your Kotlin code, you can call this Dart function and pass parameters using the invokeMethod method like this:
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12

class MyActivity : FlutterActivity() {

  override fun onCreate(savedInstanceState: Bundle?) {
     super.onCreate(savedInstanceState)
    
     MethodChannel(flutterView, "myChannel")
        .invokeMethod("myDartFunction", hashMapOf(
           "param1" to "Hello",
           "param2" to 123
        ))
  }
}


  1. In this example, we are invoking the myDartFunction from the Kotlin code and passing the parameters "Hello" and 123 to it. The myChannel is the name of the channel that you have set up in your Dart code to communicate between Kotlin and Dart.


By following these steps, you can easily pass parameters to Dart functions from your Kotlin code in a Flutter application.


How can I execute dart methods in a kotlin project?

To execute Dart methods in a Kotlin project, you can use the platform channel to communicate between Dart and Kotlin. Here's a general outline of how you can achieve this:

  1. Create a Flutter project with the Dart methods that you want to execute in your Kotlin project.
  2. Add platform-specific code for Android in the android directory of your Flutter project.
  3. Create a MethodChannel in your Dart code to establish communication between Dart and Kotlin.
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13

import 'package:flutter/services.dart';

class PlatformMethodChannel {
  static const platform = MethodChannel('example/platform_channel');

  static Future<void> executeMethod(String methodName) async {
    try {
      await platform.invokeMethod(methodName);
    } on PlatformException catch (e) {
      print("Failed to execute method: '${e.message}'.");
    }
  }
}


  1. In your Kotlin project, create a Kotlin class that implements MethodCallHandler. This class will receive method calls from Dart and execute the corresponding code.
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18

import io.flutter.plugin.common.MethodCall
import io.flutter.plugin.common.MethodChannel
import io.flutter.plugin.common.MethodChannel.MethodCallHandler
import io.flutter.plugin.common.MethodChannel.Result

class PlatformMethodChannel : MethodCallHandler {
    override fun onMethodCall(call: MethodCall, result: Result) {
        when (call.method) {
            "methodName" -> {
                // Execute the corresponding method in Kotlin
                result.success(null)
            }
            else -> {
                result.notImplemented()
            }
        }
    }
}


  1. Register the method channel in the init method of your Flutter activity.
1
2

MethodChannel(flutterEngine.dartExecutor.binaryMessenger, "example/platform_channel")
        .setMethodCallHandler(PlatformMethodChannel())


  1. Finally, you can call the Dart methods in your Kotlin project using the PlatformMethodChannel.executeMethod() method.
1

PlatformMethodChannel.executeMethod("methodName")


By following these steps, you can successfully execute Dart methods in your Kotlin project using the platform channel.


How to exchange messages between dart and kotlin code?

There are several ways to exchange messages between Dart and Kotlin code:

  1. Platform Channels: Dart and Kotlin code can communicate with each other through platform channels using the Flutter framework. This allows you to send and receive messages between the two languages by calling platform-specific methods. You can use MethodChannel on the Dart side and Channel on the Kotlin side to establish communication between the two.
  2. REST API: You can use REST APIs to exchange messages between Dart and Kotlin code. Both languages can make HTTP requests to a server where the data is exchanged. The server can act as an intermediary for communication between the Dart and Kotlin code.
  3. WebSocket: WebSocket is a communication protocol that provides full-duplex communication channels over a single TCP connection. You can establish a WebSocket connection between Dart and Kotlin code to exchange messages in real-time.
  4. Shared Preferences: Shared preferences can be used to store and retrieve data in key-value pairs. Shared preferences can be accessed by both Dart and Kotlin code, allowing you to exchange messages by storing data in shared preferences.
  5. Local Database: You can use local databases such as SQLite or Room in Kotlin and SQFlite in Dart to store and retrieve data. Both languages can access the database to exchange messages between each other.


Overall, platform channels and REST APIs are popular methods for exchanging messages between Dart and Kotlin code due to their flexibility and ease of implementation.

Facebook Twitter LinkedIn Telegram

Related Posts:

How to Access Object Class From Kotlin In Java?
To access an object class from Kotlin in Java, you can follow these steps:Create a Kotlin class that you want to access in Java.Make sure the Kotlin class is marked with the @JvmName annotation with a custom name to be used in Java code.Compile the Kotlin code...
How to Make Intersect Of Multiple Lists In Kotlin?
To make an intersect of multiple lists in Kotlin, you can use the intersect function available in Kotlin&#39;s standard library. This function takes multiple lists as parameters and returns a new list containing only the elements that are present in all of the...
How to Make A Open Class to Sealed Class In Kotlin?
To make an open class into a sealed class in Kotlin, you simply need to replace the &#34;open&#34; keyword with the &#34;sealed&#34; keyword in the class definition. This will restrict the inheritance of the class so that it can only be subclassed within the s...
How to Fetch Json Array In Android Kotlin?
To fetch a JSON array in Android Kotlin, you can use the JSONObject and JSONArray classes provided by the Android SDK. First, you need to make an HTTP request to the server that provides the JSON data. You can use libraries like Retrofit or Volley for this pur...
How to Detect Volume Change In Kotlin?
To detect volume change in Kotlin, you can use the AudioManager class provided by the Android framework. This class allows you to monitor changes in volume levels for different audio streams such as music, notifications, and alarms. You can register a Broadcas...