As next week will have importat launch for Rust 2018 and Flutter 1.0, I thought to build an app using Rust for the business logic and Flutter for the user interface, that can run at both Android and iOS, I built one and tested it at Android and it is working fine.
I just wonder how to measure the performance and compare it with native Android/iOS app.
The app flow is:
- Main is in Flutter, that is calling native function through platform_channel
- The native function is calling rust library through JNI (JNI wrapper is required to be call the rust library)
The structure is as below:
The code used is:
`main.dart:
import 'dart:async';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
final String title;
@override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
static const platform = const MethodChannel('samples.flutter.io/battery');
String _batteryLevel = 'Unknown battery level.';
Future<void> _getBatteryLevel() async {
String batteryLevel;
try {
final String hello = await platform.invokeMethod('getText');
final int result = await platform.invokeMethod('getBatteryLevel');
batteryLevel = '$hello Battery level at $result %.';
} on PlatformException catch (e) {
batteryLevel = "Failed to get battery level: '${e.message}'.";
}
setState(() {
_batteryLevel = batteryLevel;
});
}
@override
Widget build(BuildContext context) {
return Material(
child: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: [
RaisedButton(
child: Text('Get Battery Level'),
onPressed: _getBatteryLevel,
),
Text(_batteryLevel),
],
),
),
);
}
}
JNI wrapper - RustGreetings.kt
package com.mozilla.greetings
class RustGreetings {
companion object {
init {
System.loadLibrary("greetings")
}
}
private external fun greeting(pattern: String): String
fun sayHello(to: String): String = greeting(to)
}
And the Main Android activity is:
package com.example.batterylevel
import android.os.Bundle
import io.flutter.app.FlutterActivity
import io.flutter.plugins.GeneratedPluginRegistrant
import io.flutter.plugin.common.MethodChannel
import android.content.Context
import android.content.ContextWrapper
import android.content.Intent
import android.content.IntentFilter
import android.os.BatteryManager
import android.os.Build.VERSION
import android.os.Build.VERSION_CODES
import lib.Library
import com.mozilla.greetings.RustGreetings
class MainActivity: FlutterActivity() {
private val CHANNEL = "samples.flutter.io/battery"
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
GeneratedPluginRegistrant.registerWith(this)
MethodChannel(flutterView, CHANNEL).setMethodCallHandler { call, result ->
if (call.method == "getText") {
result.success(getText())
} else if (call.method == "getBatteryLevel") {
// result.success(getText())
val batteryLevel = getBatteryLevel()
if (batteryLevel != -1) {
result.success(batteryLevel)
} else {
result.error("UNAVAILABLE", "Battery level not available.", null)
}
}
else {
result.notImplemented()
}
}
}
private fun getBatteryLevel(): Int {
val batteryLevel: Int
if (VERSION.SDK_INT >= VERSION_CODES.LOLLIPOP) {
val batteryManager = getSystemService(Context.BATTERY_SERVICE) as BatteryManager
batteryLevel = batteryManager.getIntProperty(BatteryManager.BATTERY_PROPERTY_CAPACITY)
} else {
val intent = ContextWrapper(applicationContext).registerReceiver(null, IntentFilter(Intent.ACTION_BATTERY_CHANGED))
batteryLevel = intent!!.getIntExtra(BatteryManager.EXTRA_LEVEL, -1) * 100 / intent.getIntExtra(BatteryManager.EXTRA_SCALE, -1)
}
return batteryLevel
}
private fun getText(): String {
val x = Library().someLibraryMethod()
val g = RustGreetings()
val r = g.sayHello("My $x Rust")
return r
}
}
In the Android gradle.build I just added the below, as I'm interested to check also the impact of adding kotlin JVM library and getting it interacted with the Rust library within the mobile application:
dependencies {
implementation(files("src/main/libs/lib.jar"))
}
My question is:
How can check the performance and impact of each process when it is executed or called by another process
