Why my method is not able to check if my user is exist or not before they are able to create a new account?

Question

I added the method to check the existence of the user's email in the database. For instance, an existing user cannot use the same email to register account again. But I am still able to register my account with the same email. There is no error in my code. I don't know where is the problem. Can you all help me with this problem?

This is the method I add in my DatabaseHelper.JAVA

public boolean userExists (String email){
    String [] columns = {C_EMAIL};
    SQLiteDatabase db = getReadableDatabase();
    String selection = C_EMAIL + "=?";
    String selectionArgs []= { email };
    Cursor cursor = db.query(TABLE_NAME,columns,selection,selectionArgs,null,null,null);
    return true;
}

This is my MainActivity.Java

private void getData() {
    email = "" + Pemail.getText().toString().trim();
    name = "" + Pname.getText().toString().trim();
    age = "" + PAge.getText().toString().trim();
    phone = "" + Pphone.getText().toString().trim();
    preferenceselected = "" + Ppreferenceselected.getText().toString().trim();
    password = "" + Ppassword.getText().toString().trim();


    if (email.isEmpty() || name.isEmpty() || age.isEmpty() || phone.isEmpty() || preferenceselected.isEmpty() || password.isEmpty()) {
        Toast.makeText(this, "Please fill all the information", Toast.LENGTH_SHORT).show();
        if (dbHelper.userExists(email)){
            Toast.makeText(this, "User Exist", Toast.LENGTH_SHORT).show();
            return;
        }
    }

    String timeStamp = "" + System.currentTimeMillis();

    boolean id = dbHelper.insertInfo(
            "" + imageUri,
            "" + email,
            "" + name,
            "" + age,
            "" + phone,
            "" + preferenceselected,
            "" + password,
            ""+timeStamp,
            ""+timeStamp

    );


    Toast.makeText(this, "Account Created", Toast.LENGTH_SHORT).show();
    Intent intent = new Intent(MainActivity.this, setting.class);
    startActivity(intent);


}

Answer 1

You must check if the user exists after the 1st if statement:

    if (email.isEmpty() || name.isEmpty() || age.isEmpty() || phone.isEmpty() || preferenceselected.isEmpty() || password.isEmpty()) {
        Toast.makeText(this, "Please fill all the information", Toast.LENGTH_SHORT).show();
        return;
    }
    if (dbHelper.userExists(email)){
        Toast.makeText(this, "User Exist", Toast.LENGTH_SHORT).show();
        return;
   }