Kotlin SQlite：选择记录时应用程序崩溃
Kotlin SQlite: Application crashes when selecting a record
我正在尝试使用 kotlin 语言在 Android studio 中将 int 值实现到我的简单 sqlite 程序中。
我是 Kotlin 的初学者，所以我首先只使用字符串制作了一个 sqlite 程序，但现在我想使用 Int 值。
我设法使值成为 int 并插入工作正常，但是在选择记录时，应用程序崩溃。
这是日志猫。
15115-15115/com.example.sqlitedemo E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.sqlitedemo, PID: 15115
android.content.res.Resources$NotFoundException: String resource ID #0x3
at android.content.res.Resources.getText(Resources.java:444)
at android.widget.TextView.setText(TextView.java:6412)
at com.example.sqlitedemo.MainActivity$onCreate.invoke(MainActivity.kt:49)
错误 kt 49 和 44：与
有关
adapter?.setOnClickItem {
Toast.makeText(this,it.name,Toast.LENGTH_SHORT).show()
//レコード更新
edName.setText(it.name)
edEmail.setText(it.email)
edBuyAmount.setText(it.buyamount)
edUseAmount.setText(it.useamount)
std = it
}
at com.example.sqlitedemo.MainActivity$onCreate.invoke(MainActivity.kt:44)
at com.example.sqlitedemo.StudentAdapter.onBindViewHolder$lambda-0(StudentAdapter.kt:32)
错误 kt:32 与
有关
override fun onBindViewHolder(holder: StudentViewHolder, position: Int) {
val std = stdList[position]
holder.bindView(std)
holder.itemView.setOnClickListener{onClickItem?.invoke(std)}
holder.btnDelete.setOnClickListener{onClickDeleteItem?.invoke(std)}
}
at com.example.sqlitedemo.StudentAdapter.$r8$lambda$rFSStv71TK0PX1i3mffPAEhmz7s(Unknown Source:0)
at com.example.sqlitedemo.StudentAdapter$$ExternalSyntheticLambda1.onClick(Unknown Source:4)
at android.view.View.performClick(View.java:7448)
at android.view.View.performClickInternal(View.java:7425)
at android.view.View.access00(View.java:810)
at android.view.View$PerformClick.run(View.java:28305)
at android.os.Handler.handleCallback(Handler.java:938)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:223)
at android.app.ActivityThread.main(ActivityThread.java:7656)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
MainActivity class()
class MainActivity : AppCompatActivity() {
private lateinit var edName: EditText
private lateinit var edEmail: EditText
private lateinit var edBuyAmount:EditText
private lateinit var edUseAmount:EditText
private lateinit var btnAdd: Button
private lateinit var btnView: Button
private lateinit var btnUpdate: Button
private lateinit var sqLiteHelper: SQLiteHelper
private lateinit var recyclerView: RecyclerView
private var adapter: StudentAdapter?=null
private var std:StudentModel?=null
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
initView()
initRecyclerView()
sqLiteHelper= SQLiteHelper(this)
//Show recycler view
val stdList = sqLiteHelper.getAllStudent()
Log.e("ok","${stdList.size}")
adapter?.addItems(stdList)
btnAdd.setOnClickListener{ addStudent()}
btnView.setOnClickListener{getStudents()}
btnUpdate.setOnClickListener{updateStudent()}
adapter?.setOnClickItem {
Toast.makeText(this,it.name,Toast.LENGTH_SHORT).show()
//data update
edName.setText(it.name)
edEmail.setText(it.email)
edBuyAmount.setText(it.buyamount)
edUseAmount.setText(it.useamount)
std = it
}
adapter?.setOnClickDeleteItem{
deleteStudent(it.id)
}
}
private fun deleteStudent(id:Int){
val builder = AlertDialog.Builder(this)
builder.setMessage("do you want to delete?")
builder.setCancelable(true)
builder.setNegativeButton("no"){dialog, _ ->
dialog.dismiss()
}
builder.setPositiveButton("yes"){dialog, _ ->
sqLiteHelper.deleteStudentById(id)
getStudents()
dialog.dismiss()
}
val alert = builder.create()
alert.show()
}
private fun updateStudent(){
val name = edName.text.toString()
val email = edEmail.text.toString()
val buyAmount = edBuyAmount.text.toString().toInt()
val useAmount = edUseAmount.text.toString().toInt()
//Check record not changed
if(name == std?.name && email == std?.email && buyAmount == std?.buyamount && useAmount == std?.useamount){
Toast.makeText(this,"Data wasnt updated",Toast.LENGTH_SHORT).show()
return
}
if(std == null) return
val std = StudentModel(id=std!!.id,name = name,email = email, buyamount = buyAmount, useamount = useAmount )
val status = sqLiteHelper.updateStudent(std)
if(status > -1){
clearEditText()
getStudents()
}else{
Toast.makeText(this,"error",Toast.LENGTH_SHORT).show()
}
}
private fun getStudents(){
val stdList = sqLiteHelper.getAllStudent()
Log.e("ok","${stdList.size}")
adapter?.addItems(stdList)
}
private fun addStudent(){
val name = edName.text.toString()
val email = edEmail.text.toString()
val buyAmount = edBuyAmount.text.toString().toInt()
val useAmount = edUseAmount.text.toString().toInt()
if(name.isEmpty()||email.isEmpty()|| buyAmount.toString().isEmpty() ||useAmount.toString().isEmpty()){
Toast.makeText(this,"enter data",Toast.LENGTH_SHORT).show()
}else{
val std = StudentModel(name = name, email=email, buyamount=buyAmount, useamount=useAmount)
val status = sqLiteHelper.insertStudent(std)
//Check Insert success or not success
if(status > -2){
Toast.makeText(this,"added data",Toast.LENGTH_SHORT).show()
clearEditText()
}else{
Toast.makeText(this,"data is not found。",Toast.LENGTH_SHORT).show()
}
}
}
private fun clearEditText(){
edName.setText("")
edEmail.setText("")
edBuyAmount.setText("")
edUseAmount.setText("")
edName.requestFocus()
}
private fun initRecyclerView(){
recyclerView.layoutManager=LinearLayoutManager(this)
adapter = StudentAdapter()
recyclerView.adapter=adapter
}
private fun initView(){
edName = findViewById(R.id.edName)
edEmail = findViewById(R.id.edEmail)
edBuyAmount=findViewById(R.id.edBuyAmount)
edUseAmount=findViewById(R.id.edUseAmount)
btnAdd = findViewById(R.id.btnAdd)
btnView = findViewById(R.id.btnView)
btnUpdate=findViewById(R.id.btnUpdate)
recyclerView=findViewById(R.id.recyclerView)
}
}
记录适配器class
class StudentAdapter: RecyclerView.Adapter<StudentAdapter.StudentViewHolder>() {
private var stdList: ArrayList<StudentModel> = ArrayList()
private var onClickItem: ((StudentModel) -> Unit)?=null
private var onClickDeleteItem: ((StudentModel) -> Unit)?=null
fun addItems(items: ArrayList<StudentModel>){
this.stdList=items
notifyDataSetChanged()
}
fun setOnClickItem(callback:(StudentModel)->Unit){
this.onClickItem = callback
}
fun setOnClickDeleteItem(callback: (StudentModel) -> Unit){
this.onClickDeleteItem = callback
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int)= StudentViewHolder (
LayoutInflater.from(parent.context).inflate(R.layout.card_items_rec,parent,false)
)
override fun onBindViewHolder(holder: StudentViewHolder, position: Int) {
val std = stdList[position]
holder.bindView(std)
holder.itemView.setOnClickListener{onClickItem?.invoke(std)}
holder.btnDelete.setOnClickListener{onClickDeleteItem?.invoke(std)}
}
override fun getItemCount(): Int {
return stdList.size
}
class StudentViewHolder(var view: View):RecyclerView.ViewHolder(view){
private var id = view.findViewById<TextView>(R.id.tvId)
private var name = view.findViewById<TextView>(R.id.tvName)
private var email = view.findViewById<TextView>(R.id.tvEmail)
private var buyAmount = view.findViewById<TextView>(R.id.tvBuyAmount)
private var useAmount = view.findViewById<TextView>(R.id.tvUseAmount)
var btnDelete = view.findViewById<TextView>(R.id.deleteBtn)
fun bindView(std:StudentModel){
id.text = std.id.toString()
name.text = std.name
email.text = std.email
buyAmount.text = std.buyamount.toString()
useAmount.text = std.useamount.toString()
}
}
}
学生数据库class
class SQLiteHelper(context:Context):SQLiteOpenHelper(context,DATABASE_NAME,null,DATABASE_VERSION){
companion object{
private const val DATABASE_VERSION =1
private const val DATABASE_NAME ="student.db"
private const val TBL_STUDENT = "tblRecords"
private const val ID ="[id]"
private const val NAME ="[name]"
private const val EMAIL ="[email]"
private const val BUYAMOUNT ="[buyamount]"
private const val USEAMOUNT ="[useamount]"
}
override fun onCreate(db: SQLiteDatabase?) {
val createTblStudent = ("CREATE TABLE "+ TBL_STUDENT + "("
+ ID + " INTEGER PRIMARY KEY,"+ NAME +" TEXT,"+
EMAIL +" TEXT,"+ BUYAMOUNT +" INTEGER,"+ USEAMOUNT +" INTEGER"+")")
db?.execSQL(createTblStudent)
}
override fun onUpgrade(db: SQLiteDatabase?, oldVersion: Int, newVersion: Int) {
db!!.execSQL("DROP TABLE IF EXISTS $TBL_STUDENT")
onCreate(db)
}
fun insertStudent(std: StudentModel): Long {
val db = this.writableDatabase
val contentValues = ContentValues()
contentValues.put(ID, std.id)
contentValues.put(NAME, std.name)
contentValues.put(EMAIL, std.email)
contentValues.put(BUYAMOUNT,std.buyamount)
contentValues.put(USEAMOUNT,std.useamount)
val success = db.insert(TBL_STUDENT,null,contentValues)
db.close()
return success
}
fun getAllStudent():ArrayList<StudentModel>{
val stdList: ArrayList<StudentModel> = ArrayList()
val selectQuery = "SELECT * FROM $TBL_STUDENT"
val db = this.readableDatabase
val cursor: Cursor?
try {
cursor = db.rawQuery(selectQuery,null)
}catch (e:Exception){
e.printStackTrace()
db.execSQL(selectQuery)
return ArrayList()
}
var id: Int
var name: String
var email: String
var buyamount: Int
var useamount: Int
if(cursor.moveToFirst()){
do{
id = cursor.getInt(cursor.getColumnIndexOrThrow("id"))
name = cursor.getString(cursor.getColumnIndexOrThrow("name"))
email = cursor.getString(cursor.getColumnIndexOrThrow("email"))
buyamount = cursor.getString(cursor.getColumnIndexOrThrow("buyamount")).toInt()
useamount = cursor.getString(cursor.getColumnIndexOrThrow("useamount")).toInt()
val std = StudentModel(id = id,name = name,email=email,buyamount=buyamount,useamount=useamount)
stdList.add(std)
}while(cursor.moveToNext())
}
return stdList
}
fun updateStudent(std: StudentModel):Int{
val db = this.writableDatabase
val contentValues = ContentValues()
contentValues.put(ID,std.id)
contentValues.put(NAME,std.name)
contentValues.put(EMAIL,std.email)
contentValues.put(BUYAMOUNT, std.buyamount)
contentValues.put(USEAMOUNT,std.useamount)
val success = db.update(TBL_STUDENT,contentValues,"id="+std.id,null)
db.close()
return success
}
fun deleteStudentById(id:Int):Int{
val db = this.writableDatabase
val contentValues = ContentValues()
contentValues.put(ID,id)
val success = db.delete(TBL_STUDENT,"id=$id",null)
db.close()
return success
}
}
学生模型class
package com.example.sqlitedemo
import java.util.*
data class StudentModel(
var id: Int=getAutoId(),
var name: String = "",
var email: String = "",
var buyamount: Int = 0,
var useamount: Int=0
){
companion object{
fun getAutoId():Int{
val random = Random()
return random.nextInt(100)
}
}
}
我尝试了所有方法，但仍然不知道哪里出错了。有什么建议或解决方案吗？
抱歉代码布局不一致，我是堆栈溢出的新手。
问题是TextView的setText方法有多个实现，
public final void setText(@StringRes int resid) {
// ...
}
public final void setText(CharSequence text) {
// ...
}
而你的student模型的buyamount和useamount是int类型
所以，当你调用TextView的setText时，系统会调用setText(Int)而不是setText(CharSequence)。
setText(Int)会使用int参数作为资源id来获取字符串资源。当找不到给定id的资源时，会抛出异常。
要解决此问题，请尝试将 buyamount 和 useamount 转换为字符串，然后再将它们设置到 TextView。例如，
edBuyAmount.setText("" + it.buyamount)
edUseAmount.setText("" + it.useamount)
我正在尝试使用 kotlin 语言在 Android studio 中将 int 值实现到我的简单 sqlite 程序中。
我是 Kotlin 的初学者，所以我首先只使用字符串制作了一个 sqlite 程序，但现在我想使用 Int 值。
我设法使值成为 int 并插入工作正常，但是在选择记录时，应用程序崩溃。
这是日志猫。
15115-15115/com.example.sqlitedemo E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.sqlitedemo, PID: 15115
android.content.res.Resources$NotFoundException: String resource ID #0x3
at android.content.res.Resources.getText(Resources.java:444)
at android.widget.TextView.setText(TextView.java:6412)
at com.example.sqlitedemo.MainActivity$onCreate.invoke(MainActivity.kt:49)
错误 kt 49 和 44：与
有关 adapter?.setOnClickItem {
Toast.makeText(this,it.name,Toast.LENGTH_SHORT).show()
//レコード更新
edName.setText(it.name)
edEmail.setText(it.email)
edBuyAmount.setText(it.buyamount)
edUseAmount.setText(it.useamount)
std = it
}
at com.example.sqlitedemo.MainActivity$onCreate.invoke(MainActivity.kt:44)
at com.example.sqlitedemo.StudentAdapter.onBindViewHolder$lambda-0(StudentAdapter.kt:32)
错误 kt:32 与
有关override fun onBindViewHolder(holder: StudentViewHolder, position: Int) {
val std = stdList[position]
holder.bindView(std)
holder.itemView.setOnClickListener{onClickItem?.invoke(std)}
holder.btnDelete.setOnClickListener{onClickDeleteItem?.invoke(std)}
}
at com.example.sqlitedemo.StudentAdapter.$r8$lambda$rFSStv71TK0PX1i3mffPAEhmz7s(Unknown Source:0)
at com.example.sqlitedemo.StudentAdapter$$ExternalSyntheticLambda1.onClick(Unknown Source:4)
at android.view.View.performClick(View.java:7448)
at android.view.View.performClickInternal(View.java:7425)
at android.view.View.access00(View.java:810)
at android.view.View$PerformClick.run(View.java:28305)
at android.os.Handler.handleCallback(Handler.java:938)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:223)
at android.app.ActivityThread.main(ActivityThread.java:7656)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
MainActivity class()
class MainActivity : AppCompatActivity() {
private lateinit var edName: EditText
private lateinit var edEmail: EditText
private lateinit var edBuyAmount:EditText
private lateinit var edUseAmount:EditText
private lateinit var btnAdd: Button
private lateinit var btnView: Button
private lateinit var btnUpdate: Button
private lateinit var sqLiteHelper: SQLiteHelper
private lateinit var recyclerView: RecyclerView
private var adapter: StudentAdapter?=null
private var std:StudentModel?=null
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
initView()
initRecyclerView()
sqLiteHelper= SQLiteHelper(this)
//Show recycler view
val stdList = sqLiteHelper.getAllStudent()
Log.e("ok","${stdList.size}")
adapter?.addItems(stdList)
btnAdd.setOnClickListener{ addStudent()}
btnView.setOnClickListener{getStudents()}
btnUpdate.setOnClickListener{updateStudent()}
adapter?.setOnClickItem {
Toast.makeText(this,it.name,Toast.LENGTH_SHORT).show()
//data update
edName.setText(it.name)
edEmail.setText(it.email)
edBuyAmount.setText(it.buyamount)
edUseAmount.setText(it.useamount)
std = it
}
adapter?.setOnClickDeleteItem{
deleteStudent(it.id)
}
}
private fun deleteStudent(id:Int){
val builder = AlertDialog.Builder(this)
builder.setMessage("do you want to delete?")
builder.setCancelable(true)
builder.setNegativeButton("no"){dialog, _ ->
dialog.dismiss()
}
builder.setPositiveButton("yes"){dialog, _ ->
sqLiteHelper.deleteStudentById(id)
getStudents()
dialog.dismiss()
}
val alert = builder.create()
alert.show()
}
private fun updateStudent(){
val name = edName.text.toString()
val email = edEmail.text.toString()
val buyAmount = edBuyAmount.text.toString().toInt()
val useAmount = edUseAmount.text.toString().toInt()
//Check record not changed
if(name == std?.name && email == std?.email && buyAmount == std?.buyamount && useAmount == std?.useamount){
Toast.makeText(this,"Data wasnt updated",Toast.LENGTH_SHORT).show()
return
}
if(std == null) return
val std = StudentModel(id=std!!.id,name = name,email = email, buyamount = buyAmount, useamount = useAmount )
val status = sqLiteHelper.updateStudent(std)
if(status > -1){
clearEditText()
getStudents()
}else{
Toast.makeText(this,"error",Toast.LENGTH_SHORT).show()
}
}
private fun getStudents(){
val stdList = sqLiteHelper.getAllStudent()
Log.e("ok","${stdList.size}")
adapter?.addItems(stdList)
}
private fun addStudent(){
val name = edName.text.toString()
val email = edEmail.text.toString()
val buyAmount = edBuyAmount.text.toString().toInt()
val useAmount = edUseAmount.text.toString().toInt()
if(name.isEmpty()||email.isEmpty()|| buyAmount.toString().isEmpty() ||useAmount.toString().isEmpty()){
Toast.makeText(this,"enter data",Toast.LENGTH_SHORT).show()
}else{
val std = StudentModel(name = name, email=email, buyamount=buyAmount, useamount=useAmount)
val status = sqLiteHelper.insertStudent(std)
//Check Insert success or not success
if(status > -2){
Toast.makeText(this,"added data",Toast.LENGTH_SHORT).show()
clearEditText()
}else{
Toast.makeText(this,"data is not found。",Toast.LENGTH_SHORT).show()
}
}
}
private fun clearEditText(){
edName.setText("")
edEmail.setText("")
edBuyAmount.setText("")
edUseAmount.setText("")
edName.requestFocus()
}
private fun initRecyclerView(){
recyclerView.layoutManager=LinearLayoutManager(this)
adapter = StudentAdapter()
recyclerView.adapter=adapter
}
private fun initView(){
edName = findViewById(R.id.edName)
edEmail = findViewById(R.id.edEmail)
edBuyAmount=findViewById(R.id.edBuyAmount)
edUseAmount=findViewById(R.id.edUseAmount)
btnAdd = findViewById(R.id.btnAdd)
btnView = findViewById(R.id.btnView)
btnUpdate=findViewById(R.id.btnUpdate)
recyclerView=findViewById(R.id.recyclerView)
}
}
记录适配器class
class StudentAdapter: RecyclerView.Adapter<StudentAdapter.StudentViewHolder>() {
private var stdList: ArrayList<StudentModel> = ArrayList()
private var onClickItem: ((StudentModel) -> Unit)?=null
private var onClickDeleteItem: ((StudentModel) -> Unit)?=null
fun addItems(items: ArrayList<StudentModel>){
this.stdList=items
notifyDataSetChanged()
}
fun setOnClickItem(callback:(StudentModel)->Unit){
this.onClickItem = callback
}
fun setOnClickDeleteItem(callback: (StudentModel) -> Unit){
this.onClickDeleteItem = callback
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int)= StudentViewHolder (
LayoutInflater.from(parent.context).inflate(R.layout.card_items_rec,parent,false)
)
override fun onBindViewHolder(holder: StudentViewHolder, position: Int) {
val std = stdList[position]
holder.bindView(std)
holder.itemView.setOnClickListener{onClickItem?.invoke(std)}
holder.btnDelete.setOnClickListener{onClickDeleteItem?.invoke(std)}
}
override fun getItemCount(): Int {
return stdList.size
}
class StudentViewHolder(var view: View):RecyclerView.ViewHolder(view){
private var id = view.findViewById<TextView>(R.id.tvId)
private var name = view.findViewById<TextView>(R.id.tvName)
private var email = view.findViewById<TextView>(R.id.tvEmail)
private var buyAmount = view.findViewById<TextView>(R.id.tvBuyAmount)
private var useAmount = view.findViewById<TextView>(R.id.tvUseAmount)
var btnDelete = view.findViewById<TextView>(R.id.deleteBtn)
fun bindView(std:StudentModel){
id.text = std.id.toString()
name.text = std.name
email.text = std.email
buyAmount.text = std.buyamount.toString()
useAmount.text = std.useamount.toString()
}
}
}
学生数据库class
class SQLiteHelper(context:Context):SQLiteOpenHelper(context,DATABASE_NAME,null,DATABASE_VERSION){
companion object{
private const val DATABASE_VERSION =1
private const val DATABASE_NAME ="student.db"
private const val TBL_STUDENT = "tblRecords"
private const val ID ="[id]"
private const val NAME ="[name]"
private const val EMAIL ="[email]"
private const val BUYAMOUNT ="[buyamount]"
private const val USEAMOUNT ="[useamount]"
}
override fun onCreate(db: SQLiteDatabase?) {
val createTblStudent = ("CREATE TABLE "+ TBL_STUDENT + "("
+ ID + " INTEGER PRIMARY KEY,"+ NAME +" TEXT,"+
EMAIL +" TEXT,"+ BUYAMOUNT +" INTEGER,"+ USEAMOUNT +" INTEGER"+")")
db?.execSQL(createTblStudent)
}
override fun onUpgrade(db: SQLiteDatabase?, oldVersion: Int, newVersion: Int) {
db!!.execSQL("DROP TABLE IF EXISTS $TBL_STUDENT")
onCreate(db)
}
fun insertStudent(std: StudentModel): Long {
val db = this.writableDatabase
val contentValues = ContentValues()
contentValues.put(ID, std.id)
contentValues.put(NAME, std.name)
contentValues.put(EMAIL, std.email)
contentValues.put(BUYAMOUNT,std.buyamount)
contentValues.put(USEAMOUNT,std.useamount)
val success = db.insert(TBL_STUDENT,null,contentValues)
db.close()
return success
}
fun getAllStudent():ArrayList<StudentModel>{
val stdList: ArrayList<StudentModel> = ArrayList()
val selectQuery = "SELECT * FROM $TBL_STUDENT"
val db = this.readableDatabase
val cursor: Cursor?
try {
cursor = db.rawQuery(selectQuery,null)
}catch (e:Exception){
e.printStackTrace()
db.execSQL(selectQuery)
return ArrayList()
}
var id: Int
var name: String
var email: String
var buyamount: Int
var useamount: Int
if(cursor.moveToFirst()){
do{
id = cursor.getInt(cursor.getColumnIndexOrThrow("id"))
name = cursor.getString(cursor.getColumnIndexOrThrow("name"))
email = cursor.getString(cursor.getColumnIndexOrThrow("email"))
buyamount = cursor.getString(cursor.getColumnIndexOrThrow("buyamount")).toInt()
useamount = cursor.getString(cursor.getColumnIndexOrThrow("useamount")).toInt()
val std = StudentModel(id = id,name = name,email=email,buyamount=buyamount,useamount=useamount)
stdList.add(std)
}while(cursor.moveToNext())
}
return stdList
}
fun updateStudent(std: StudentModel):Int{
val db = this.writableDatabase
val contentValues = ContentValues()
contentValues.put(ID,std.id)
contentValues.put(NAME,std.name)
contentValues.put(EMAIL,std.email)
contentValues.put(BUYAMOUNT, std.buyamount)
contentValues.put(USEAMOUNT,std.useamount)
val success = db.update(TBL_STUDENT,contentValues,"id="+std.id,null)
db.close()
return success
}
fun deleteStudentById(id:Int):Int{
val db = this.writableDatabase
val contentValues = ContentValues()
contentValues.put(ID,id)
val success = db.delete(TBL_STUDENT,"id=$id",null)
db.close()
return success
}
}
学生模型class
package com.example.sqlitedemo
import java.util.*
data class StudentModel(
var id: Int=getAutoId(),
var name: String = "",
var email: String = "",
var buyamount: Int = 0,
var useamount: Int=0
){
companion object{
fun getAutoId():Int{
val random = Random()
return random.nextInt(100)
}
}
}
我尝试了所有方法，但仍然不知道哪里出错了。有什么建议或解决方案吗？
抱歉代码布局不一致，我是堆栈溢出的新手。
问题是TextView的setText方法有多个实现，
public final void setText(@StringRes int resid) {
// ...
}
public final void setText(CharSequence text) {
// ...
}
而你的student模型的buyamount和useamount是int类型
所以，当你调用TextView的setText时，系统会调用setText(Int)而不是setText(CharSequence)。
setText(Int)会使用int参数作为资源id来获取字符串资源。当找不到给定id的资源时，会抛出异常。
要解决此问题，请尝试将 buyamount 和 useamount 转换为字符串，然后再将它们设置到 TextView。例如，
edBuyAmount.setText("" + it.buyamount)
edUseAmount.setText("" + it.useamount)