Request location updates

Details
Written by: Stanko Milosev
Category: Android
Hits: 1103
Here I gave one example on how to get GPS location, problem with that solution is that location will be calculated once, and not any more, if you need like every few seconds to receive location, this solution will give you same location all the time.

Here is another example to receive updated location.
First I have added fusedLocationClient as private member variable: 

private lateinit var fusedLocationClient: FusedLocationProviderClient
Where FusedLocationProviderClient is imported from: 
implementation 'com.google.android.gms:play-services-location:19.0.1'
In onCreate I have initialized fusedLocationClient: 
override fun onCreate(savedInstanceState: Bundle?) {
	super.onCreate(savedInstanceState)
	setContentView(R.layout.activity_main)
	fusedLocationClient = LocationServices.getFusedLocationProviderClient(this)        
}
I need line like 
fusedLocationClient.requestLocationUpdates(locationRequest, locationCallback, Looper.getMainLooper())
For that I need locationRequest and locationCallback
Both locationRequest and locationCallback I have declared as member variables: 
private lateinit var locationCallback: LocationCallback
private lateinit var locationRequest: LocationRequest
locationRequest: 
locationRequest = LocationRequest.create().apply {
	interval = 5000
	fastestInterval = 50000
	smallestDisplacement = 170f // 170 m = 0.1 mile
	priority = LocationRequest.PRIORITY_HIGH_ACCURACY
}
locationCallback: 
locationCallback = object : LocationCallback() {
	override fun onLocationResult(locationResult: LocationResult) {
		locationResult ?: return

		if (locationResult.locations.isNotEmpty()) {
			// get latest location
			val location =
				locationResult.lastLocation
			if (location != null) {
				println(location.latitude.toString())
				println(location.longitude.toString())
			}
		}
	}
}
In app\src\main\AndroidManifest.xml I have added permissions: 
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
And check for permission: 
if (ActivityCompat.checkSelfPermission(
		this,
		Manifest.permission.ACCESS_FINE_LOCATION
	) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(
		this,
		Manifest.permission.ACCESS_COARSE_LOCATION
	) != PackageManager.PERMISSION_GRANTED
) {
	if (ActivityCompat.shouldShowRequestPermissionRationale(
			this as Activity,
			Manifest.permission.ACCESS_FINE_LOCATION
		)
	) {
		return
	} else {
		ActivityCompat.requestPermissions(
			this,
			arrayOf(
				Manifest.permission.ACCESS_FINE_LOCATION,
			)
			, 99
		)
	}
}
At the end my MainActivity.kt looks like: 
package com.milosev.requestlocationupdates

import android.Manifest
import android.app.Activity
import android.content.pm.PackageManager
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.os.Looper
import android.view.View
import androidx.core.app.ActivityCompat
import com.google.android.gms.location.*

class MainActivity : AppCompatActivity() {
    private lateinit var fusedLocationClient: FusedLocationProviderClient
    private lateinit var locationCallback: LocationCallback
    private lateinit var locationRequest: LocationRequest

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        fusedLocationClient = LocationServices.getFusedLocationProviderClient(this)
    }

    fun requestLocationUpdatesClick(view: View) {

        if (ActivityCompat.checkSelfPermission(
                this,
                Manifest.permission.ACCESS_FINE_LOCATION
            ) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(
                this,
                Manifest.permission.ACCESS_COARSE_LOCATION
            ) != PackageManager.PERMISSION_GRANTED
        ) {
            if (ActivityCompat.shouldShowRequestPermissionRationale(
                    this as Activity,
                    Manifest.permission.ACCESS_FINE_LOCATION
                )
            ) {
                return
            } else {
                ActivityCompat.requestPermissions(
                    this,
                    arrayOf(
                        Manifest.permission.ACCESS_FINE_LOCATION,
                    )
                    , 99
                )
            }
        }

        locationRequest = LocationRequest.create().apply {
            interval = 5000
            fastestInterval = 50000
            smallestDisplacement = 170f // 170 m = 0.1 mile
            priority = LocationRequest.PRIORITY_HIGH_ACCURACY
        }

        locationCallback = object : LocationCallback() {
            override fun onLocationResult(locationResult: LocationResult) {
                locationResult ?: return

                if (locationResult.locations.isNotEmpty()) {
                    // get latest location
                    val location =
                        locationResult.lastLocation
                    if (location != null) {
                        println(location.latitude.toString())
                        println(location.longitude.toString())
                    }
                }
            }
        }

        fusedLocationClient.requestLocationUpdates(locationRequest, locationCallback,
            Looper.getMainLooper())
    }
}

Write file on internal storage

Details
Written by: Stanko Milosev
Category: Android
Hits: 1065
Method to write file: 
private fun writeFileOnInternalStorage(mcoContext: Context, sFileName: String?, sBody: String?) {
	val dir = File(mcoContext.getFilesDir(), "mydir")
	if (!dir.exists()) {
		dir.mkdir()
	}
	try {
		val gpxfile = File(dir, sFileName)
		val writer = FileWriter(gpxfile)
		writer.append(sBody)
		writer.flush()
		writer.close()
	} catch (e: Exception) {
		e.printStackTrace()
	}
}

Small example on how to get gps Location

Details
Written by: Stanko Milosev
Category: Android
Hits: 1401
Start empty activity like I already explained here.

In order to display design window, locate activity_main.xml, you will find it under Project -> app -> src -> main -> res -> layout:

Open it and add a button:

In activity_main.xml I have added android:onClick="getGps" so my activity_main.xml looks like: 

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Button"
        android:onClick="getGps"
        tools:layout_editor_absoluteX="166dp"
        tools:layout_editor_absoluteY="441dp" />

</androidx.constraintlayout.widget.ConstraintLayout>
In build.gradle as I already explained here I have added Google Play services com.google.android.gms.location like this: 
implementation 'com.google.android.gms:play-services-location:19.0.1'
Now my build.gradle looks like: 
plugins {
    id 'com.android.application'
    id 'org.jetbrains.kotlin.android'
}

android {
    compileSdk 32

    defaultConfig {
        applicationId "com.milosev.getgpslocation"
        minSdk 21
        targetSdk 32
        versionCode 1
        versionName "1.0"

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
    kotlinOptions {
        jvmTarget = '1.8'
    }
}

dependencies {

    implementation 'androidx.core:core-ktx:1.7.0'
    implementation 'androidx.appcompat:appcompat:1.4.1'
    implementation 'com.google.android.material:material:1.5.0'
    implementation 'androidx.constraintlayout:constraintlayout:2.1.3'
    implementation 'com.google.android.gms:play-services-location:19.0.1'
    testImplementation 'junit:junit:4.13.2'
    androidTestImplementation 'androidx.test.ext:junit:1.1.3'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
}
In Android -> app -> manifests -> AndroidManifest.xml I added permissions like: 
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

In order to request permission I In Project -> app -> src -> main -> java -> com -> milosev -> getgpslocation -> MainActivity.kt I wrote: 

if (ActivityCompat.checkSelfPermission(
		this,
		Manifest.permission.ACCESS_FINE_LOCATION
	) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(
		this,
		Manifest.permission.ACCESS_COARSE_LOCATION
	) != PackageManager.PERMISSION_GRANTED
) {
	if (ActivityCompat.shouldShowRequestPermissionRationale(
			this,
			Manifest.permission.ACCESS_FINE_LOCATION
		)
	) {
		return
	} else {
		// No explanation needed, we can request the permission.
		requestLocationPermission()
	}
}
So my whole MainActivity.kt looks like: 
package com.milosev.getgpslocation

import android.Manifest
import android.content.pm.PackageManager
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.view.View
import androidx.core.app.ActivityCompat
import com.google.android.gms.location.FusedLocationProviderClient
import com.google.android.gms.location.LocationServices

class MainActivity : AppCompatActivity() {
    private lateinit var fusedLocationClient: FusedLocationProviderClient

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        fusedLocationClient = LocationServices.getFusedLocationProviderClient(this)
    }

    fun getGps(view: View) {
        if (ActivityCompat.checkSelfPermission(
                this,
                Manifest.permission.ACCESS_FINE_LOCATION
            ) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(
                this,
                Manifest.permission.ACCESS_COARSE_LOCATION
            ) != PackageManager.PERMISSION_GRANTED
        ) {
            if (ActivityCompat.shouldShowRequestPermissionRationale(
                    this,
                    Manifest.permission.ACCESS_FINE_LOCATION
                )
            ) {
                return
            } else {
                // No explanation needed, we can request the permission.
                requestLocationPermission()
            }
        }
        fusedLocationClient.lastLocation
            .addOnSuccessListener { location->
                if (location != null) {
                    // use your location object
                    // get latitude , longitude and other info from this
                }

            }
    }

    private fun requestLocationPermission() {
        ActivityCompat.requestPermissions(
            this,
            arrayOf(
                Manifest.permission.ACCESS_FINE_LOCATION,
            ),
            MY_PERMISSIONS_REQUEST_LOCATION
        )
    }

    companion object {
        private const val MY_PERMISSIONS_REQUEST_LOCATION = 99
        private const val MY_PERMISSIONS_REQUEST_BACKGROUND_LOCATION = 66
    }

}
With piece of code: 
fusedLocationClient.lastLocation
.addOnSuccessListener { location->
	if (location != null) {
		// use your location object
		// get latitude , longitude and other info from this
	}
I am actually geting the location.

Create Json With Gson

Details
Written by: Stanko Milosev
Category: Android
Hits: 1533
Example how to start new Empty activity, add library to Gradle, and create JSON with GSON.

First start "Empty Activity":

In next step in my case I have choosen language Kotlin, Minimum SDK API 21:

In Android -> Gradle Scripts -> build.gradle:

I have added: 

    implementation 'com.google.code.gson:gson:2.9.0'
Now my dependecies look like: 
dependencies {
    implementation 'androidx.core:core-ktx:1.7.0'
    implementation 'androidx.appcompat:appcompat:1.4.1'
    implementation 'com.google.android.material:material:1.5.0'
    implementation 'androidx.constraintlayout:constraintlayout:2.1.3'
    testImplementation 'junit:junit:4.13.2'
    androidTestImplementation 'androidx.test.ext:junit:1.1.3'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
    implementation 'com.google.code.gson:gson:2.9.0'
}
Go to File -> Sync Project with Gradle Files:

In MainActivity write something like: 

internal class Albums {
    var title: String? = null
    var message: String? = null
    var errors = arrayOf<String>()
    var total: String? = null
    var total_pages = 0
    var page = 0
    var limit: String? = null
}
and 
val albums = Albums()
albums.title = "Free Music Archive - Albums"
albums.message = ""
albums.total = "11259"
albums.total_pages = 2252
albums.page = 1
albums.limit = "5"

val builder = GsonBuilder()
val gson: Gson = builder.create()
System.out.println(gson.toJson(albums))
My MainActivity now looks like: 
package com.example.myapplication

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import com.google.gson.Gson
import com.google.gson.GsonBuilder

internal class Albums {
    var title: String? = null
    var message: String? = null
    var errors = arrayOf<String>()
    var total: String? = null
    var total_pages = 0
    var page = 0
    var limit: String? = null
}

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

        val albums = Albums()
        albums.title = "Free Music Archive - Albums"
        albums.message = ""
        albums.total = "11259"
        albums.total_pages = 2252
        albums.page = 1
        albums.limit = "5"

        val builder = GsonBuilder()
        val gson: Gson = builder.create()
        System.out.println(gson.toJson(albums))
    }
}
  1. New and improved my list of best applications
  2. New line
  3. Command line building and installing - gradle and adb
  4. Border around controls

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