Android global variable

Question

How can I create global variable keep remain values around the life cycle of the application regardless which activity running

User · Answer

Easy      Those variable you wanna access as global variable  you can declare them as static variables  And now  you can access those variables by using  classname variablename   public class MyProperties   private static MyProperties mInstance  null   static int someValueIWantToKeep   protected MyProperties      public static synchronized MyProperties getInstance        if null    mInstance           mInstance   new MyProperties              return mInstance         MyProperites someValueIWantToKeep   Thats It

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There are a few different ways you can achieve what you are asking for   1   Extend the application class and instantiate your controller and model objects there   public class FavoriteColorsApplication extends Application        private static FavoriteColorsApplication application      private FavoriteColorsService service       public FavoriteColorsApplication getInstance             return application              Override     public void onCreate             super onCreate            application   this          application initialize               private void initialize             service   new FavoriteColorsService               public FavoriteColorsService getService             return service             Then you can call the your singleton from your custom Application object at any time   public class FavoriteColorsActivity extends Activity    private FavoriteColorsService service   null  private ArrayAdapter lt String gt  adapter  private List lt String gt  favoriteColors   new ArrayList lt String gt       Override protected void onCreate Bundle savedInstanceState        super onCreate savedInstanceState       setContentView R layout activity favorite colors        service     FavoriteColorsApplication  getApplication    getService        favoriteColors   service findAllColors         ListView lv    ListView  findViewById R id favoriteColorsListView       adapter   new ArrayAdapter lt String gt  this  R layout favorite colors list item              favoriteColors       lv setAdapter adapter       2   You can have your controller just create a singleton instance of itself   public class Controller       private static final String TAG    Controller       private static sController sController      private Dao mDao       private Controller             mDao   new Dao                   public static Controller create             if  sController    null                sController   new Controller                      return sController            Then you can just call the create method from any Activity or Fragment and it will create a new controller if one doesn t already exist  otherwise it will return the preexisting controller   3   Finally  there is a slick framework created at Square which provides you dependency injection within Android  It is called Dagger  I won t go into how to use it here  but it is very slick if you need that sort of thing   I hope I gave enough detail in regards to how you can do what you are hoping for

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import android app Application   public class Globals extends Application       private static Globals instance   null      private static int RecentCompaignID      private static int EmailClick      private static String LoginPassword      static String loginMemberID      private static String CompaignName           private static int listget 0        MailingDetails     private static String FromEmailadd         private static String FromName         private static String ReplyEmailAdd         private static String CompaignSubject         private static int TempId 0      private static int ListIds 0       private static String HTMLContent          Override     public void onCreate                  super onCreate            instance   this             public static Globals getInstance                 return instance             public void setRecentCompaignID int objRecentCompaignID                RecentCompaignID   objRecentCompaignID             public int getRecentCompaignID                  return RecentCompaignID             public void setLoginMemberID String objloginMemberID                 loginMemberID   objloginMemberID             public String getLoginMemberID                  return loginMemberID             public void setLoginMemberPassword String objLoginPassword                LoginPassword   objLoginPassword             public String getLoginMemberPassword                 return LoginPassword             public void setEmailclick int id                EmailClick   id             public int getEmailClick                  return EmailClick            public void setCompaignName String objCompaignName                CompaignName objCompaignName            public String getCompaignName                 return CompaignName            public void setlistgetvalue int objlistget                listget objlistget            public int getlistvalue                 return listget            public void setCompaignSubject String objCompaignSubject                 CompaignSubject objCompaignSubject            public String getCompaignSubject                 return CompaignSubject            public void setHTMLContent String objHTMLContent                HTMLContent objHTMLContent            public String getHTMLContent                 return HTMLContent            public void setListIds int objListIds                ListIds objListIds            public int getListIds                 return ListIds            public void setReplyEmailAdd String objReplyEmailAdd                ReplyEmailAdd objReplyEmailAdd            public String getReplyEmailAdd                 return ReplyEmailAdd            public void setFromName String objFromName                FromName objFromName            public String getFromName                 return FromName            public void setFromEmailadd String objFromEmailadd                FromEmailadd objFromEmailadd            public String getFromEmailadd                 return FromEmailadd

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Try Like This   Create a shared data class   SharedData java  import android app Application          Created by kundan on 6 23 2015      public class Globals         private static Globals instance   new Globals            Getter-Setters     public static Globals getInstance             return instance             public static void setInstance Globals instance            Globals instance   instance             private String notification index        private Globals                  public String getValue             return notification index              public void setValue String notification index            this notification index   notification index               Declared Initiaze an instance of class globally in those classes where you want to set get data  using this code before onCreate   method  -  Globals sharedData   Globals getInstance      Set data   sharedData setValue  kundan      Get data   String n   sharedData getValue

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My Class Global Variables  Save File Global Java public class Global       public static int myVi       public static String myVs        How to used on many Activity  Global myVi   12  Global myVs    my number                              int i  int s  i   Global myVi  s   Global myVs     is     Global myVi

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This global variable works for my project    public class Global       public static int ivar1  ivar2      public static String svar1  svar2      public static int   myarray1   new int 10           How to use other or many activity Global ivar1   10   int i   Global ivar1

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Technically this does not answer the question  but I would recommend using the Room database instead of any global variable   https   developer android com topic libraries architecture room html Even if you are  only  needing to store a global variable and it s no big deal and what not  but using the Room database is the most elegant  native and well supported way of keeping values around the life cycle of the activity   It will help to prevent many issues  especially integrity of data   I understand that database and global variable are different but please use Room for the sake of code maintenance  app stability and data integrity

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I checked for similar answer  but those given here don t fit my needs  I find something that  from my point of view  is what you re looking for  The only possible black point is a security matter  or maybe not  since I don t know about security   I suggest using Interface  no need to use Class with constructor and so      since you only have to create something like    public interface ActivityClass        public static final String MYSTRING 1    STRING        public static final int MYINT 1   1       Then you can access everywhere within your classes by using the following   int myInt   ActivityClass MYINT 1  String myString   ActivityClass MYSTRING 1

User · Answer

You can use a Singleton Pattern like this   package com ramps   public class MyProperties   private static MyProperties mInstance  null   public int someValueIWantToKeep   protected MyProperties      public static synchronized MyProperties getInstance             if null    mInstance               mInstance   new MyProperties                      return mInstance            In your application you can access your singleton in this way   MyProperties getInstance   someValueIWantToKeep

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You can extend the base android app Application class and add member variables like so   public class MyApplication extends Application        private String someVariable       public String getSomeVariable             return someVariable             public void setSomeVariable String someVariable            this someVariable   someVariable            In your android manifest you must declare the class implementing android app Application  add the android name   MyApplication  attribute to the existing application tag     lt application    android name   MyApplication     android icon   drawable icon     android label   string app name  gt    Then in your activities you can get and set the variable like so      set   MyApplication  this getApplication    setSomeVariable  foo        get String s     MyApplication  this getApplication    getSomeVariable

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You could use application preferences  They are accessible from any activity or piece of code as long as you pass on the Context object  and they are private to the application that uses them  so you don t need to worry about exposing application specific values  unless you deal with routed devices  Even so  you could use hashing or encryption schemes to save the values  Also  these preferences are stored from an application run to the next  Here is some code examples that you can look at

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You can create a Global Class like this   public class GlobalClass extends Application       private String name      private String email       public String getName             return name             public void setName String aName            name   aName             public String getEmail             return email             public void setEmail String aEmail            email   aEmail            Then define it in the manifest     lt application     android name  com example globalvariable GlobalClass         Now you can set values to global variable like this   final GlobalClass globalVariable    GlobalClass  getApplicationContext    globalVariable setName  Android Example context variable      You can get those values like this   final GlobalClass globalVariable    GlobalClass  getApplicationContext    final String name    globalVariable getName      Please find complete example from this blog Global Variables

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Use SharedPreferences to store and retrieve global variables   SharedPreferences preferences   PreferenceManager getDefaultSharedPreferences this   String userid   preferences getString  userid   null

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If possible  you should declare the variables that you need to keep alive that haven t been clear by Garbage Collector or Unload by OS in file  so To do it  you must code by C C   and compile to  so lib file and load it in your MainActivity

[android] Android global variable

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