android checkbox getting java.lang.nullpointerexception while setchecked checkbox false

Question

I was really dizzy because of this problem, why i always getting java.lang.nullpointerexception while i try to set checkbox false, but when i set checkbox true , it is working normally.

this is my code

private int jlhChampion = 5;
private int jlhParticipant = 14;
private int jlhRegisterType = 4;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.detail_tournament);
    titleTournament = (TextView) findViewById(R.id.tournament_detail_title);
    descTournament = (TextView) findViewById(R.id.tournament_title_desc);
    titleTournament = (TextView) findViewById(R.id.tournament_detail_title);
    descTournament = (TextView) findViewById(R.id.tournament_title_desc);
    descStatusTournament = (TextView) findViewById(R.id.txt_tournament_detail_status_desc);
    layout_champion_tournament = (LinearLayout) findViewById(R.id.layout_champion_detail_tournament);
    layoutParticipant = (LinearLayout) findViewById(R.id.layout_participant_detail_status_desc);
    layoutRegistrationType = (LinearLayout) findViewById(R.id.layout_registration_type_tournament_detail);
    titleTournament.setText(tournamentTest);
    descStatusTournament.setText(tournamentDescStatusTest);
    initPastChampion();
    initPastParticipant();
    initRegistrationType();

}

private void initPastChampion() {
    if (jlhChampion != 0) {
        if (jlhChampion > 4) {
            jlhChampion = jlhChampion - (jlhChampion - 4);
        }
        for (int i = 0; i < jlhChampion; i++) {
            LayoutInflater inflater = (LayoutInflater) this
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            View view = inflater.inflate(
                    R.layout.tournament_participant_view, null);
            ((TextView) view
                    .findViewById(R.id.txt_title_status_participant))
                    .setText("Nama user" + i);
            ((TextView) view
                    .findViewById(R.id.txt_title_status_participant))
                    .setTextAppearance(getApplicationContext(),
                            R.style.text_sub_title_white_style);
            ((TextView) view
                    .findViewById(R.id.txt_description_status_participant))
                    .setText(detailChampion + " " + i);
            ((TextView) view
                    .findViewById(R.id.txt_description_status_participant))
                    .setTextAppearance(getApplicationContext(),
                            R.style.textContentWhite_style);
            Button b = ((Button) view
                    .findViewById(R.id.btn_view_profile_of_participant));
            b.setOnClickListener(clickButton);
            layout_champion_tournament.addView(view);
            b.setTag("Champion " + i);
        }
    } else {

    }
}

private void initPastParticipant() {
    if (jlhParticipant != 0) {
        if (jlhParticipant > 4) {
            jlhParticipant = jlhParticipant - (jlhParticipant - 4);
        }
        for (int i = 0; i < jlhParticipant; i++) {
            LayoutInflater inflater = (LayoutInflater) this
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            View view = inflater.inflate(
                    R.layout.tournament_participant_view, null);
            ((TextView) view
                    .findViewById(R.id.txt_title_status_participant))
                    .setText("Nama user" + " Participant " + i);
            ((TextView) view
                    .findViewById(R.id.txt_title_status_participant))
                    .setTextAppearance(getApplicationContext(),
                            R.style.text_sub_title_white_style);
            ((TextView) view
                    .findViewById(R.id.txt_description_status_participant))
                    .setText(registrationType + " " + i);
            ((TextView) view
                    .findViewById(R.id.txt_description_status_participant))
                    .setTextAppearance(getApplicationContext(),
                            R.style.textContentWhite_style);
            Button b = ((Button) view
                    .findViewById(R.id.btn_view_profile_of_participant));
            b.setOnClickListener(clickButton);
            layoutParticipant.addView(view);
            b.setTag("Participant " + i);

        }
    } else {

    }
}

private void initRegistrationType() {
    if (jlhRegisterType != 0) {
        for (int i = 0; i < jlhRegisterType; i++) {
            LayoutInflater inflater = (LayoutInflater) this
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            View view = inflater.inflate(R.layout.registration_type_item,
                    null);
            ((TextView) view
                    .findViewById(R.id.txt_title_status_participant))
                    .setText("Register " + i);
            ((TextView) view
                    .findViewById(R.id.txt_title_status_participant))
                    .setTextAppearance(getApplicationContext(),
                            R.style.text_sub_title_white_style);
            ((TextView) view
                    .findViewById(R.id.txt_description_of_registration_type))
                    .setText(detailChampion + " " + " Participant " + i);
            ((TextView) view
                    .findViewById(R.id.txt_description_of_registration_type))
                    .setTextAppearance(getApplicationContext(),
                            R.style.textContentWhite_style);
            CheckBox c = ((CheckBox) view
                    .findViewById(R.id.chk_register_type));
            c.setOnClickListener(clickButton);
            layoutRegistrationType.addView(view);
            c.setTag("RegistrationType " + i + " " + jlhRegisterType);
        }
    } else {

    }
}

OnClickListener clickButton = new OnClickListener() {

    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub
        String idxStr = (String) v.getTag();
        CheckBox checkRegistrationTypes;
        if (idxStr.startsWith("RegistrationType", 0)) {
            if(((CheckBox)v).isPressed()){
                String[] regType = idxStr.split(" ");
                String[] regTypes = new String[Integer.parseInt(regType[2])];
                for (int i = 0; i < regTypes.length; i++) {
                    checkRegistrationTypes = (CheckBox) v.findViewById(R.id.chk_register_type)
                            .findViewWithTag("RegistrationType " + i + " " + regTypes.length);

                    if(Integer.toString(i).equals(regType[1])){
                        checkRegistrationTypes.setChecked(true);
                    }else{
                        //this is the problem
                        checkRegistrationTypes.setChecked(false);
                    }
                }
            }
        }
    }
};

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.detail_tournament, menu);
    return true;
}

I got error like this

W/dalvikvm(2648): threadid=1: thread exiting with uncaught exception (group=0x40a71930)
 E/AndroidRuntime(2648): FATAL EXCEPTION: main
 E/AndroidRuntime(2648): java.lang.NullPointerException
 E/AndroidRuntime(2648):    at com.chess.DetailTournament$1.onClick(DetailTournament.java:194)
 E/AndroidRuntime(2648):    at android.view.View.performClick(View.java:4204)
 E/AndroidRuntime(2648):    at android.widget.CompoundButton.performClick(CompoundButton.java:100)
 E/AndroidRuntime(2648):    at android.view.View$PerformClick.run(View.java:17355)
 E/AndroidRuntime(2648):    at android.os.Handler.handleCallback(Handler.java:725)
 E/AndroidRuntime(2648):    at android.os.Handler.dispatchMessage(Handler.java:92)
 E/AndroidRuntime(2648):    at android.os.Looper.loop(Looper.java:137)
 E/AndroidRuntime(2648):    at android.app.ActivityThread.main(ActivityThread.java:5041)
 E/AndroidRuntime(2648):    at java.lang.reflect.Method.invokeNative(Native Method)
 E/AndroidRuntime(2648):    at java.lang.reflect.Method.invoke(Method.java:511)
 E/AndroidRuntime(2648):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
 E/AndroidRuntime(2648):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
 E/AndroidRuntime(2648):    at dalvik.system.NativeStart.main(Native Method)
 E/Trace(2698): error opening trace file: No such file or directory (2)

Answer 1

Use setOnCheckedChangeListener for CheckBox c instead setOnClickListener.

@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {

    int id = buttonView.getId();

    if(id == R.id.chk_register_type){
              // ....
    }

By this way you will be sure that you load CheckBox with proper id

Answer 2

 checkRegistrationTypes = (CheckBox) v.findViewById(R.id.chk_register_type)
                            .findViewWithTag("RegistrationType " + i + " " + regTypes.length);

you are looking your checkbox in the wrong place. it belongs to the View hiearchy of your activity no to the view you pressed. Also you should check against NPE.

Use

checkRegistrationTypes = (CheckBox)  findViewById(R.id.chk_register_type)
                            .findViewWithTag("RegistrationType " + i + " " + regTypes.length);