Issue in adding new value in ArrayList at 0th position

Issue

I have ArrayList of my model/pojo class. Which has below values which I am getting in my logcat :

BatteryDetailsHistory(dates=10 01 2022, dateNumber=10, chargeOverTime=94, avgTemperature=21.9385, averageChargeDischarge=-2.1234)

Now, here at specific situation I have to add one value of the object BatteryDetailsHistory at 0th position in the arraylist of this model/pojo.

So, I have done it as below :

var objNew = list[0]
objNew.averageChargeDischarge = "0"
list.add(0, objNew)

But after that What I am getting is as below :

BatteryDetailsHistory(dates=10 01 2022, dateNumber=10, chargeOverTime=94, avgTemperature=21.9385, averageChargeDischarge=0)

BatteryDetailsHistory(dates=10 01 2022, dateNumber=10, chargeOverTime=94, avgTemperature=21.9385, averageChargeDischarge=0)

You can see I have tried changing the value of averageChargeDischarge to 0 But after adding new object of pojo/model to my list, I am getting both the data in list with values 0 for averageChargeDischarge

What might be the issue ?

Solution

If you want just change a property of the first object in the list, you can access it by index:

 list[0].averageChargeDischarge = "0"

If you want to preserve the first object with its initial data in the list, then you need to make a copy of it, e.g. create a new object:

// If object(BatteryDetailsHistory) is a data class
val objNew = list[0].copy(averageChargeDischarge = "0")
list.add(0, objNew)

// If object(BatteryDetailsHistory) is not a data class
val objOld = list[0]
val objNew = BatteryDetailsHistory(/*copy all properties from objOld*/, averageChargeDischarge = "0")
list.add(0, objNew)

Answered By - Sergey