Android SQLite Value must be ≥ 0 getColumnIndex Kotlin

Question

I am getting an error in Android Studio to do with my Cursor.

I have the following line in my code

val dataText = cursor.getString(cursor.getColumnIndex(MyDbNameClass.COLUMN_NAME_TITLE))

I tried using cursor.getColumnIndexOrThrow() but it didn't help I am new to android, hope you can help me. Here is my code.

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/tvTest"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <EditText
        android:id="@+id/edTitle"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:ems="10"
        android:inputType="textPersonName"
        android:text="Name"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.437"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.071" />

    <EditText
        android:id="@+id/edDesc"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:ems="10"
        android:inputType="textPersonName"
        android:text="Name"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.437"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.166" />

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="onClickSave"
        android:text="Button"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.498"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.796" />

</androidx.constraintlayout.widget.ConstraintLayout>

MainActivity.kt

package com.example.todo

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.view.View
import android.widget.EditText
import android.widget.TextView
import com.example.todo.db.MyDbManager

class MainActivity : AppCompatActivity() {

    val myDbManager = MyDbManager(this)

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
    }
    fun onClickSave(view: View) {
        val edTitle = findViewById<EditText>(R.id.edTitle)
        val edDesc = findViewById<EditText>(R.id.edDesc)
        val tvTest = findViewById<TextView>(R.id.tvTest)
        tvTest.text = ""
        myDbManager.openDb()
        myDbManager.insertToDb(edTitle.text.toString(), edDesc.text.toString())
        val dataList = myDbManager.readDbData()
        for (item in dataList) {
            tvTest.append(item)
            tvTest.append("\n")
        }
    }
    override fun onDestroy() { //при выходе с активити
        super.onDestroy()
        myDbManager.closeDb()
    }
}

MyDbNameClass.kt

package com.example.todo.db

import android.provider.BaseColumns

object MyDbNameClass: BaseColumns {
    const val TABLE_NAME = "info"
    const val COLUMN_NAME_TITLE = "title"
    const val COLUMN_NAME_DESC = "desc"

    const val DATABASE_VERSION = 1
    const val DATABASE_NAME = "ToDoDb.db"

    const val CREATE_TABLE = "CREATE TABLE $TABLE_NAME (" +
            "${BaseColumns._ID} INTEGER PRIMARY KEY, $COLUMN_NAME_TITLE TEXT, $COLUMN_NAME_DESC TEXT)"
    const val SQL_DELETE_TABLE = "DROP TABLE IF EXISTS $TABLE_NAME"
}

MyDbHelper.kt

package com.example.todo.db

import android.content.ContentValues
import android.content.Context
import android.database.Cursor
import android.database.sqlite.SQLiteDatabase
import android.database.sqlite.SQLiteOpenHelper
import android.provider.BaseColumns

class MyDbHelper(context: Context) : SQLiteOpenHelper(context, MyDbNameClass.DATABASE_NAME, null, MyDbNameClass.DATABASE_VERSION) {
    override fun onCreate(db: SQLiteDatabase?) {
        db?.execSQL(MyDbNameClass.CREATE_TABLE)
    }

    override fun onUpgrade(db: SQLiteDatabase?, oldVersion: Int, newVersion: Int) {
        db?.execSQL(MyDbNameClass.SQL_DELETE_TABLE)
        onCreate(db)
    }
}

MyDbManager.kt (error here)

package com.example.todo.db

import android.content.ContentValues
import android.content.Context
import android.database.sqlite.SQLiteDatabase

class MyDbManager(context: Context) {
    private val myDbHelper = MyDbHelper(context)
    private var db: SQLiteDatabase? = null

    fun openDb(){
        db = myDbHelper.writableDatabase
    }
    fun insertToDb(title: String, desc: String){
        val values = ContentValues().apply {
            put(MyDbNameClass.COLUMN_NAME_TITLE, title)
            put(MyDbNameClass.COLUMN_NAME_DESC, desc)
        }
        db?.insert(MyDbNameClass.TABLE_NAME, null, values)
    }

    fun readDbData() : ArrayList<String> {
        val dataList = ArrayList<String>()
        val cursor = db?.query(MyDbNameClass.TABLE_NAME, null, null,
            null, null, null, null)
        db?.rawQuery(MyDbNameClass.TABLE_NAME, null)
        var k = 1
        while (cursor?.moveToNext()!!){
            val dataText = cursor.getString(cursor.getColumnIndex(MyDbNameClass.COLUMN_NAME_TITLE))
            dataList.add(dataText.toString())
        }
        cursor.close()
        return dataList
    }
    fun closeDb(){
        myDbHelper.close()
    }
}

Answer 1

This is a warning

Value must be ≥ 0 but getColumnIndex can be -1

that indicates that in this method, the value of getColumnIndex(..) must be ≥ 0 , but it would be -1

getColumnIndex() Returns the zero-based index for the given column name, or -1 if the column doesn't exist. If you expect the column to exist use getColumnIndexOrThrow(String) instead, which will make the error more clear.

---

You have two options:

Use getColumnIndexOrThrow() instead of getColumnIndex()

getColumnIndexOrThrow() Returns the zero-based index for the given column name, or throws IllegalArgumentException if the column doesn't exist.

Disabling the warning using the the annotation:

    @SuppressLint("Range")

To disable this warning add the annotation @SuppressLint("Range") because the method getColumnIndex() requires a value in a particular numerical range ( ≥ 0) .

@SuppressLint("Range")
fun readDbData() : ArrayList<String> {
        val dataList = ArrayList<String>()
        val cursor = db?.query(MyDbNameClass.TABLE_NAME, null, null,
            null, null, null, null)
        db?.rawQuery(MyDbNameClass.TABLE_NAME, null)
        var k = 1
        while (cursor?.moveToNext()!!){
            val dataText = cursor.getString(cursor.getColumnIndex(MyDbNameClass.COLUMN_NAME_TITLE))
            dataList.add(dataText.toString())
        }
        cursor.close()
        return dataList
    }