如何将ROOM数据库的列与编辑文本相乘 [英] How to multiplicate ROOM database's columns with edit text

问题描述

我有一个问题，是否可以选择使用适配器中的可编辑文本从ROOM中的列计算数据?适配器:

I have a question if there is any option to calculate data from column in ROOM with editable Edit Text in adapter? Adapter:

class AdapterList (context: Context, val resource: Int, val objects: List<Opryski>) :
    ArrayAdapter<Opryski>(context, resource, objects){
override fun getView(position: Int, convertView: View?, parent: ViewGroup): View {
    val inflater = LayoutInflater.from(context)
    val customView = inflater.inflate(resource, parent, false)
    val area= customView.findViewById<EditText>(R.id.editTextSize)
    val dose= customView.findViewById<TextView>(R.id.id_dose)
    val name= customView.findViewById<TextView>(R.id.id_nazme)
    val what= customView.findViewById<TextView>(R.id.id_what)
    val when= customView.findViewById<TextView>(R.id.id_when)
    val profilaktyka = customView.findViewById<TextView>(R.id.id_profilaktyka)

    val item = objects.getOrNull(position)
    if(item!=null)
    {
        name.text = item.name
        dose.text = item.dose.toString() * area //<--- I want to multiplicate this//
        what.text = item.what
        when.text = item.when
        profilaktyka.text = item.profilaktyka
    }
return customView
}

}

EditText在activity_main.xml中，是我们可以输入区域的位置，程序应显示该区域所需农药的计算剂量列表

EditText is in activity_main.xml as place where we can type our area and program should show a list of calculated dose of pesticide needed to this area

推荐答案

您需要通过查询来做到这一点，并且还需要一个中间模型来做到这一点:

You need to do it with a query and also have an intermediate Model for doing it so:

Room是SQLite的包装器，因此大多数在SQLite上有效的内容都对ROOM有效

Room is a SQLite wrapper, so mostly all valid on SQLite is valid for ROOM

//I'm using a raw string here, triple quotes so I can write without minding the line breaks
@Query("""SELECT 
name as name,
what as what,
when as when,
(dose * :area) as multiplication
FROM Opryski
""")
fun observeOpryskiesWithCalculatedDose(area: Int): LiveData<DosedOpryski>

因此您可以看到某物，这是因为我们要在 DosedOpryski

So as you can see there is something as something that is because we are going to reflect all those values in the DosedOpryski

data class DosedOpryski(
    val name: String, val what: String, val when: String, val multiplication: Int
)

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