Android NumberPicker: Set min, max, default from XML

Question

Is there a way to set the minimum, maximum and default values of a NumberPicker from the XML Layout?

I\'m doing it from within the Activity code:

np          


        

Answer 1

Here is an updated version that follows the Android Docs
(and thus supports theming & Android Studio designer preview)

values/attrs.xml:

NumberPickerWithXml.kt:

package com.example.library.ui

import android.content.Context
import android.util.AttributeSet
import android.widget.NumberPicker
import com.example.library.ui.R

class NumberPickerWithXml : NumberPicker {

    constructor(context: Context) : super(context)

    constructor(context: Context, attrs: AttributeSet) : super(context, attrs) {
        processXmlAttributes(attrs)
    }

    constructor(context: Context, attrs: AttributeSet, defStyleAttr: Int) : super(context, attrs, defStyleAttr) {
        processXmlAttributes(attrs, defStyleAttr)
    }

    constructor(context: Context, attrs: AttributeSet, defStyleAttr: Int, defStyleRes: Int) : super(context, attrs, defStyleAttr, defStyleRes) {
        processXmlAttributes(attrs, defStyleAttr, defStyleRes)
    }

    private fun processXmlAttributes(attrs: AttributeSet, defStyleAttr: Int = 0, defStyleRes: Int = 0) {
        val attributes = context.theme.obtainStyledAttributes(attrs, R.styleable.NumberPickerWithXml, defStyleAttr, defStyleRes)

        try {
            this.minValue = attributes.getInt(R.styleable.NumberPickerWithXml_minValue, 0)
            this.maxValue = attributes.getInt(R.styleable.NumberPickerWithXml_maxValue, 0)
            this.value = attributes.getInt(R.styleable.NumberPickerWithXml_defaultValue, 0)
        } finally {
            attributes.recycle()
        }
    }

}

...or NumberPickerWithXml.java (untested):

package com.example.library.ui

import android.content.Context
import android.util.AttributeSet
import android.widget.NumberPicker
import com.example.library.ui.R

public class NumberPickerWithXml extends NumberPicker {

    public NumberPickerWithXml(Context context) {
        super(context);
    }

    public NumberPickerWithXml(Context context, AttributeSet: attrs) {
        super(context, attrs);
        processXmlAttributes(attrs, 0, 0);
    }

    public NumberPickerWithXml(Context context, AttributeSet: attrs, int: defStyleAttr) {
        super(context, attrs, defStyleAttr);
        processXmlAttributes(attrs, defStyleAttr, 0);
    }

    public NumberPickerWithXml(Context context, AttributeSet: attrs, int: defStyleAttr, int: defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
        processXmlAttributes(attrs, defStyleAttr, defStyleRes);
    }

    private void processXmlAttributes(AttributeSet: attrs, int: defStyleAttr, int: defStyleRes) {
        TypedArray attributes = context.getTheme().obtainStyledAttributes(attrs, R.styleable.NumberPickerWithXml, defStyleAttr, defStyleRes)

        try {
            this.minValue = attributes.getInt(R.styleable.NumberPickerWithXml_minValue, 0);
            this.maxValue = attributes.getInt(R.styleable.NumberPickerWithXml_maxValue, 0);
            this.value = attributes.getInt(R.styleable.NumberPickerWithXml_defaultValue, 0);
        } finally {
            attributes.recycle();
        }
    }

}

Usage in your layout: