由于下周将有 Rust 2018 和 Flutter 1.0 的重要发布,我想构建一个应用程序,使用 Rust 进行业务逻辑,使用 Flutter 进行用户界面,可以在 Android 和 iOS 上运行,我构建了一个并进行了测试它在 Android 上运行良好。
我只是想知道如何衡量性能并将其与原生 Android/iOS 应用程序进行比较。
应用程序流程是:
- Main在Flutter中,即通过platform_channel调用原生函数
- 原生函数通过JNI调用rust库(需要JNI包装器来调用rust库)
结构如下:
使用的代码是:
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 包装器 - 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)
}
主要的 Android Activity 是:
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
}
}
在 Android gradle.build
中,我刚刚添加了以下内容,因为我也有兴趣检查添加 kotlin JVM 库并使其与移动应用程序中的 Rust 库交互的影响:
dependencies {
implementation(files("src/main/libs/lib.jar"))
}
我的问题是: 如何检查每个进程被另一个进程执行或调用时的性能和影响
最佳答案
随着ffi的介绍在 Dart 中,事情变得更加流畅,性能更好,因为现在直接交互是 Dart/Rust,不需要 Dart/Kotlin/Rust 或 Dart/Swift/Rust 循环,下面是一个简单的示例:
第一个src/lib.rs
#[no_mangle]
pub extern fn rust_fn(x: i32) -> i32 {
println!("Hello from rust\nI'll return: {}", x.pow(2));
x.pow(2)
}
和Cargo.toml
[package]
name = "Double_in_Rost"
version = "0.1.0"
authors = ["Hasan Yousef"]
edition = "2018"
[lib]
name = "rust_lib"
crate-type = ["dylib"] # could be `staticlib` as well
[dependencies]
运行 cargo build --release
将生成 target\release\rust_lib.dll
将其复制/粘贴到 Dart 应用程序根目录
编写 Dart 代码如下:
import 'dart:ffi';
import 'dart:io' show Platform;
// FFI signature of the hello_world C function
typedef ffi_func = Int32 Function(Int32 x); //pub extern fn rust_fn(x: i32) -> i32
// Dart type definition for calling the C foreign function
typedef dart_func = int Function(int x);
void main() {
// Open the dynamic library
var path = './rust_lib.so';
if (Platform.isMacOS) path = './rust_lib.dylib';
if (Platform.isWindows) path = 'rust_lib.dll';
final dylib = DynamicLibrary.open(path);
// Look up the Rust/C function
final my_func =
dylib.lookup<NativeFunction<ffi_func>>('rust_fn').asFunction<dart_func>();
print('Double of 3 is ${my_func(3)}');
}
关于android - 为移动应用程序集成 Rust + Flutter + Kotlin,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/53532964/