Error while selecting radio buttons after creating dynamic UI in Android

Question

Hello to everyone i am creating a quiz app in which I am creating a dynamic UI for multiple choice question it Works well but when i select radio button on question and then go for next question and select the radio button i gives me error "java.lang.ClassCastException: android.widget.TextView cannot be cast to android.widget.RadioButton" Also when i change the selected option Example : First i choose option 1 of a question and then i change it to Option 2 it give me the same error Here is the sample of my code

 for(int i=1;i<=5;i++){
            TextView tv=new TextView(this);
            tv.setId(i);
            RadioGroup radioGroup=new RadioGroup(this);
            for(int j=0;j<=3;j++){

                RadioButton b1=new RadioButton(this);
                b1.setText("option"+j);
                b1.setId(j);
                radioGroup.addView(b1);

            }
            tv.setText("Youre question No "+i);
            tv.setTypeface(null, Typeface.BOLD);
            tv.setTextColor(Color.BLACK);
            radioGroup.setOrientation(RadioGroup.VERTICAL);
            tv.setPadding(20,0,0,0);
           radioGroup.setPadding(0,5,0,0);
            linearLayout.addView(tv);
            linearLayout.addView(radioGroup);
            radioGroup.setOnCheckedChangeListener(this);
        }

    }

    @Override
    public void onCheckedChanged(RadioGroup radioGroup, int i) {


        if (radioGroup.getCheckedRadioButtonId() != -1) {
            RadioButton uans = findViewById(radioGroup.getCheckedRadioButtonId());//Error occurred here
            String ansText = uans.getText().toString();
            answersStringArray.add(ansText);
        }
    }

Here is the Exception :

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.quizapp, PID: 3428
    java.lang.ClassCastException: android.widget.TextView cannot be cast to android.widget.RadioButton
        at com.example.quizapp.Paper.onCheckedChanged(Paper.java:99)//This shows where is the error
        at android.widget.RadioGroup.setCheckedId(RadioGroup.java:196)
        at android.widget.RadioGroup.access$600(RadioGroup.java:59)
        at android.widget.RadioGroup$CheckedStateTracker.onCheckedChanged(RadioGroup.java:381)
        at android.widget.CompoundButton.setChecked(CompoundButton.java:183)
        at android.widget.CompoundButton.toggle(CompoundButton.java:135)
        at android.widget.RadioButton.toggle(RadioButton.java:76)
        at android.widget.CompoundButton.performClick(CompoundButton.java:140)
        at android.view.View.performClickInternal(View.java:7218)
        at android.view.View.access$3800(View.java:824)
        at android.view.View$PerformClick.run(View.java:27719)
        at android.os.Handler.handleCallback(Handler.java:883)
        at android.os.Handler.dispatchMessage(Handler.java:100)
        at android.os.Looper.loop(Looper.java:228)
        at android.app.ActivityThread.main(ActivityThread.java:7782)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:981)

How can i overcome this please help me guys thanks in advance

score 1 · Accepted Answer · answered Sep 07 '20 at 08:27

1

tv.setId(i); and b1.setId(j); - don't do that... you shouldn't use/set ids like this. all Views ids should (must?) be unique in whole app and in your case one TextView and few RadioButton may have same id (e.g. 1). check out THIS SO topic for more info how to set properly ids for Views programmatically

you are setting id with small int for both TextView and RadioButton, so when you call findViewById it will return first found View with this id - in your case TextView, but you are casting it to RadioButton...

answered Sep 07 '20 at 08:27

snachmsm

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what can i do to resolve this issue then should i enter some string along side with the id – Kaushal Digraskar Sep 07 '20 at 08:31
change ids, they are duplicated. easiest way: `b1.setId(j);` -> `b1.setId(i*100+j);`, but this isn't good way, read topic linked in answer – snachmsm Sep 07 '20 at 08:32
@snachsm thank you sir youre answer helped me alot now i am using View.generateViewId() and its helps me well – Kaushal Digraskar Sep 07 '20 at 08:42

Error while selecting radio buttons after creating dynamic UI in Android

1 Answers1