i want way to disable the Home Button & Back Button when click on checkbox in application ,

my application on version 4.2.2

i have code but not work when click on checkbox work stop to application

public void HardButtonOnClick(View v)
    {
            boolean checked1 = ((CheckBox) v).isChecked();
            if(checked1)
            {   
                SQLiteDatabase db;                      
                db = openOrCreateDatabase("Saftey.db", SQLiteDatabase.CREATE_IF_NECESSARY, null);
                db.setVersion(1);
                db.setLocale(Locale.getDefault());
                db.setLockingEnabled(true);
                ContentValues values = new ContentValues();
                values.put("hardBtn", "YES");
                db.update("Setting", values, "id = ?", new String[] { "1" });
                Toast.makeText(this, "Hard Button Locked", Toast.LENGTH_LONG).show();
                //SharedPreferences pref = getSharedPreferences("pref",0);
                //SharedPreferences.Editor edit = pref.edit();
                //edit.putString("hard","yes");
                //edit.commit();
                /* String Lock="yes" ;
                 Bundle bundle = new Bundle();
                 bundle.putString("key", Lock);
                 Intent a = new Intent(Change_setting.this, ChildMode.class);
                 a.putExtras(bundle);
                 startActivity(a);*/
                super.onAttachedToWindow();
                this.getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD);
                isLock = true;
            }
            else
            {
                SQLiteDatabase db;                      
                db = openOrCreateDatabase("Saftey.db", SQLiteDatabase.CREATE_IF_NECESSARY, null);
                db.setVersion(1);
                db.setLocale(Locale.getDefault());
                db.setLockingEnabled(true);
                ContentValues values = new ContentValues();
                values.put("hardBtn", "NO");
                db.update("Setting", values, "id = ?", new String[] { "1" });
                //SharedPreferences pref = getSharedPreferences("pref",0);
                //SharedPreferences.Editor edit = pref.edit();
                //edit.putString("hard","no");
                //edit.commit();
                Toast.makeText(this, "Hard Button Un-Locked", Toast.LENGTH_LONG).show();
                isLock = false;
            }
    }

how can work it??