MixedCompoundButtonGroup resolve the one and only selected button in CompoundButton (CheckBox, RadioButton, Switch, ToggleButton) group

activity_compound_button_group.xml

<?xml version="1.0" encoding="utf-8"?>
<your.project.package.MixedCompoundButtonGroup xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/mixedCompoundButtonGroup_container"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <RadioButton
        android:id="@+id/rb1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="aaa"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <RadioButton
        android:id="@+id/rb2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="bbb"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <RadioButton
        android:id="@+id/rb3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="ccc"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@id/rb1" />


    <LinearLayout
        android:id="@+id/ll_radioGroup_container1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/toggleButton">

        <RadioButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="AAA" />

        <RadioButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="BBB" />

        <RadioButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="CCC" />
    </LinearLayout>

    <Switch
        android:id="@+id/btn_switch1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="20dp"
        app:layout_constraintTop_toBottomOf="@id/rb1" />

    <ToggleButton
        android:id="@+id/toggleButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:layout_constraintTop_toBottomOf="@id/btn_switch1" />


</your.project.package.MixedCompoundButtonGroup>

CompoundButtonGroupActivity.kt

package your.project.package

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.CompoundButton
import android.widget.Toast
import your.project.package.R

class CompoundButtonGroupActivity : AppCompatActivity() {
    private lateinit var mixedCompoundButtonGroup: MixedCompoundButtonGroup
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_compound_button_group)
        mixedCompoundButtonGroup = findViewById(R.id.mixedCompoundButtonGroup_container)
        mixedCompoundButtonGroup.setOnCheckedChangeListener(object : OnCheckedChangeListener {
            override fun onCheckedChanged(compoundButton: CompoundButton) {
                Toast.makeText(applicationContext, "checkedId = ${compoundButton.id}", Toast.LENGTH_SHORT).show()
            }
        })
    }

    override fun onDestroy() {
        mixedCompoundButtonGroup.setOnCheckedChangeListener(null)
        super.onDestroy()
    }
}

MixedCompoundButtonGroup.kt

package your.project.package

import android.content.Context
import android.util.AttributeSet
import android.view.View
import android.view.ViewGroup
import android.widget.CompoundButton
import android.widget.RadioGroup
import androidx.constraintlayout.widget.ConstraintLayout

/**
 * Created by Avishay.Peretz on 10/12/2019.
 */
class MixedCompoundButtonGroup @JvmOverloads constructor(
        context: Context, attrs: AttributeSet? = null, defStyleAttr: Int = 0
) : ConstraintLayout(context, attrs, defStyleAttr) {

    private var currentCompoundButton: CompoundButton? = null

    private lateinit var compoundButtonCheckedChangedListener: CompoundButton.OnCheckedChangeListener

    private var checkedChangedListener: OnCheckedChangeListener? = null

    init {
        initCompoundButtonListener()
    }

    private fun initCompoundButtonListener() {
        compoundButtonCheckedChangedListener = CompoundButton.OnCheckedChangeListener { compoundButton, isChecked ->
            setChecked(compoundButton, isChecked)
        }
    }

    private fun setChecked(compoundButton: CompoundButton, isChecked: Boolean) {
        if (isChecked.not()) return
        if (currentCompoundButton != null) {
            currentCompoundButton!!.isChecked = false
            currentCompoundButton = compoundButton
        } else {
            currentCompoundButton = compoundButton
        }
        checkedChangedListener?.onCheckedChanged(currentCompoundButton!!)
    }

    override fun addView(child: View?, index: Int, params: ViewGroup.LayoutParams?) {
        super.addView(child, index, params)
        setCompoundButtonListener(child)
    }

    private fun setCompoundButtonListener(view: View?) {
        if (view == null) return
        if (view is CompoundButton) {
            view.setOnCheckedChangeListener(compoundButtonCheckedChangedListener)
        } else if (view is ViewGroup && view !is RadioGroup) { // NOT RadioGroup!
            for (i in 0 until view.childCount) {
                setCompoundButtonListener(view.getChildAt(i))
            }
        }
    }

    fun setOnCheckedChangeListener(onCheckedChangeListener: OnCheckedChangeListener?) {
        checkedChangedListener = onCheckedChangeListener
    }

}

interface OnCheckedChangeListener {
    fun onCheckedChanged(compoundButton: CompoundButton)
}

#Android #Kotlin #CompoundButton #CheckBox #RadioButton #Switch #ToggleButton

git repo: https://github.com/avisper/EasyCompoundButtonGroup