onClick Sign Up method includes onClick Datepicker, how to make it work?

Using Firebase to save User's information by Registering/SignUp. Then I met an obstacle....

I'm using switch case for onClick, which one is for registerpage() method which in form of Button & another for going to next activity via textview. But at the registerpage() method, there is a onClick DatePicker (for selecting dateOfBirth) . But the onClick for DatePicker doesn't work. Here's my code. Thank you.

registerPage.java

package com.example.sportsbuddyz;
import android.app.DatePickerDialog;
import android.app.ProgressDialog;
import android.content.Intent;
import android.graphics.Color;
import android.graphics.drawable.ColorDrawable;
import android.media.tv.TvContract;
import android.nfc.Tag;
import android.support.annotation.NonNull;
import android.support.v7.app.ActionBar;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.util.Patterns;
import android.view.View;
import android.widget.Button;
import android.widget.DatePicker;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.OnFailureListener;
import com.google.android.gms.tasks.Task;
import com.google.firebase.auth.AuthResult;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import java.util.Calendar;
import java.util.Date;
import java.util.HashMap;
public class registerPage extends AppCompatActivity implements View.OnClickListener {
EditText jEmailEt, jPasswordEt;
Button jSignUpBtn;
ProgressDialog progressDialog;
private FirebaseAuth mAuth;
TextView jAccountExist;
EditText jName, jStudentID, jPhoneNumber, jAddress;
TextView jDOB, jAutoAge;
DatePickerDialog.OnDateSetListener mDateSetListener;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.registerpage);
jEmailEt = findViewById(R.id.emailEt);
jPasswordEt = findViewById(R.id.passwordEt);
//jSignUpBtn = findViewById(R.id.signupBtn);
mAuth = FirebaseAuth.getInstance();
//jAccountExist = findViewById(R.id.accountExist);
jName = findViewById(R.id.nameEt);
jStudentID = findViewById(R.id.studentIDEt);
jPhoneNumber = findViewById(R.id.phoneEt);
jAddress = findViewById(R.id.addressEt);
jDOB = findViewById(R.id.DOB);
jAutoAge = findViewById(R.id.AgeAuto);
ActionBar actionBar = getSupportActionBar();
actionBar.setTitle("Sign Up Account");
actionBar.setDisplayHomeAsUpEnabled(true);
actionBar.setDisplayShowHomeEnabled(true);
progressDialog = new ProgressDialog(this);
progressDialog.setMessage("Progressing User...");
findViewById(R.id.signupBtn).setOnClickListener(this);
findViewById(R.id.accountExist).setOnClickListener(this);
findViewById(R.id.DOB).setOnClickListener(this);
}
@Override
public void onClick(View view){
switch (view.getId()){
//CASE 1 -- SignUp Button
case R.id.signupBtn:{
registerUser();
}
break;
//CASE 2 -- AccountExist(Text)
case R.id.accountExist: {
startActivity(new Intent(registerPage.this, loginPage.class));
finish();
}
break;
}
}
private void registerUser(){
progressDialog.show();
String email = jEmailEt.getText().toString().trim();
String password = jPasswordEt.getText().toString().trim();
String name = jName.getText().toString().trim();
String studentID = jStudentID.getText().toString().trim();
String phoneNo = jPhoneNumber.getText().toString().trim();
String address = jAddress.getText().toString().trim();
if (email.isEmpty()) {
jEmailEt.setError("Email must not be empty");
jEmailEt.setFocusable(true);
return;
}
if (!Patterns.EMAIL_ADDRESS.matcher(email).matches()) {
jEmailEt.setError("Invalid Email");
jEmailEt.setFocusable(true);
return;
}
if (password.isEmpty()) {
jPasswordEt.setError("Password must not be empty");
jPasswordEt.setFocusable(true);
return;
}
if (password.length() < 6) {
jPasswordEt.setError("Password must be at least 6 digit");
jPasswordEt.setFocusable(true);
return;
}
if (name.isEmpty()) {
jName.setError("Name must not be empty");
jName.setFocusable(true);
return;
}
if (studentID.isEmpty()) {
jStudentID.setError("Student ID must not be empty");
jStudentID.setFocusable(true);
return;
}
if (phoneNo.isEmpty()) {
jPhoneNumber.setError("Phone Number must not be empty");
jPhoneNumber.setFocusable(true);
return;
}
if (address.isEmpty()) {
jAddress.setError("Address must not be empty");
jAddress.setFocusable(true);
return;
}
jDOB.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Calendar calendar = Calendar.getInstance();
int year = calendar.get(Calendar.YEAR);
int month = calendar.get(Calendar.MONTH);
int day = calendar.get(Calendar.DAY_OF_MONTH);
DatePickerDialog datePickerDialog = new DatePickerDialog(registerPage.this, android.R.style.Theme_Holo_Dialog_MinWidth, mDateSetListener, year, month, day);
datePickerDialog.getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
datePickerDialog.show();
}
});
mDateSetListener = new DatePickerDialog.OnDateSetListener() {
@Override
public void onDateSet(DatePicker view, int year, int month, int day) {
month = month + 1;
String dobDate = day + "/" + month + "/" + year;
jDOB.setText(dobDate);
jAutoAge.setText(getAge(year, month, day));
}
};
mAuth.createUserWithEmailAndPassword(email, password)
.addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
@Override
public void onComplete(@NonNull Task<AuthResult> task) {
if (task.isSuccessful()) {
// Sign in success, dismiss dialog & start register activity
progressDialog.dismiss();
//User userDetail = new User(email, name, studentID, phoneNo, address);
FirebaseUser user = mAuth.getCurrentUser();
//Get User email and UID from auth
String email = user.getEmail();
String uid = user.getUid();
String name = jName.getText().toString().trim();
String studentID = jStudentID.getText().toString().trim();
String phoneNo = jPhoneNumber.getText().toString().trim();
String address = jAddress.getText().toString().trim();
String DOB = jDOB.getText().toString().trim();
String Age = jAutoAge.getText().toString().trim();
//User is registered store user info in Firebase realtime database also
HashMap<Object,String> hashMap = new HashMap<>();
//Put Info in HashMap
hashMap.put("email",email);
hashMap.put("uid",uid);
hashMap.put("name", name);
hashMap.put("studentID", studentID);
hashMap.put("phone",phoneNo);
hashMap.put("address",address);
hashMap.put("Date Of Birth", DOB);
hashMap.put("Age",Age);
hashMap.put("image","");
hashMap.put("cover","");
//Firebase database instance
FirebaseDatabase database = FirebaseDatabase.getInstance();
//path to store user data named "Users"
DatabaseReference reference = database.getReference("Users");
//Put data within HashMap in database
reference.child(uid).setValue(hashMap);
Toast.makeText(registerPage.this, "Registered..\n"+user.getEmail(), Toast.LENGTH_SHORT).show();
startActivity(new Intent(registerPage.this, dashBoard.class));
finish();
} else {
// If sign in fails, display a message to the user.
progressDialog.dismiss();
Toast.makeText(registerPage.this, "Authentication failed.",
Toast.LENGTH_SHORT).show();
}
}
}).addOnFailureListener(new OnFailureListener() {
@Override
public void onFailure(@NonNull Exception e) {
progressDialog.dismiss();
Toast.makeText(registerPage.this, ""+e.getMessage(), Toast.LENGTH_SHORT).show();
}
});
}
private String getAge(int year, int month, int day){
Calendar dob = Calendar.getInstance();
Calendar today = Calendar.getInstance();
dob.set(year, month, day);
int age = today.get(Calendar.YEAR) - dob.get(Calendar.YEAR);
if (today.get(Calendar.DAY_OF_YEAR) < dob.get(Calendar.DAY_OF_YEAR)){
age--;
}
Integer ageInt = new Integer(age);
String ageS = ageInt.toString();
return ageS;
}
@Override
public boolean onSupportNavigateUp(){
onBackPressed();
return super.onSupportNavigateUp();
}
@Override
public void onPointerCaptureChanged(boolean hasCapture) {
}
}

registerpage.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".registerPage">
<ScrollView
android:layout_width="match_parent"
android:layout_height="wrap_content">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<!--Confirm Sign Up Button-->
<Button
android:id="@+id/signupBtn"
style="@style/Widget.AppCompat.Button.Small"
android:layout_width="163dp"
android:layout_height="47dp"
android:layout_centerHorizontal="true"
android:background="@drawable/loginbutton"
android:text="Sign Up"
android:layout_below="@id/accountExist"
android:layout_margin="10dp"
android:textAllCaps="false"
android:textStyle="bold" />
<!--EmailAddress-->
<android.support.design.widget.TextInputLayout
android:id="@+id/emailTIL"
android:layout_width="325dp"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_marginTop="120dp">
<EditText
android:id="@+id/emailEt"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Email Address"
android:inputType="textEmailAddress" />
</android.support.design.widget.TextInputLayout>
<!--Password-->
<android.support.design.widget.TextInputLayout
android:id="@+id/passwordTIL"
android:layout_width="325dp"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true"
android:layout_below="@+id/emailTIL"
app:passwordToggleEnabled="true">
<EditText
android:id="@+id/passwordEt"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Password"
android:inputType="textPassword" />
</android.support.design.widget.TextInputLayout>
<!--Name-->
<android.support.design.widget.TextInputLayout
android:id="@+id/nameTIL"
android:layout_width="325dp"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true"
android:layout_below="@+id/passwordTIL"
app:passwordToggleEnabled="true">
<EditText
android:id="@+id/nameEt"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Full Name"
android:inputType="textPersonName" />
</android.support.design.widget.TextInputLayout>
<!--Student ID-->
<android.support.design.widget.TextInputLayout
android:id="@+id/studentIDTIL"
android:layout_width="325dp"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true"
android:layout_below="@+id/nameTIL"
app:passwordToggleEnabled="true">
<EditText
android:id="@+id/studentIDEt"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Student ID" />
</android.support.design.widget.TextInputLayout>
<!--Phone Number-->
<android.support.design.widget.TextInputLayout
android:id="@+id/phoneTIL"
android:layout_width="325dp"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true"
android:layout_below="@+id/studentIDTIL"
app:passwordToggleEnabled="true">
<EditText
android:id="@+id/phoneEt"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Phone No."
android:inputType="phone" />
</android.support.design.widget.TextInputLayout>
<!--DOB-->
<TextView
android:id="@+id/DOB"
android:layout_width="150dp"
android:layout_height="50dp"
android:layout_marginBottom="140dp"
android:textAlignment="center"
android:hint="Date of Birth"
android:layout_below="@+id/addressTIL"
android:layout_marginTop="10dp"
android:layout_marginLeft="30dp"
android:textSize="20dp"/>
<!--Age-->
<TextView
android:id="@+id/AgeAuto"
android:layout_width="150dp"
android:layout_height="50dp"
android:layout_marginBottom="140dp"
android:textAlignment="center"
android:hint="Age"
android:layout_toRightOf="@+id/DOB"
android:layout_below="@id/addressTIL"
android:layout_margin="10dp"
android:layout_marginLeft="10dp"
android:textSize="20dp"/>
<!--Address-->
<android.support.design.widget.TextInputLayout
android:id="@+id/addressTIL"
android:layout_width="325dp"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true"
android:layout_below="@+id/phoneTIL"
app:passwordToggleEnabled="true">
<EditText
android:id="@+id/addressEt"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Address"
android:inputType="textShortMessage"/>
</android.support.design.widget.TextInputLayout>
<!--Already Register? Login now-->
<TextView
android:id="@+id/accountExist"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="140dp"
android:textAlignment="center"
android:text="Already have account? Login now"
android:layout_below="@+id/AgeAuto"
android:layout_margin="10dp"/>
</RelativeLayout>
</ScrollView>
</RelativeLayout>

You registered the click listener twice

onClick in xml and setOnClickListener in java code

So you have to remove one of them .. in your case remove onClickListener and put your code in switch case

@Override
public void onClick(View view){
switch (view.getId()){
case R.id.DOB:
Calendar calendar = Calendar.getInstance();
int year = calendar.get(Calendar.YEAR);
int month = calendar.get(Calendar.MONTH);
int day = calendar.get(Calendar.DAY_OF_MONTH);
DatePickerDialog datePickerDialog = new DatePickerDialog(registerPage.this, android.R.style.Theme_Holo_Dialog_MinWidth, mDateSetListener, year, month, day);
datePickerDialog.getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
datePickerDialog.show();
break;
}
}