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scorpions
Asked: 2021-11-22 09:55:52 +0800 CST 2021-11-22 09:55:52 +0800 CST

get data from a table from a SQLite Android database

  • 772

I'm making a small application in android with kotlin, I'm pretty new at this... I've already created the database, the table, I do the insert, but I would like to make a select from that table in an activity and show the data. .. I do not get it...

This is my code to get the users

//función para obtener usuarios
fun getUsers(): ArrayList<User> {
        val usuarios = ArrayList<User>()
        val db = writableDatabase
        val selectQuery = "SELECT  * FROM NOMBRE_TABLA"
        val cursor = db.rawQuery(selectQuery, null)
        if (cursor != null) {
            cursor.moveToFirst()
            while (cursor.moveToNext()) {
                val nombre  = cursor.getString(cursor.getColumnIndex(COL_NOMBRE))
                val apellidos  = cursor.getString(cursor.getColumnIndex(COL_APELLIDOS))
                val usuario = User(nombre, apellidos)
                usuarios.add(usuario)
            }
        }
        cursor.close()
    return usuarios
    }
}

I think it returns them correctly, but now I don't know how to return them to the view... This is my method in my activity

fun listado(){
    var db = Database(this, "pacDesarrollo", null, 1)
    db.getUsers()
}

I've managed not to fail me, but I don't know how I should show them...

I think I have found the solution to display them. a listView

but when trying to display my data there, the LogCat returns the following error:

java.lang.IllegalStateException: ArrayAdapter requires the resource ID to be a TextView

And since I am creating the adapter, it is:

fun listado() {
    var db = Database(this, "pacDesarrollo", null, 1)
    val users = db.getUsers()

    adaptador1 = ArrayAdapter(this, android.R.layout.activity_list_item, users)
    vista.setAdapter(adaptador1)
}

Thank you and regards

java

1 Answers

  1. Best Answer

    If you are going to use the layout of the "item" SDK you must do it in this way

    adaptador1  = new ArrayAdapter<String>(this, 
                                android.R.layout.simple_list_item_1,
                                users
                            );

    If you use a custom layout called activity_list_item, you will do it like this:

    adaptador1  = new ArrayAdapter<String>(this, 
                                R.layout.activity_list_item,
                                users
                            );
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