name: portada
class: portada-slide, center, middle

# Realm - Android

.footnote[Mateu Yábar Valles]

---

---
# Real-Android
Al ser una base de dades offline first, està pensada per dispositius mòbils.

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# Flow to LiveData

```
fun listFlow() = realm.query<ItemRealm>().find().asFlow()
```

```
// ViewModel
val itemListLiveData = locationRepository.listFlow().map { it.list.toList() }.asLiveData()
```

---
# Guardar login
- Un cop fet el login l'usuari queda guardat a no haver de fer el login la seguent vegada que s'obri l'aplicació.
- Pots mirar si està loggejat amb:

```
fun loggedIn() = realmApp.currentUser?.loggedIn ?: false
```

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# Splash screen
Pots usar una splash screen per a que a l'app et dirigeixi al login/register o al mapa

<div class="mermaid fullwidth" style="width:100%;">
graph LR
    Spash[Spash] --> Login[Login]
    Spash[Spash] --> Map[Map]
</div>

---
# Arch

```
/**
 * Contains all the operations with locations
 */
class LocationRepository(realm: Realm){
    fun listFlow() : Flow<List<LocationRealm>> = TODO()
    
    // More location functions
}
```

---
# Arch

```
/**
 * Manages the realm app
 */
class RealmManager{
    val realmApp = App.create(AppConfiguration.Builder("MY_APPLICATION_ID").log(LogLevel.ALL).build())
    var realm : Realm? = null

fun loggedIn() = realmApp.currentUser?.loggedIn ?: false

suspend fun register(username: String, password: String): Boolean = TODO()

suspend fun login(username: String, password: String) : Boolean = TODO()
}
```

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#Arch

```
/**
 * Singleton with services
 */
object ServiceLocator {
    val realmManager = RealmManager()
    lateinit var locationRepository: LocationRepository

/**
     * Call when user logged in and realm created
     */
    fun configureRealm(){
        requireNotNull(realmManager.realm)
        val realm = realmManager.realm!!
        locationRepository = LocationRepository(realm)
    }
}
```

---
# Realm imatge

```
open class RealmModelWithPicture(
        var picture: ByteArray? = null,
        var owner_id: String = "",
        @PrimaryKey
        var _id: ObjectId = ObjectId.create(),
) : RealmObject {
        // Declaring empty contructor for Realm
        constructor() : this(owner_id = "") {}
}
```

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# Android display Image
```
val bmp = BitmapFactory.decodeByteArray(location.picture, 0, location.picture!!.size)
val image = binding.image
image.setImageBitmap(bmp)
```

---
# Thumbnail
```
val thumbImage = ThumbnailUtils.extractThumbnail(
    BitmapFactory.decodeFile(args.uri),
    200,
    200
)
val stream = ByteArrayOutputStream()
thumbImage.compress(Bitmap.CompressFormat.PNG, 100, stream)
val thumbByteArray: ByteArray = stream.toByteArray()
thumbImage.recycle()
```

---
# Exemple
https://gitlab.com/mateuyabar_at_itb/realmAndroidSample?authuser=0