Zgłosiłam się do udziału w bootcampie androidowym. Warunkiem wzięcia udziału było napisanie dwóch aplikacji do końca sierpnia. Niestety końcówkę sierpnia spędziłam z Małym w szpitalu, więc się nie załapałam, ale coś tam z tej aplikacji powstało 😉 Nie chcę żeby się zmarnowało, więc dokończyłam implementację i będę mieć do portfolio ;D
Mały w żłobku, więc zaczynamy 🙂
Jedna z aplikacji, które były wymagane miała używać GPS-a i pozwalać na zapisywanie położenia w „sposób trwały”. Dodatkowo mogła też wyświetlać je na mapie. Stworzyłam sobie taką aplikację w Kotlinie. I tak bardziej wygląda to na koślawą aplikację javową, ale może jeszcze kiedyś do niej usiądę i będzie bardziej kotlinowa 😉 cały kod -> tu
Troszkę kodu? proszę 😉
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| package com.projects.jezinka.myplaces | |
| import android.provider.BaseColumns | |
| object MyPlacesContract { | |
| data class MyPlace(val id: Long, | |
| val longitude: String, | |
| val latitude: String, | |
| val note: String, | |
| val order: Int) | |
| class MyPlaceEntry : BaseColumns { | |
| companion object { | |
| val TABLE_NAME = "my_place" | |
| val _ID = "_id" | |
| val COLUMN_NAME_LONGITUDE = "longitude" | |
| val COLUMN_NAME_LATITUDE = "latitude" | |
| val COLUMN_NAME_NOTE = "note" | |
| val COLUMN_NAME_ORDER = "order_no" | |
| } | |
| } | |
| } |
Kotlin nie oferuje statycznych obiektów, właściwości, etc. Zamiast tego mamy tzw. companion object, którego możemy użyć w odwołaniach:
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| package com.projects.jezinka.myplaces | |
| import android.content.Context | |
| import android.database.sqlite.SQLiteDatabase | |
| import android.database.sqlite.SQLiteOpenHelper | |
| class MyPlacesDBHelper(context: Context) : SQLiteOpenHelper(context, DATABASE_NAME, null, DATABASE_VERSION) { | |
| private val SQL_CREATE_ENTRIES = | |
| """CREATE TABLE ${MyPlacesContract.MyPlaceEntry.Companion.TABLE_NAME} | |
| (${MyPlacesContract.MyPlaceEntry.Companion._ID} INTEGER PRIMARY KEY, | |
| ${MyPlacesContract.MyPlaceEntry.Companion.COLUMN_NAME_NOTE} TEXT, | |
| ${MyPlacesContract.MyPlaceEntry.Companion.COLUMN_NAME_LONGITUDE} TEXT, | |
| ${MyPlacesContract.MyPlaceEntry.Companion.COLUMN_NAME_LATITUDE} TEXT, | |
| ${MyPlacesContract.MyPlaceEntry.Companion.COLUMN_NAME_ORDER} INTEGER)""" | |
| private val SQL_DELETE_ENTRIES = "DROP TABLE IF EXISTS ${MyPlacesContract.MyPlaceEntry.Companion.TABLE_NAME}" | |
| override fun onCreate(db: SQLiteDatabase) { | |
| db.execSQL(SQL_CREATE_ENTRIES) | |
| } | |
| override fun onOpen(db: SQLiteDatabase) { | |
| super.onOpen(db) | |
| db.execSQL("PRAGMA foreign_keys=ON") | |
| } | |
| override fun onUpgrade(db: SQLiteDatabase, oldVersion: Int, newVersion: Int) { | |
| // This database is only a cache for online data, so its upgrade policy is | |
| // to simply to discard the data and start over | |
| db.execSQL(SQL_DELETE_ENTRIES) | |
| onCreate(db) | |
| } | |
| override fun onDowngrade(db: SQLiteDatabase, oldVersion: Int, newVersion: Int) { | |
| onUpgrade(db, oldVersion, newVersion) | |
| } | |
| companion object { | |
| // If you change the database schema, you must increment the database version. | |
| val DATABASE_VERSION = 5 | |
| val DATABASE_NAME = "myPlaces.db" | |
| } | |
| } |
Baza jest dość prosta. Jedna tabelka, 5 kolumn (id, długość, szerokość, notka, kolejność). Zbyt wielkiej filozofii tu nie ma 😉
Pod guzikiem „znajdź mnie”, wywołuję funkcję, która pobiera położenie telefonu na podstawie GPS-a:
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| fun findMeButtonClick(view: View) { | |
| val locationManager = applicationContext.getSystemService(Context.LOCATION_SERVICE) as LocationManager | |
| val bestProvider = locationManager.getBestProvider(Criteria(), false) | |
| val location = locationManager.getLastKnownLocation(bestProvider) | |
| if (location != null) { | |
| longitude.text = location.longitude.toString() | |
| latitude.text = location.latitude.toString() | |
| } | |
| } |
Całą robotę robi: getLastKnownLocation, bo przecież nie muszę sama oprogramowywać całego modułu obliczającego moją lokalizację 😀
Przycisk z mapką obsługuję na poziomie adaptera podłączonego do ListView na głównym ekranie:
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| (holder.mapButton as ImageButton).setOnClickListener({ (context as MainActivity).showOnMap(myPlace.longitude.toDouble(), myPlace.latitude.toDouble(), myPlace.note) }) |
Żeby wyświetlić wybrany punkt na mapce, trzeba załadować odpowiednie parametry w nowo tworzone activity:
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| fun showOnMap(mLong: Double, mLat: Double, mTitle: String) { | |
| val activityIntent = Intent(this, MapsActivity::class.java) | |
| activityIntent.putExtra("long", mLong) | |
| activityIntent.putExtra("lat", mLat) | |
| activityIntent.putExtra("title", mTitle) | |
| this.startActivity(activityIntent) | |
| } |
Activity do obsługi mapki:
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| package com.projects.jezinka.myplaces | |
| import android.os.Bundle | |
| import android.support.v4.app.FragmentActivity | |
| import com.google.android.gms.maps.CameraUpdateFactory | |
| import com.google.android.gms.maps.GoogleMap | |
| import com.google.android.gms.maps.OnMapReadyCallback | |
| import com.google.android.gms.maps.SupportMapFragment | |
| import com.google.android.gms.maps.model.LatLng | |
| import com.google.android.gms.maps.model.MarkerOptions | |
| class MapsActivity : FragmentActivity(), OnMapReadyCallback { | |
| private var mMap: GoogleMap? = null | |
| private var mlong: Double = -34.0 | |
| private var mlat: Double = 151.0 | |
| private var mTitle: String = getString(R.string.here) | |
| override fun onCreate(savedInstanceState: Bundle?) { | |
| super.onCreate(savedInstanceState) | |
| setContentView(R.layout.activity_maps) | |
| mlong = intent.getDoubleExtra("long", mlong) | |
| mlat = intent.getDoubleExtra("lat", mlat) | |
| mTitle = intent.getStringExtra("title") | |
| val mapFragment = supportFragmentManager.findFragmentById(R.id.map) as SupportMapFragment | |
| mapFragment.getMapAsync(this) | |
| } | |
| override fun onMapReady(googleMap: GoogleMap) { | |
| mMap = googleMap | |
| val myPlace = LatLng(mlat, mlong) | |
| mMap!!.addMarker(MarkerOptions().position(myPlace).title(mTitle)) | |
| mMap!!.moveCamera(CameraUpdateFactory.newLatLng(myPlace)) | |
| mMap!!.animateCamera(CameraUpdateFactory.zoomTo(15f)) | |
| } | |
| } |
Reszta kodu na GitHubie – oczywiście bez kluczy do API 😉