Android Kotlin-simple Array Adapter with ListView

Question

I am new to Kotlin and/or coding. The below mentioned are the code I made to populate a List View. But as I run the code, the activity_main.xml file is inflated but the text data are not attached.

Datasource.kt

class Datasource{

     companion object{
       val affirmationList: List<String> = listOf(
           "Affirmation_1", "Affirmation_2", "Affirmation_3", "Affirmation_4")} 
     

}

Here is the CustomAdapter.kt,

class CustomAdapter(val mContext:Context, val layoutId:Int, val textId: Int, val x: List<String>) :ArrayAdapter<Datasource>(mContext, layoutId, textId) {}

Here is MainActivity.kt

class MainActivity : AppCompatActivity()
 {
override fun onCreate(savedInstanceState: Bundle?) {

    super.onCreate(savedInstanceState)

    setContentView(R.layout.activity_main)

// Item.View is the Id of ListView in activity_main.xml

    val itemListView= findViewById<ListView>(R.id.Item_View)

   // item_list is the Id of item_list.xml & Affirmation_Text is the Id of TextView in item_list.xml

    val customAdapterUse = CustomAdapter(this,R.layout.item_list, R.id.Affirmation_Text, Datasource.affirmationList)

    itemListView.adapter = customAdapterUse


}
}

E_net4 · Accepted Answer · 2022-07-31 16:26:27Z

0

You need to learn how the recycler view works. You haven't implemented any of the RecylerView adapter functions. I would recommend you watch some YouTube videos or tutorials on how to populate a list using RecyclerView. After you understand how the recycler view works, you can get some help from the documentation here.

Here is a code sample to give you an idea as to how your recycler view adapter should look like:


class CustomAdapter(private val dataSet: Array<String>) :
        RecyclerView.Adapter<CustomAdapter.ViewHolder>() {

    /**
     * Provide a reference to the type of views that you are using
     * (custom ViewHolder).
     */
    class ViewHolder(view: View) : RecyclerView.ViewHolder(view) {
        val textView: TextView

        init {
            // Define click listener for the ViewHolder's View.
            textView = view.findViewById(R.id.textView)
        }
    }

    // Create new views (invoked by the layout manager)
    override fun onCreateViewHolder(viewGroup: ViewGroup, viewType: Int): ViewHolder {
        // Create a new view, which defines the UI of the list item
        val view = LayoutInflater.from(viewGroup.context)
                .inflate(R.layout.text_row_item, viewGroup, false)

        return ViewHolder(view)
    }

    // Replace the contents of a view (invoked by the layout manager)
    override fun onBindViewHolder(viewHolder: ViewHolder, position: Int) {

        // Get element from your dataset at this position and replace the
        // contents of the view with that element
        viewHolder.textView.text = dataSet[position]
    }

    // Return the size of your dataset (invoked by the layout manager)
    override fun getItemCount() = dataSet.size

}

edited Jul 31, 2022 at 16:26

E_net4

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answered Jul 31, 2022 at 1:48

Arsh

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4 Comments

Jaguar Over a year ago

I am not asking about RecyclerView.Adapter, as I am not using that. I have only one TextView and trying to use simple ArrayAdapter to display a list of items. Would appreciate, if you or any of you can clarify why items are not getting attached to the list. I don't notice any error on the code. In Logcat, I see this, 'W/System: A resource failed to call close.'

Arsh Over a year ago

Sorry, I will try to edit my code according to your needs. can you add your whole logcat error? the log that you provide does not provide any information.

writer_chris Over a year ago

@Jaguar Your adapter class is empty, you have to write these functions mentioned above. How should any viewholder know any information if you don' provide these infos.

writer_chris Over a year ago

as you would like to yous dynamic lists you can use also ListAdapter developer.android.com/guide/topics/ui/layout/recyclerview

Jaguar · Accepted Answer · 2022-08-04 01:07:07Z

0

Thanks for all of your feedback. I worked it out. Just changed CustomAdaptder class (added String type for ArrayAdapter and added data source variable x to the ArrayAdapter constructor. The final code is as below:

CustomAdapter(val mContext:Context, val layoutId:Int, val textId: Int, val x: List<String>) :ArrayAdapter<String>(mContext, layoutId, textId, x) {}

The code, which was not attaching data:

class CustomAdapter(val mContext:Context, val layoutId:Int, val textId: Int, val x: List<String>) :ArrayAdapter<Datasource>(mContext, layoutId, textId) {}

answered Aug 4, 2022 at 1:07

Jaguar

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