Nativescript use Android library - nativescript

Question

Could help me. I tried implement Android library in Nativescript.
I create Android Project -> New Module -> Andorid library.
Create Java Class
platforms\android\nativescript-serial-port\serialport\src\main\java\com\nativescript\serialport\Toaster.java
package com.nativescript.serialport;
import android.content.Context;
import android.widget.Toast;
public class Toaster {
public Toaster() {}
public void show(Context context) {
Toast.makeText(context, "Hello NativeScript!", Toast.LENGTH_SHORT).show();
}
}
Add in file nativescript project platforms\android\settings.gradle
include ':app', ':serialport'
project(':serialport').projectDir = new File('nativescript-serial-port/serialport')
Add in file nativescript app app\App_Resources\Android\app.gradle
dependencies {
implementation project(":serialport")
}
Add in JS file nativescript project some-file.js
import * as app from 'application';
const context = android.content.Context;
const toaster = new com.nativescript.serialport.Toaster();
toaster.show(context);
And if I run this code appear error
System.err: TypeError: com.nativescript.serialport.Toaster is not a constructor
System.err: File: "file:///data/data/org.nativescript.application/files/app/bundle.js,
line: 372, column: 22
System.err:
System.err: StackTrace:
System.err: Frame: function:'onPrint', file:'file:///data/data/org.nativescript.application/files/app/bundle.js',
line: 372, column: 23
System.err: Frame: function:'invoker', file:'file:///data/data/org.nativescript.application/files/app/vendor.js',
line: 4168, column: 18
System.err: Frame: function:'Observable.notify', file:'file:///data/data/org.nativescript.application/files/app/vendor.js',
line: 17698, column: 15
System.err: Frame: function:'Observable._emit', file:'file:///data/data/org.nativescript.application/files/app/vendor.js',
line: 17726, column: 12
System.err: Frame: function:'ClickListenerImpl.onClick', file:'file:///data/data/org.nativescript.application/files/app/vendor.js',
line: 29193, column: 15
System.err:
System.err: at com.tns.Runtime.callJSMethodNative(Native Method)
System.err: at com.tns.Runtime.dispatchCallJSMethodNative(Runtime.java:1120)
System.err: at com.tns.Runtime.callJSMethodImpl(Runtime.java:1000)
System.err: at com.tns.Runtime.callJSMethod(Runtime.java:987)
System.err: at com.tns.Runtime.callJSMethod(Runtime.java:967)
System.err: at com.tns.Runtime.callJSMethod(Runtime.java:959)
System.err: at com.tns.gen.java.lang.Object_vendor_29183_26_ClickListenerImpl.onClick(Object_vendor_29183_26_ClickListenerImpl.java:17)
System.err: at android.view.View.performClick(View.java:6597)
System.err: at android.view.View.performClickInternal(View.java:6574)
System.err: at android.view.View.access$3100(View.java:778)
System.err: at android.view.View$PerformClick.run(View.java:25885)
System.err: at android.os.Handler.h
andleCallback(Handler.java:873) System.err: at
android.os.Handler.dispatchMessage(Handler.java:99) System.err: at
android.os.Looper.loop(Looper.java:193) System.err: at
android.app.ActivityThread.main(ActivityThread.java:6669) System.err:
at java.lang.reflect.Method.invoke(Native Method) System.err: at
com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
System.err: at
com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
How fix this error. Thanks