另一个 Activity / 函数中的 Kotlin getString

Question

当我使用这段代码时，我的回收器视图应用程序崩溃了，因为我得到了一个空对象引用异常 bt，当时我不知道如何修复它。我试图对我的视图文本中的字符串进行软编码，但它不起作用。当我对其进行硬编码时，它可以工作:( 问题在

行

mContext.getString(R.string.strClick)

这是我的代码：

   package de.reuter.myapplication

import android.content.Context
import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import androidx.recyclerview.widget.LinearLayoutManager
import de.reuter.timetable.RecycleAdapter
import kotlinx.android.synthetic.main.activity_content_backend.*

class BackendContentActivity : AppCompatActivity() 
{
    val mContext: Context = this
    private val exampleList = generateDummyList(5, this)
    private val adapter = RecycleAdapter(exampleList, mContext)

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_content_backend)

        recycler_view.adapter = adapter
        recycler_view.layoutManager = LinearLayoutManager(this)
        recycler_view.setHasFixedSize(true)
    }

    private fun generateDummyList(size: Int, mContext: Context): ArrayList<AdapterItems> {
        val list = ArrayList<AdapterItems>()
        var drawable: Int
        var txt0: String
        var txt1: String
        var txt2: String = mContext.getString(R.string.strClick)

        for (i in 0 until size) {
            when (i % 5) {
                0 -> {
                    drawable = R.drawable.bg_circle_blue
                    txt0 = "M"
                    txt1 = "Monday"
                }
                1 -> {
                    drawable = R.drawable.bg_circle_green
                    txt0 = "T"
                    txt1 = "Tuesday"
                }
                2 -> {
                    drawable = R.drawable.bg_circle_red
                    txt0 = "W"
                    txt1 = "Wednesay"
                }
                3 -> {
                    drawable = R.drawable.bg_circle_yellow
                    txt0 = "T"
                    txt1 = "Thursday"
                }
                4 -> {
                    drawable = R.drawable.bg_circle_purple
                    txt0 = "F"
                    txt1 = "Friday"
                }
                else -> {
                    drawable = R.drawable.bg_circle_purple
                    txt0 = "W"
                    txt1 = "Wrong"
                }
            }
            var item = AdapterItems(drawable, txt0, txt1, txt2)
            list += item

        }
        return list
    }

}

我的回收适配器：

package de.reuter.timetable

import android.content.Context
import android.content.Intent
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.ImageView
import android.widget.TextView
import androidx.recyclerview.widget.RecyclerView
import com.google.android.material.snackbar.Snackbar
import de.reuter.myapplication.AdapterItems
import de.reuter.myapplication.MondayActivity
import de.reuter.myapplication.R
import kotlinx.android.synthetic.main.card_layout.view.*

class RecycleAdapter(private val exampleList: List<AdapterItems>, context: Context) :
    RecyclerView.Adapter<RecycleAdapter.ExampleViewHolder>() {
    var mContext = context

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ExampleViewHolder {
        val itemView = LayoutInflater.from(parent.context).inflate(
            R.layout.card_layout,
            parent, false
        )
        return ExampleViewHolder(itemView)
    }

    override fun onBindViewHolder(holder: ExampleViewHolder, position: Int) {
        val currentItem = exampleList[position]
        holder.imageView.setImageResource(currentItem.imageResource)
        holder.textView0.text = currentItem.text1
        holder.textView1.text = currentItem.text2
        holder.textView2.text = currentItem.text3
    }

    override fun getItemCount() = exampleList.size

    inner class ExampleViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {

        var imageView: ImageView = itemView.image_view
        var textView0: TextView = itemView.txtShortLetterM
        var textView1: TextView = itemView.txtViewMonday
        var textView2: TextView = itemView.txtClickLink

        init {
            imageView = itemView.findViewById(R.id.image_view)
            textView0 = itemView.findViewById(R.id.txtShortLetterM)
            textView1 = itemView.findViewById(R.id.txtViewMonday)
            textView2 = itemView.findViewById(R.id.txtClickLink)

            itemView.setOnClickListener { v: View ->
                var position: Int = getAdapterPosition()
                var text: String
                when (position) {
                    0 -> {
                        var intent = Intent(mContext, MondayActivity::class.java)
                        mContext.startActivity(intent)
                    }
                    else -> {
                        text = "Click detected on item $position"
                        Snackbar.make(
                            v, text,
                            Snackbar.LENGTH_LONG
                        ).setAction("Action", null).show()
                    }

                }


            }
        }
    }
    
}

非常感谢您的帮助

Answer 1

尝试将 generateDummyList(5, this) 调用移动到 BackendContentActivity 的 onCreate 方法 class:

class BackendContentActivity : AppCompatActivity() {
    private lateinit var exampleList: ArrayList<AdapterItems>

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_content_backend)

        exampleList = generateDummyList(5, this)

        // ...
    }
    // ...
}

另一个 Activity / 函数中的 Kotlin getString

Kotlin getString in another Activity / Function

android

adapter

getstring

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android-recyclerview