v1.0.1 warning fixes

lib/util/common.dart

@@ -2,6 +2,7 @@ import 'dart:convert';
 import 'package:workouttest_util/util/app_language.dart';
 
 import 'package:flutter/material.dart';
+// ignore: depend_on_referenced_packages
 import 'package:intl/intl.dart';
 
 class DateRate {
@@ -11,7 +12,7 @@ class DateRate {
   static String yearly = "yearly";
 }
 
-mixin Common {
+mixin Common{
   final emailError = "Please type a right email address here.";
   final passwordError = "The password must have at least 8 characters.";
 
@@ -29,7 +30,7 @@ mixin Common {
 
     String dateName = DateFormat(DateFormat.YEAR_NUM_MONTH_DAY, AppLanguage().appLocal.toString()).format(date.toUtc());
     if (timeDisplay) {
-      dateName += " " + DateFormat(DateFormat.HOUR_MINUTE, AppLanguage().appLocal.toString()).format(date.toUtc());
+      dateName += " ${DateFormat(DateFormat.HOUR_MINUTE, AppLanguage().appLocal.toString()).format(date.toUtc())}";
     }
 
     return dateName;
@@ -51,7 +52,7 @@ mixin Common {
   }
 
   static String? emailValidation(String? email) {
-    final String error = "Please type an email address";
+    const String error = "Please type an email address";
     if (email == null) {
       return error;
     }
@@ -60,8 +61,8 @@ mixin Common {
   }
 
   static String? passwordValidation(String? value) {
-    final String error = "Password too short";
-    if (value == null || value.length == 0) {
+    const String error = "Password too short";
+    if (value == null || value.isEmpty) {
       return error;
     }
     bool valid = 8 < value.length;