kotlin Dagger2 适配器中的依赖注入

Question

Expected Result

What am I'm trying to do is to inject my AccountType class to ExpandableAdpter and on click of child view what to check user Type?

How to implement dagger in Adapter?

Dagger working fine with Fragment and Activity. only getting null in adapter because unable to initialize adapter to dagger

Sample for interface in dagger

//Di interface 
interface ActivityComponent : BaseComponent {
// adapter
fun inject(expDragSwipeAdapter: ExpandableDraggableSwipeableAdapter)

}

Adapter onCreate of group and childview

@Inject lateinit var accountType: Accounts
private lateinit var activityComponent: ActivityComponent

override fun onCreateGroupViewHolder(parent: ViewGroup, viewType: Int): MyGroupViewHolder {
    activityComponent.inject(this)
    val inflater = LayoutInflater.from(parent.context)
    val v: View
    if (isDragRequire) {
        v = inflater.inflate(R.layout.row_edit_watchlist, parent, false)
    } else {
        v = inflater.inflate(R.layout.row_watchlist, parent, false)
    }
    return MyGroupViewHolder(v, isDragRequire, mContext)
}

override fun onCreateChildViewHolder(parent: ViewGroup, viewType: Int): MyChildViewHolder {
    activityComponent.inject(this)
    val inflater = LayoutInflater.from(parent.context)
    val v = inflater.inflate(R.layout.row_child_watchlist, parent, false)
    return MyChildViewHolder(v, false)
}

I'm facing the error in this line activityComponent.inject(this)

On The onclick checking AccountType and implement business logic

Answer 1

There is no need to request injection from a Dagger 2 Component inside an Adapter for a RecyclerView or a ListView.

For Fragments and Activities we have no choice other than to explictly request injection from a Component since these objects are instantiated by the Android OS and we don't "control" the constructors.

For everything else, including Adapters, you should prefer constructor injection and then setting parameters manually.

Something idiomatic would look something like the following. Inside your Fragment:

class MyFragment : Fragment {

    @Inject
    lateinit var accountsAdapter: accountsAdapter

    @Inject
    lateinit var accountsRepository: AccountsRepository

    //load accounts in onStart or wherever you decide to load
    //when loading finished, execute the following method in a callback

    fun onAccountsLoaded(accounts: Accounts) {
        adapter.setAccounts(accounts)
    }
}

For example, your Adapter could do something like:

class Adapter @Inject constructor() : BaseAdapter {

    fun setAccounts(accounts: Accounts) {
        this.accounts = accounts
        notifyDataSetChanged()
    } 
}

You can see the official Google Android Architectural examples for using a ListView with Dagger 2. The link is here