【发布时间】：2021-07-22 15:13:52
【问题描述】：
结果总是返回null，我不知道是什么错误，我看到其他人的问题我没有得到我需要的东西。
class DatabaseLists(private val context: Context?) {
private lateinit var database: SQLiteDatabase
val getPrayerContentList: ArrayList<PrayerModel>
@SuppressLint("Recycle")
get() {
database = DatabaseOpenHelper(context).readableDatabase
val cursor: Cursor = database.query(
"table_prayer",
null,
null,
null,
null,
null,
null,
null
)
val contentList = ArrayList<PrayerModel>()
if (cursor.moveToFirst()) {
while (!cursor.isAfterLast) {
val contents = PrayerModel(
cursor.getString(cursor.getColumnIndex("prayer_name")),
cursor.getString(cursor.getColumnIndex("ayah_name")),
cursor.getString(cursor.getColumnIndex("arabic")),
cursor.getString(cursor.getColumnIndex("latin")),
cursor.getString(cursor.getColumnIndex("translate")),
cursor.getString(cursor.getColumnIndex("description"))
)
contentList.add(contents)
cursor.moveToNext()
if (cursor.isClosed) {
cursor.close()
}
}
}
return contentList
}
class PrayerActivity : AppCompatActivity(), MainContract.MainView {
private lateinit var binding: ActivityPrayerBinding
private var database: SQLiteDatabase? = null
private lateinit var preferences: SharedPreferences
private lateinit var editor: SharedPreferences.Editor
lateinit var carlist: ArrayList<PrayerModel>
private lateinit var prayerContentList: MutableList<PrayerModel>
private lateinit var prayerAdapter: PrayerAdapter
private lateinit var mainPresenterImpl: MainPresenterImpl
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = DataBindingUtil.setContentView(this, R.layout.activity_prayer)
setSupportActionBar(binding.toolbar)
preferences = PreferenceManager.getDefaultSharedPreferences(this)
editor = preferences.edit()
PreferenceManager.getDefaultSharedPreferences(this)
database = DatabaseOpenHelper(this).readableDatabase
prayerContentList = DatabaseLists(this).getPrayerContentList
mainPresenterImpl = MainPresenterImpl(this, this)
initMainContent()
}
override fun initMainContent() {
val verticalLayout = LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false)
binding.rvMainContent.layoutManager = verticalLayout
prayerAdapter = PrayerAdapter(this, prayerContentList)
binding.rvMainContent.adapter = prayerAdapter
}
}
data class PrayerModel (
val strPrayerName: String?,
val strAyahName: String?,
val strContentArabic: String?,
val strContentLatin: String?,
val strContentTranslation: String?,
val strContentDescription: String?)
我的适配器
class PrayerAdapter(context: Context, private val prayerContentList: MutableList<PrayerModel>) :
RecyclerView.Adapter<PrayerViewHolder>() {
private val context: Context? = null
private val inflater = LayoutInflater.from(context)
private var currentIndex: Int = -1
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): PrayerViewHolder {
return PrayerViewHolder(inflater.inflate(R.layout.item_prayer_content, parent, false))
}
override fun getItemCount(): Int {
return prayerContentList.size
}
override fun onBindViewHolder(holder: PrayerViewHolder, position: Int) {
val strContentArabic = prayerContentList[position].strContentArabic
val strContentLatin = prayerContentList[position].strContentLatin
val strContentTranslation = prayerContentList[position].strContentTranslation
val strContentDescription = prayerContentList[position].strContentDescription
val strPrayerName = prayerContentList[position].strPrayerName
val strAyahName = prayerContentList[position].strAyahName
holder.tvContentPrayerName.text = strPrayerName
holder.tvContentAyahName.text = strAyahName
holder.itemView.setOnClickListener { v ->
val context: Context = v.context
val intent = Intent(context, PrayerReadActivity::class.java)
intent.putExtra("ARABIC_TEXT", strContentArabic?.get(position))
intent.putExtra("LATIN_TEXT", strContentLatin!![position])
intent.putExtra("TRANSLATION_TEXT", strContentTranslation!![position])
intent.putExtra("DESCRIPTION_TEXT", strContentDescription!![position])
context.startActivity(intent)
Log.d(TAG, "-->name = $strContentArabic")
}
}
}
我的 2Activity 可以有这样的代码，并试图在另一个活动中获取额外的字符串但返回 null？
class PrayerReadActivity() : AppCompatActivity() {
private var database: SQLiteDatabase? = null
private lateinit var prayerContentList: MutableList<PrayerModel>
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_prayer_read)
LockOrientation(this).lock()
PreferenceManager.getDefaultSharedPreferences(this)
database = DatabaseOpenHelper(this).readableDatabase
prayerContentList = DatabaseLists(this).getPrayerContentList
val extras = intent.extras
if (null != extras) {
val arabic = extras.getString("ARABIC_TEXT").toString()
val latin = extras.getString("LATIN_TEXT").toString()
val translation = extras.getString("TRANSLATION_TEXT").toString()
val description = extras.getString("DESCRIPTION_TEXT").toString()
Log.d(ContentValues.TAG, "-->arabic = $arabic")
tvContentArabic2.text = arabic
tvContentLatin2.text = latin
tvContentTranslation2.text = translation
tvContentDescription2.text = description
Log.d(ContentValues.TAG, "-->arabic = $arabic")
Log.d(ContentValues.TAG, "-->latin = $latin")
Log.d(ContentValues.TAG, "-->translation = $translation")
Log.d(ContentValues.TAG, "-->description = $description")
}
我尝试替换
val arabic = intent.getStringExtra("ARABIC_TEXT").toString()
它仍然返回 null 吗？
2021-07-22 22:31:16.411 9607-9607/com.example.yasiin D/ContentValues: -->arabic = null
2021-07-22 22:31:16.411 9607-9607/com.example.yasiin D/ContentValues: -->arabic = null
2021-07-22 22:31:16.411 9607-9607/com.example.yasiin D/ContentValues: -->latin = null
2021-07-22 22:31:16.411 9607-9607/com.example.yasiin D/ContentValues: -->translation = null
2021-07-22 22:31:16.411 9607-9607/com.example.yasiin D/ContentValues: -->description = null
【问题讨论】：
-
值是否显示在回收站视图中？
-
2021-07-22 23:34:04.191 9270-9270/com.example.yasiin D/ContentValues: -->strPrayerName = 祷告的名字 2021-07-22 23:34:04.191 9270- 9270/com.example.yasiin D/ContentValues: -->strAyahName = 4
-
数值是否显示在屏幕上？
标签： android kotlin android-intent