feat(首页欢迎图, 加入第一次访问判断.):

lib/utils/shared_preferences.dart

@@ -1,13 +1,13 @@
 
 import 'dart:async';
 import 'package:shared_preferences/shared_preferences.dart';
-
+export 'package:flutter_go/resources/shared_preferences_keys.dart';
 ///
 /// 用来做shared_preferences的存储
 class SpUtil {
   static SpUtil _instance;
   static Future<SpUtil> get instance async {
-    return await _getInstance();
+    return await getInstance();
   }
 
   static SharedPreferences _spf;
@@ -19,7 +19,8 @@ class SpUtil {
     _spf = await SharedPreferences.getInstance();
   }
 
-  static Future<SpUtil> _getInstance() async  {
+  static Future<SpUtil> getInstance() async  {
+    print("_instance>>$_instance");
     if (_instance == null) {
       _instance = new SpUtil._();
       await _instance._init();
@@ -29,83 +30,90 @@ class SpUtil {
   }
 
   static bool _beforCheck() {
-    String a;
     if (_spf == null) {
-      return throw new StateError("SharedPreferences must be initialized first, but the insurance is null;");
+      return true;
     }
+    return false;
+  }
+  // 判断是否存在数据
+  bool hasKey(String key) {
+    Set keys = getKeys();
+    return keys.contains(key);
   }
 
-  static Set<String> getKeys() {
+  Set<String> getKeys() {
     if (_beforCheck()) return null;
     return _spf.getKeys();
   }
-  dynamic get(String key) {
+
+  get(String key) {
     if (_beforCheck()) return null;
-    return _spf.getKeys();
+    return _spf.get(key);
   }
-  static String getString(String key) {
+
+  getString(String key) {
     if (_beforCheck()) return null;
     return _spf.getString(key);
   }
 
-  static Future<bool> putString(String key, String value) {
+  Future<bool> putString(String key, String value) {
     if (_beforCheck()) return null;
     return _spf.setString(key, value);
   }
 
-  static bool getBool(String key) {
+  bool getBool(String key) {
     if (_beforCheck()) return null;
     return _spf.getBool(key);
   }
 
-  static Future<bool> putBool(String key, bool value) {
+  Future<bool> putBool(String key, bool value) {
     if (_beforCheck()) return null;
     return _spf.setBool(key, value);
   }
 
-  static int getInt(String key) {
+  int getInt(String key) {
     if (_beforCheck()) return null;
     return _spf.getInt(key);
   }
 
-  static Future<bool> putInt(String key, int value) {
+  Future<bool> putInt(String key, int value) {
     if (_beforCheck()) return null;
     return _spf.setInt(key, value);
   }
 
-  static double getDouble(String key) {
+  double getDouble(String key) {
     if (_beforCheck()) return null;
     return _spf.getDouble(key);
   }
 
-  static Future<bool> putDouble(String key, double value) {
+  Future<bool> putDouble(String key, double value) {
     if (_beforCheck()) return null;
     return _spf.setDouble(key, value);
   }
 
-  static List<String> getStringList(String key) {
+  List<String> getStringList(String key) {
     return _spf.getStringList(key);
   }
 
-  static Future<bool> putStringList(String key, List<String> value) {
+  Future<bool> putStringList(String key, List<String> value) {
     if (_beforCheck()) return null;
     return _spf.setStringList(key, value);
   }
 
-  static dynamic getDynamic(String key) {
+  dynamic getDynamic(String key) {
     if (_beforCheck()) return null;
     return _spf.get(key);
   }
 
 
 
-  static Future<bool> remove(String key) {
+  Future<bool> remove(String key) {
     if (_beforCheck()) return null;
     return _spf.remove(key);
   }
 
-  static Future<bool> clear() {
+  Future<bool> clear() {
     if (_beforCheck()) return null;
     return _spf.clear();
   }
-}
+}