如何以编程方式检查动态广播组中的单选按钮？

Question

I have a list of radio buttons. I want one to be selected when the application first launch.

Then when I will select some other radio button from the radio group that will be deselected.

Here's my code:

for (x in taskTypes) {
        var radioButton = RadioButton(context)
        radioButton.setOnCheckedChangeListener { button: CompoundButton?, b: Boolean  ->
            if (b) {
                ......

            }
        }

        taskRadioGroup.addView(radioButton)
    }

Answer 1

If you use radioGroup , previously selected radioButton should be automatically deselected. If you want a particular radioButton to be selected when activity is launched you have just have to add the following line in onCreate() :

yourDesiredRadioButton.isChecked = true;

Answer 2

You can use setTag(); method to provide a unique identification for all the buttons in your group and check/change the properties by checking their tags using getTag()

Answer 3

If you want to select the first RadioButton to be selected you can do this:

var isChecked = true;

for (x in taskTypes) {
    var radioButton = RadioButton(context)

    if(isChecked){
        isChecked = false;
        radioButton.checked = true;
     }

    taskRadioGroup.addView(radioButton)
}

 taskRadioGroup.setOnCheckedChangeListener { button: CompoundButton?, b: Boolean  ->
        if (b) {
            ......

        }
    }

Answer 4

I want one to be selected when the application first launch

On create method

 hardradioButton!!.isChecked = true

make listener of your radioGroup On create method

 radioGroup!!.setOnCheckedChangeListener(this)

implement OnCheckedChangeListener

override fun onCheckedChanged(group: RadioGroup, checkedId: Int) {
        when (checkedId) {
            R.id.hard_radiobuttonm -> {
                //do whatever
            }

            R.id.ok_radiobuttonm -> {
               //do whatever
            }

            R.id.easy_radiobuttonm -> {
               //do whatever
            }


            else -> {
            }
        }

    }

Answer 5

I'm not sure why it always check the first RadioButton even when ALL radio is added inside a RadioGroup. My test also confirm your bug (maybe not bug, I just not sure why).

Here's my solution to your problem:

var radioGroup = RadioGroup(applicationContext)

for (i: Int in 0..4){
    var radio = RadioButton(applicationContext)
    radio.setText("button position ${i+1}")

    radioGroup.addView(radio)
    Log.d("LOG", "Working on radio ${i+1}")
}

radioGroup.check(0)

linearParent.addView(radioGroup)

Noticed how I set the first radio by executing check(0) of the radioGroup . This is because whenever I set if from the radio itself, that radio will always be in checked state:

//this code I placed inside for loop is somewhat broken...
if(i == 0){
    radio.isChecked = true
}