Android:get value from Radiobutton

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Android:get value from Radiobutton

Asked 9 years, 1 month ago

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Hi, I have a problem I can’t solve. I have a dialog where I have a RadioGroup with 2 Radio Buttons and a button OK.

I want to get the radio button value selected when I click OK, but I’m getting the Exception "java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.CharSequence android.widget.RadioButton.getText()' on a null object reference".

The code is as follows::

public void test(){


    final Dialog dialog = new Dialog(this);
    dialog.setContentView(R.layout.activity_currency);
    dialog.setTitle("Test");
    dialog.show();

    //selected=new RadioButton(this.getApplicationContext());
    radioG = (RadioGroup) dialog.findViewById(R.id.radioGroup);

    Button ok = (Button) dialog.findViewById(R.id.buttonOk);
    ok.setOnClickListener(new View.OnClickListener() {


        @Override
        public void onClick(View v) {

            // get selected radio button from radioGroup
            int selectedId = radioG.getCheckedRadioButtonId();

            Log.d("Base ACtivity","selectedId:"+selectedId);

            // find the radiobutton by returned id
            selected = (RadioButton) findViewById(selectedId);

            String a = selected.getText().toString();

            String optionSelected = ((RadioButton) v).getText().toString();
        }
    });
}

The problem is on the line String a = selected.getText().toString()); . I have by default a radiobutton selected in the XML file via android:checked="true", what makes it selectedId never be null.

I wonder if they could help?

The error will not be on the line String optionSelected = ((RadioButton) v).getText().toString();? Note that v is a button and you’re doing the cast for Radiobutton

– ramaral

2015/05/24 at 09:56
@ramaral, yes the error is there, the v is a button?

– porthfind

2015/05/24 at 19:26
It is because the Onclicklistener, in this case, it has been associated with a button: ok.setOnClickListener(new View.OnClickListener()....

– ramaral

2015/05/24 at 20:12
@ramaral not realizing.. was associated with the ok button, because I want when you click the ok button, get the value of the radiobutton

– porthfind

2015/05/24 at 20:23
Yes that’s correct, however v is a button. I will put an answer.

– ramaral

2015/05/24 at 20:32
No need to put answer, comment or delete the line String optionSelected = ((RadioButton) v).getText().toString(); the text of Radiobutton selected is in the string a

– ramaral

2015/05/24 at 21:01
@ramaral problem is even in line String a = Selected.gettext(). toString();

– porthfind

2015/05/25 at 14:31
When you said you were going to post an answer, it was because you thought your code might have a problem. I did some tests and found nothing wrong. However I took the principle that radioG is a Radiogroup and that has a Radiobutton selected. What is written in log by line Log.d("Base ACtivity","selectedId:"+selectedId);?

– ramaral

2015/05/25 at 14:38
@ramaral, selectedId:2131296322

– porthfind

2015/05/25 at 14:39

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by ramaral • **44,197** points · Answer 1 · 2015-05-25T14:48:26+00:00

The problem is you’re using the method findViewById() of Activity and not of Radiogroup.
The method seeks a View with that id in Activity as she does not have it he returns null.

Change the line:

selected = (RadioButton) findViewById(selectedId);

for

selected = (RadioButton) radioG.findViewById(selectedId);