Activity has leaked window - Custom Dialog

Question

I am trying to show a custom dialog within Activity and this error occur. I know why this error occur from here and here and also know it's solution. But the problem is I can't find the problem in my code. I've spent anlot of time in finding the error with no luck. I've called below method on button click

public void changePassword(View view){
    DialogChangePassword dialogChangePassword = new DialogChangePassword(ActivityMyAccount.this);
    dialogChangePassword.show();
    Window window = dialogChangePassword.getWindow();
    window.setLayout(WindowManager.LayoutParams.MATCH_PARENT, WindowManager.LayoutParams.WRAP_CONTENT);
    window.setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
}

I am showing the dialog here while Activity should live. My question;

1. I can't dismiss the dialog here, I am dismissing it from within Dialog class.
2. I am not finishing the activity. If error occurs because the activity is finishing, why is it finishing?
3. If error is not because of finishing the activity then why does this error occur?
4. I have a NetworkOperation to be performed in Dialog class, does it have to do something with that?

Here is my Dialog class

public class DialogChangePassword extends Dialog {
    Context context;
    Button confirm, cancel;

    CustomEditText edtOldPwd, edtNewPwd, edtConfirmNewPwd;

    ProgressDialog progressDialog;

    String PASSWORD_INCORRECT_MESSAGE = "Old password is incorrect.";

    public DialogChangePassword(Context context) {
        super(context);
        this.context = context;
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        setContentView(R.layout.dialog_change_password);

        if(progressDialog != null)
            progressDialog = null;

        progressDialog = new ProgressDialog(context);
        progressDialog.setTitle("Please wait...");
        progressDialog.setMessage("Updating Password.");
        progressDialog.show();


        confirm = (Button) findViewById(R.id.btnChangePassword);
        cancel = (Button) findViewById(R.id.btnCancel);

        edtOldPwd = (CustomEditText) findViewById(R.id.edtOldPassword);
        edtNewPwd = (CustomEditText) findViewById(R.id.edtNewPassword);
        edtConfirmNewPwd = (CustomEditText) findViewById(R.id.edtConfirmNewPassword);

        edtConfirmNewPwd.addTextChangedListener(new TextWatcher() {
            @Override
            public void beforeTextChanged(CharSequence s, int start, int count, int after) {

            }

            @Override
            public void onTextChanged(CharSequence s, int start, int before, int count) {

            }

            @Override
            public void afterTextChanged(Editable s) {
                if (!edtNewPwd.getText().toString().equals(edtConfirmNewPwd.getText().toString()))
                    edtConfirmNewPwd.setError("Password doesn't match");
            }
        });

        confirm.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (!edtNewPwd.getText().toString().equals(edtConfirmNewPwd.getText().toString())) {
                    Toast.makeText(context, "Password doesn't match",         Toast.LENGTH_SHORT).show();
                    progressDialog.cancel();
                    return;
                }
                HashMap<String, String> params = new HashMap<>();
                params.put("email", Utility.classUser.getEmailId());
                params.put("password", edtOldPwd.getText().toString());
                params.put("newPassword", edtNewPwd.getText().toString());
                new NetworkOperation().execute(params);
            }
        });
        cancel.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                dismiss();
            }
        });
    }

    private class NetworkOperation extends AsyncTask<HashMap<String,String>, Void, String> {
        @Override
        protected String doInBackground(HashMap<String, String>... params) {
            try {
                ClassAPIRoutes routes = ClassAPIRoutes.initializeRoutes();
                return routes.editUserPassword(params[0]);
            } catch (final IOException e) {
                e.printStackTrace();
                getOwnerActivity().runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        Toast.makeText(context, e.toString(), Toast.LENGTH_SHORT).show();
                    }
                });
                return "error";
            }
        }

        @Override
        protected void onPostExecute(String s) {
            super.onPostExecute(s);
            progressDialog.cancel();
            dismiss();
            if(!s.equals("error")){
                JSONObject jsonObject;
                try {
                    jsonObject = new JSONObject(s);
                    if (jsonObject.get("success").toString().equals("true")) {
                        Toast.makeText(context, "Password successfully changed.", Toast.LENGTH_SHORT).show();
                        dismiss();
                    } else if (jsonObject.get("success").toString().equals("false")) {
                        if (jsonObject.get("message").toString().equals(PASSWORD_INCORRECT_MESSAGE)) {
                            Toast.makeText(context, PASSWORD_INCORRECT_MESSAGE, Toast.LENGTH_SHORT).show();
                            resetFields();
                        }
                    }
                } catch (JSONException e) {
                    e.printStackTrace();
                    Toast.makeText(getContext(), s, Toast.LENGTH_SHORT).show();
                }
            }

        }
    }

    private void resetFields(){
        edtOldPwd.setText("");
        edtNewPwd.setText("");
        edtConfirmNewPwd.setText("");
    }

}

Answer 1

I've removed showing progress dialog from onCreate(...) and put it in Async class inside OnPreExecute(...) and it's working fine