CODEWITHSUNDEEP
androidandroid-databinding
me.at.coding
me.at.coding

Reputation: 17754

Explicitely define Binding Adapter to be used?

In Android, the mapping between attributes (like android:text) and the corresponding data binding adapter is done by the binding adapter annotation containing the same attribute name (like @BindingAdapter("android:text")).

So, if I want a data binding adapter from Double to String, do I have to use a custom attribute or is it possible to stick with android:text and in addition specify something like android:useCustomBindingAdapter="my.double.to.string.bindingadapter"?

Upvotes: 0

Views: 636

Answers (2)

Yrii Borodkin
Yrii Borodkin

Reputation: 782

I think you can create static converting method and inverse adapter.

Create methods in some file/class, like 

@file:JvmName("DoubleToStringConverter")

package com.test.android

fun doubleToString(view: EditText, num: Double) = num.toString()

@InverseMethod("doubleToString")
fun textToDouble(view: EditText, value: CharSequence): Double { 
return value.toString().toDouble() }

and then in you layout

layout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto">

    <data>
        <import type="com.test.android.DoubleToStringConverter"/>
    </data>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">

        <TextView
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:text="@={DoubleToStringConverter.doubleToString(your_viewmodel_live_data)}"
             />
</LinearLayout>

Upvotes: 1

Haris Kurbardovic
Haris Kurbardovic

Reputation: 1

If you want to bind a double add this code snippet:

@BindingAdapter("android:text")
fun bindToText(view: TextView, value: Double?) {
value?.let {
    view.text = value.toString()
    }
}

If you want to support multiple types:

@BindingAdapter("android:text")
fun bindToText(view: TextView, value: Any?) {
    value?.let {
        when (value) {
            is Double -> view.text = String.format(Locale.getDefault(), "%.2f", value)
            is Int -> view.text = value.toString()
        }
    }
}

Upvotes: 0

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