我正在为片段构建ViewHolder和适配器，当我尝试为ViewHolder创建OnClick时，我传递的上下文都没有工作。我可以使用activity getActivity() p0!!.context，itemView.context也package com._________.criminalintent
import android.os.Bundle
import android.support.v4.app.Fragment
import android.support.v7.widget.LinearLayoutManager
import android.support.v7.widget.RecyclerView
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.TextView
import android.widget.Toast
class CrimeListFragment: Fragment() {
private var mCrimeRecyclerView: RecyclerView? = null
private var mAdapter: CrimeAdapter? = null
override fun onCreateView(inflater: LayoutInflater?, container: ViewGroup?, savedInstanceState: Bundle?): View? {
// fragment_crime_list.xml has a RecyclerView element = crime_recycler_view
// inflate the fragment into the activity
val view = inflater!!.inflate(R.layout.fragment_crime_list, container, false)
// grab the recyclerView and give it a required layoutManager
mCrimeRecyclerView = view.findViewById(R.id.crime_recycler_view)
mCrimeRecyclerView!!.layoutManager = LinearLayoutManager(activity)
updateUI()
return view
}
private fun updateUI() {
val crimeLab = CrimeLab.get(activity)
val crimes = crimeLab.getCrimes()
mAdapter = CrimeAdapter(crimes)
// Connect the adapter to the recyclerView
mCrimeRecyclerView!!.adapter = mAdapter
}
/**
* in Kotlin, we must give the view passed into the constructor directly
* as a substitute for a super() call
*
* create a ViewHolder that holders the crime list item's view
*
* super(itemView) = super(inflater!!.inflate(R.layout.list_item_crime, parent, false))
* MUST give it the direct value in Kotlin
*/
private class CrimeHolder(inflater: LayoutInflater?, parent: ViewGroup):
RecyclerView.ViewHolder(inflater!!.inflate(R.layout.list_item_crime, parent, false)),
View.OnClickListener {
private var mCrime: Crime? = null
/**
* When given a crime, this CrimeHolder will update the title and date for this Crime
*/
fun bind(crime: Crime) {
mCrime = crime
val titleTextView = itemView.findViewById<TextView>(R.id.crime_title)
val dateTextView = itemView.findViewById<TextView>(R.id.crime_date)
titleTextView.text = mCrime!!.mTitle
dateTextView.text = mCrime!!.mDate.toString()
}
override fun onClick(p0: View?) {
Toast.makeText(WHAT_TO_PUT_HERE, "${mCrime!!.mTitle} clicked!", Toast.LENGTH_SHORT / 2)
.show()
}
}
private class CrimeAdapter(private var mCrimes: MutableList<Crime>):
RecyclerView.Adapter<CrimeHolder>() {
/**
* - Calls our CrimeHolder to make our custom ViewHolders
* - Called by RecyclerView when it needs a new view to display
* - Gets the layoutInflater from the ViewGroup and returns a CrimeHolder of it
*/
override fun onCreateViewHolder(parent: ViewGroup?, viewType: Int): CrimeHolder
= CrimeHolder(LayoutInflater.from(parent!!.context), parent)
/**
* Bind the crime (data) to the CrimeHolder
*/
override fun onBindViewHolder(holder: CrimeHolder?, position: Int) {
holder!!.bind(mCrimes[position])
}
/**
* Sees how many items are in the RecyclerView that need to be shown
*/
override fun getItemCount(): Int = mCrimes.size
}
}
也可以使用queryParameters = { [param]: true };
。我应该从哪里获取我的上下文，以及如何引用它？
.bigBox
{
width: 700px;
height: 500px;
background: grey;
}
.box{
width: 32%;
display: inline-block;
background: yellow;
}答案 0 :(得分：4)
在您的实施中，您可以安全地使用提供给Context的{{1}} View
OnClickListener请记住设置onclick：
override fun onClick(p0: View) {
Toast.makeText(p0.context, "${mCrime!!.mTitle} clicked!", Toast.LENGTH_SHORT / 2)
.show()
}
此外，默认情况下，所有Kotlin类都嵌套（fun bind(crime: Crime) {
mCrime = crime
val titleTextView = itemView.findViewById<TextView>(R.id.crime_title)
val dateTextView = itemView.findViewById<TextView>(R.id.crime_date)
titleTextView.text = mCrime!!.mTitle
dateTextView.text = mCrime!!.mDate.toString()
itemView.setOnClickListener(this)
}
）。所以你的static相当于Java中的private class CrimeHolder。这就是您无法在private static class CrimeHolder
getActivity()的原因
答案 1 :(得分：1)
在持有人中使用itemView.context属性。
编辑：
您onClick没有工作的原因＆＃34; （未被调用）是因为您尚未注册onClickListener，例如：
itemView.setOnClickListener(this)
在您的持有人init或bind内。
答案 2 :(得分：0)
itemView.setOnClickListener {
Toast.makeText(itemView.context, "Item is clicked $position", Toast.LENGTH_SHORT).show() }
}