CODEWITHSUNDEEP
androidandroid-activitykotlin
Angelina
Angelina

Reputation: 1563

Reuse methods in Kotlin, Android

I need to open one activity from several different points in the app. Let's say from Settings fragment, Main Activity and Navigation drawer (fragment). I don't want to copy/paste the same method and the method is very specific, it should be exactly the same (because it registeres Firebase events). How to structure the code in effective way? Where to put this method? One idea is to have a global ActivityUtils.kt file with just methods and it would be used to store these methods. I'm interested in the alternatives and what are pros and cons of each.

Upvotes: 0

Views: 1703

Answers (3)

Dmitry
Dmitry

Reputation: 344

Why not to use MVP? Like, 

interface IView { 
    val context: Context 
}

interface IPresenter { 
    fun launchActivity(view: IView) 
}

class MyActivityModel
{
    var key = "key"
    /*some other data*/

    fun getParcelableObject(): Parcelable
    {
        return /*some parcelable from model data*/
    }
}

class MyActivity : AppCompatActivity(), IView
{
    override val context: Context
        get() = this
}

class MyActivityPresenter() : IPresenter
{
    private var model: MyActivityModel = MyActivityModel()

    override fun launchActivity(view: IView)
    {
        val intent = Intent(view.context, MyActivity::class.java)
        intent.putExtra(model.key, model.getParcelableObject())
        view.context.startActivity(intent)
    }

    fun setSomeDataToModel(someData: Any) {

    }
}

/*Everyone who wants to use presenter, must be a Context and implement IView*/
fun use()//in some fragment, or activity implementing IView
{
    MyActivityPresenter().launchActivity(this)
    //or
    val presenter = MyActivityPresenter()
    presenter.setSomeDataToModel("some data")
    presenter.launchActivity(this)
}

Upvotes: 0

Sergio
Sergio

Reputation: 30625

I would create a companion object in the Activity you need to open:

class YourActivity : AppCompatActivity() {

    companion object {
        fun start(ctx: Context) {
            // put your logic here (registering of Firebase events)

            val i = Intent(ctx, YourActivity::class.java)
            ctx.startActivity(i)
         }
    }
}

And call it from another activity:

YourActivity.start(this)

or from another fragment:

YourActivity.start(context)

Upvotes: 4

TheWanderer
TheWanderer

Reputation: 17824

Use an extension method:

fun Activity.doMyStuff() {}

That can be called from any class extending Activity:

doMyStuff()

Extension functions like this shouldn't go inside a class, but rather inside a file. So if you were to make an ActivityUtils.kt file, don't have any sort of class ActivityUtils {} stuff in it. The function(s) should just go directly into the file.

Upvotes: 0

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