Sunday, March 11, 2018

android kotlin - Service example

MainActivity.kt 

package com.cfsuman.kotlinexamples

import android.support.v7.app.AppCompatActivity
import android.os.Bundle
import kotlinx.android.synthetic.main.activity_main.*
import android.app.ActivityManager
import android.content.Context
import android.widget.Toast
import android.content.Intent


class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        // Variable to hold service class name
        val serviceClass = RandomNumberService::class.java

        // Initialize a new Intent instance
        val intent = Intent(applicationContext, serviceClass)


        // Button to start the service
        button_start.setOnClickListener{
            // If the service is not running then start it
            if (!isServiceRunning(serviceClass)) {
                // Start the service
                startService(intent)
            } else {
                toast("Service already running.")
            }
        }


        // Button to stop the service
        button_stop.setOnClickListener{
            // If the service is not running then start it
            if (isServiceRunning(serviceClass)) {
                // Stop the service
                stopService(intent)
            } else {
                toast("Service already stopped.")
            }
        }


        // Get the service status
        button_stats.setOnClickListener{
            if (isServiceRunning(serviceClass)) {
                toast("Service is running.")
            } else {
                toast("Service is stopped.")
            }

        }
    }


    // Custom method to determine whether a service is running
    private fun isServiceRunning(serviceClass: Class<*>): Boolean {
        val activityManager = getSystemService(Context.ACTIVITY_SERVICE) as ActivityManager

        // Loop through the running services
        for (service in activityManager.getRunningServices(Integer.MAX_VALUE)) {
            if (serviceClass.name == service.service.className) {
                // If the service is running then return true
                return true
            }
        }
        return false
    }
}



// Extension function to show toast message
fun Context.toast(message:String){
    Toast.makeText(applicationContext,message,Toast.LENGTH_SHORT).show()
}
activity_main.xml 

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/root_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#7b917b"
    android:orientation="vertical"
    android:padding="16dp"
    >
    <Button
        android:id="@+id/button_start"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Start Service"
        />
    <Button
        android:id="@+id/button_stop"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Stop Service"
        />
    <Button
        android:id="@+id/button_stats"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Service Stats"
        />
</LinearLayout>
RandomNumberService.kt 

package com.cfsuman.kotlinexamples

import android.app.Service
import android.content.Intent
import android.os.Handler
import android.os.IBinder
import java.util.*


class RandomNumberService : Service() {

    private lateinit var mHandler: Handler
    private lateinit var mRunnable: Runnable

    override fun onBind(intent: Intent): IBinder? {
        throw UnsupportedOperationException("Not yet implemented")
    }

    override fun onStartCommand(intent: Intent, flags: Int, startId: Int): Int {
        // Send a notification that service is started
        toast("Service started.")

        // Do a periodic task
        mHandler = Handler()
        mRunnable = Runnable { showRandomNumber() }
        mHandler.postDelayed(mRunnable, 5000)

        return Service.START_STICKY
    }

    override fun onDestroy() {
        super.onDestroy()
        toast("Service destroyed.")
        mHandler.removeCallbacks(mRunnable)
    }

    // Custom method to do a task
    private fun showRandomNumber() {
        val rand = Random()
        val number = rand.nextInt(100)
        toast("Random Number : $number")
        mHandler.postDelayed(mRunnable, 5000)
    }
}
AndroidManifest.xml 

<?xml version="1.0" encoding="utf-8"?>
<manifest
    xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.cfsuman.kotlinexamples"
    >

    <uses-permission android:name="android.permission.INTERNET" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">

        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <service
            android:name=".RandomNumberService"
            android:enabled="true"
            android:exported="true"
            />
    </application>

</manifest>
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