将RecyclerView数据绑定到新活动（Android-Kotlin）

Question

Hello Guys i want pass on the data used to populate the recyclerview.

class RecyclerViewAdapter(val list: List<ListModel>): RecyclerView.Adapter<RecyclerViewAdapter.ListViewHolder>(){

    override fun onCreateViewHolder(p0: ViewGroup, p1: Int): ListViewHolder {
        val layoutInflater = LayoutInflater.from(p0.context)
        val itemlist = layoutInflater.inflate(R.layout.recycler_item,p0,false)
        return ListViewHolder(itemlist)
    }

    override fun onBindViewHolder(p0: ListViewHolder, p1: Int) {
        val myList: ListModel = list[p1]

        p0.itemView.txtImageName?.text = myList.title
        Glide.with(p0.itemView.context)
            .load(myList.postimg)
            .into(p0.itemView.listImage);

    }

    override fun getItemCount(): Int {
        return list.size
    }

    inner class ListViewHolder(v: View) : RecyclerView.ViewHolder(v){
        init {
            v.setOnClickListener {
                val intent = Intent(v.context, WebviewActivity::class.java)
                intent.putExtra("key", "testfromact") //this is where i want to put myList.title variable
                v.context.startActivity(intent)
            }

        }
    }

}

As you can see im trying pass the data to the new activity... What is the best ad easy way to do this

Answer 1

Optimized code for passing data from RecyclerView to Activity:

This is the Adapter code:

1. I haven't used Kotlin synthetic to and used the view in onBindViewHolder() because of the problem, each time it will fetch the view and show it and it's not best practice, we use ViewHolder only to defeat this purpose and achieve caching. So look How I'm doing that in the inner class.

2. For optimized code, I used this beautiful library. Anko is a Kotlin library which makes Android application development faster and easier. It makes your code clean and easy to read, and lets you forget about rough edges of the Android SDK for Java.

    class TreeAdapter(private val listSurveyData: List<Tree>, val context: Context) : RecyclerView.Adapter<TreeAdapter.TreeViewHolder>() { override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): TreeViewHolder { val view = LayoutInflater.from(parent.context).inflate(R.layout.item_layout_tree, parent, false) return TreeViewHolder(view) } override fun getItemCount(): Int = listSurveyData.size override fun onBindViewHolder(holder: TreeViewHolder, position: Int) { holder.setUpViewHolder(listSurveyData[position]) } inner class TreeViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) { private val txtSpeciesName: TextView = itemView.txt_speciesName private val ctlContainer: ConstraintLayout = itemView.ctl_container fun setUpViewHolder(tree: Tree) { txtSpeciesName.text = tree.species ctlContainer.setOnClickListener { context.startActivity<MainActivity>(SURVERY_DATA_KEY to tree) } } } 

   }

Also How to use it!

In Activity: Also, Extend the Tree data class with Serializable!

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        val tree = intent.getSerializableExtra(SURVERY_DATA_KEY) as Tree
    } 
}