YouTipFlutter Platform Channels
This section will introduce how to use Platform Channels to call native platform code in Flutter.
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## Platform Channel Overview
Platform Channels allow Dart code to communicate with native platforms (iOS/Android).
| Type | Description |
| --- | --- |
| MethodChannel | Method channel, used to call platform methods |
| EventChannel | Event channel, used for streaming data |
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## Dart Side Calling
## Example: MethodChannel Usage
import'package:flutter/services.dart';
// Define channel
class PlatformChannel {
static const MethodChannel _channel = MethodChannel('my_app/channel');
// Call native method - Get battery level
static Future getBatteryLevel() async {
try{
final int batteryLevel = await _channel.invokeMethod('getBatteryLevel');
return batteryLevel;
} on PlatformException catch(e){
print('Failed to get battery level: ${e.message}');
return-1;
}
}
// Call native method - Show Toast
static Future showToast(String message) async {
try{
await _channel.invokeMethod('showToast',{'message': message});
} on PlatformException catch(e){
print('Failed to show Toast: ${e.message}');
}
}
// Call native method - Get device information
static Future<Map> getDeviceInfo() async {
try{
final result = await _channel.invokeMapMethod('getDeviceInfo');
return result ??{};
} on PlatformException catch(e){
print('Failed to get device info: ${e.message}');
return{};
}
}
}
// Usage example
class MyWidget extends StatelessWidget {
const MyWidget({super.key});
@override
Widget build(BuildContext context){
return ElevatedButton(
onPressed:() async {
final battery = await PlatformChannel.getBatteryLevel();
print('Battery level: $battery%');
},
child:const Text('Get Battery Level'),
);
}
}
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## Android Side Implementation (Kotlin)
## Example: Android Side Code
// MainActivity.kt
package com.example.my_app
import android.os.Bundle
import io.flutter.embedding.android.FlutterActivity
import io.flutter.embedding.engine.FlutterEngine
import io.flutter.plugin.common.MethodChannel
class MainActivity : FlutterActivity() {
private val CHANNEL = "my_app/channel"
override fun configureFlutterEngine(flutterEngine: FlutterEngine) {
super.configureFlutterEngine(flutterEngine)
MethodChannel(flutterEngine.dartExecutor.binaryMessenger, CHANNEL)
.setMethodCallHandler { call, result ->
when (call.method) {
"getBatteryLevel" -> {
val batteryLevel = getBatteryLevel()
if (batteryLevel != -1) {
result.success(batteryLevel)
} else {
result.error("UNAVAILABLE", "Unable to get battery level", null)
}
}
"showToast" -> {
val message = call.argument("message")
showToast(message!!)
result.success(null)
}
else -> {
result.notImplemented()
}
}
}
}
private fun getBatteryLevel(): Int {
return try {
val batteryManager = getSystemService(BATTERY_SERVICE) as BatteryManager
batteryManager.getIntProperty(BatteryManager.BATTERY_PROPERTY_CAPACITY)
} catch (e: Exception) {
-1
}
}
private fun showToast(message: String) {
android.widget.Toast.makeText(this, message, android.widget.Toast.LENGTH_SHORT).show()
}
}
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## iOS Side Implementation (Swift)
## Example: iOS Side Code
// AppDelegate.swift
import Flutter
import UIKit
@UIApplicationMain
@objc class AppDelegate: FlutterAppDelegate {
private let CHANNEL = "my_app/channel"
override func application(
_ application: UIApplication,
didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
) -> Bool {
let controller = window?.rootViewController as! FlutterViewController
let channel = FlutterMethodChannel(
name: CHANNEL,
binaryMessenger: controller.binaryMessenger
)
channel.setMethodCallHandler { (call: FlutterMethodCall, result: @escaping FlutterResult) in
switch call.method {
case "getBatteryLevel":
self.getBatteryLevel(result: result)
case "showToast":
if let args = call.arguments as? [String: Any],
let message = args as? String {
self.showToast(message: message)
result(nil)
}
default:
result(FlutterMethodNotImplemented)
}
}
return super.application(application, didFinishLaunchingWithOptions: launchOptions)
}
private func getBatteryLevel(result: @escaping FlutterResult) {
UIDevice.current.isBatteryMonitoringEnabled = true
let batteryLevel = UIDevice.current.batteryLevel
if batteryLevel Platform Channels are the primary way for Flutter to communicate with native code, commonly used for calling system APIs, hardware functions, or using third-party native SDKs.