Search Results

Search found 46088 results on 1844 pages for 'class loader'.

Page 405/1844 | < Previous Page | 401 402 403 404 405 406 407 408 409 410 411 412  | Next Page >

  • Observer pattern used with decorator pattern

    - by icelated
    I want to make a program that does an order entry system for beverages. ( i will probably do description, cost) I want to use the Decorator pattern and the observer pattern. I made a UML drawing and saved it as a pic for easy viewing. This site wont let me upload as a word doc so i have to upload a pic - i hope its easily viewable.... I need to know if i am doing the UML / design patterns correctly before moving on to the coding part. Beverage is my abstract component class. Espresso, houseblend, darkroast are my concrete subject classes.. I also have a condiment decorator class milk,mocha,soy,whip. would be my observer? because they would be interested in data changes to cost? Now, would the espresso,houseblend etc, be my SUBJECT and the condiments be my observer? My theory is that Cost is a changes and that the condiments need to know the changes? So, subject = esspresso,houseblend,darkroast,etc.. // they hold cost() Observer = milk,mocha,soy,whip? // they hold cost() would be the concrete components and the milk,mocha,soy,whip? would be the decorator! So, following good software engineering practices "design to an interface and not implementation" or "identify things that change from those that dont" would i need a costbehavior interface? If you look at the UML you will see where i am going with this and see if i am implementing observer + Decorator pattern correctly? I think the decorator is correct. since, the pic is not very viewable i will detail the classes here: Beverage class(register observer, remove observer, notify observer, description) these classes are the concrete beverage classes espresso, houseblend,darkroast, decaf(cost,getdescription,setcost,costchanged) interface observer class(update) // cost? interface costbehavior class(cost) // since this changes? condiment decorator class( getdescription) concrete classes that are linked to the 2 interface s and decorator are: milk,mocha,soy,whip(cost,getdescription,update) these are my decorator/ wrapper classes. Thank you.. Is there a way to make this picture bigger?

    Read the article

  • No method found compiler warning

    - by Magic Bullet Dave
    I have create a class from a string, check it is valid and then check if it responds to a particular method. If it does then I call the method. It all works fine, except I get an annoying compiler warning: "warning: no '-setCurrentID:' method found". Am I doing something wrong here? Is there anyway to tell the compiler all is ok and stop it reporting a warning? The here is the code: // Create an instance of the class id viewController = [[NSClassFromString(class) alloc] init]; // Check the class supports the methods to set the row and section if ([viewController respondsToSelector:@selector(setCurrentID:)]) { [viewController setCurrentID:itemID]; } // Push the view controller onto the tab bar stack [self.navigationController pushViewController:viewController animated:YES]; [viewController release]; Cheers Dave

    Read the article

  • [java bean]hibernate Session breaks a java bean?

    - by blow
    Hi all, i have a simple JPanel bean in my projects, now i want to drag my panel bean class into my jframe. My panel bean class is like this: public class BeanPanel extends javax.swing.JPanel { /** Creates new form BeanPanel */ public BeanPanel () { initComponents(); Session session=HibernateUtil.getSessionFactory().openSession(); } This code seem to break the bean: Session session=HibernateUtil.getSessionFactory().openSession(); When i try to drag the class into my JFrame bean i had this error message: This component cannot be instantiated. Please make sure it is a JavaBeans Component If i comment it all works fine. What is the reason of this? Thanks.

    Read the article

  • how to deal a constructor with an array in Perl

    - by superstar
    whats the difference between these two 'new' constructors in perl? 1) sub new { my $class = shift; my $self = {}; $self->{firstName} = undef; $self->{lastName} = undef; $self->{PEERS} = []; bless ($self, $class); return $self; } 2) sub new { my $class = shift; my $self = { _firstName => shift, _lastName => shift, _ssn => shift, }; bless $self, $class; return $self; } I am using the 2nd one so far, but i need to implement the arrays in perl? can you suggest a way to do it with the 2nd 'new' constructor and how can we use get and set methods on those array variables?

    Read the article

  • Rails named_scope across multiple tables

    - by wakiki
    I'm trying to tidy up my code by using named_scopes in Rails 2.3.x but where I'm struggling with the has_many :through associations. I'm wondering if I'm putting the scopes in the wrong place... Here's some pseudo code below. The problem is that the :accepted named scope is replicated twice... I could of course call :accepted something different but these are the statuses on the table and it seems wrong to call them something different. Can anyone shed light on whether I'm doing the following correctly or not? I know Rails 3 is out but it's still in beta and it's a big project I'm doing so I can't use it in production yet. class Person < ActiveRecord::Base has_many :connections has_many :contacts, :through => :connections named_scope :accepted, :conditions => ["connections.status = ?", Connection::ACCEPTED] # the :accepted named_scope is duplicated named_scope :accepted, :conditions => ["memberships.status = ?", Membership::ACCEPTED] end class Group < ActiveRecord::Base has_many :memberships has_many :members, :through => :memberships end class Connection < ActiveRecord::Base belongs_to :person belongs_to :contact, :class_name => "Person", :foreign_key => "contact_id" end class Membership < ActiveRecord::Base belongs_to :person belongs_to :group end I'm trying to run something like person.contacts.accepted and group.members.accepted which are two different things. Shouldn't the named_scopes be in the Membership and Connection classes? One solution is to just call the two different named scope something different in the Person class or even to create separate associations (ie. has_many :accepted_members and has_many :accepted_contacts) but it seems hackish and in reality I have many more than just accepted (ie. banned members, ignored connections, pending, requested etc etc)

    Read the article

  • C++ type-checking at compile-time

    - by Masterofpsi
    Hi, all. I'm pretty new to C++, and I'm writing a small library (mostly for my own projects) in C++. In the process of designing a type hierarchy, I've run into the problem of defining the assignment operator. I've taken the basic approach that was eventually reached in this article, which is that for every class MyClass in a hierarchy derived from a class Base you define two assignment operators like so: class MyClass: public Base { public: MyClass& operator =(MyClass const& rhs); virtual MyClass& operator =(Base const& rhs); }; // automatically gets defined, so we make it call the virtual function below MyClass& MyClass::operator =(MyClass const& rhs); { return (*this = static_cast<Base const&>(rhs)); } MyClass& MyClass::operator =(Base const& rhs); { assert(typeid(rhs) == typeid(*this)); // assigning to different types is a logical error MyClass const& casted_rhs = dynamic_cast<MyClass const&>(rhs); try { // allocate new variables Base::operator =(rhs); } catch(...) { // delete the allocated variables throw; } // assign to member variables } The part I'm concerned with is the assertion for type equality. Since I'm writing a library, where assertions will presumably be compiled out of the final result, this has led me to go with a scheme that looks more like this: class MyClass: public Base { public: operator =(MyClass const& rhs); // etc virtual inline MyClass& operator =(Base const& rhs) { assert(typeid(rhs) == typeid(*this)); return this->set(static_cast<Base const&>(rhs)); } private: MyClass& set(Base const& rhs); // same basic thing }; But I've been wondering if I could check the types at compile-time. I looked into Boost.TypeTraits, and I came close by doing BOOST_MPL_ASSERT((boost::is_same<BOOST_TYPEOF(*this), BOOST_TYPEOF(rhs)>));, but since rhs is declared as a reference to the parent class and not the derived class, it choked. Now that I think about it, my reasoning seems silly -- I was hoping that since the function was inline, it would be able to check the actual parameters themselves, but of course the preprocessor always gets run before the compiler. But I was wondering if anyone knew of any other way I could enforce this kind of check at compile-time.

    Read the article

  • Does this inheritance design belong in the database?

    - by Berryl
    === CLARIFICATION ==== The 'answers' older than March are not answers to the question in this post! Hello In my domain I need to track allocations of time spent on Activities by resources. There are two general types of Activities of interest - ones base on a Project and ones based on an Account. The notion of Project and Account have other features totally unrelated to both each other and capturing allocations of time, and each is modeled as a table in the database. For a given Allocation of time however, it makes sense to not care whether the allocation was made to either a Project or an Account, so an ActivityBase class abstracts away the difference. An ActivityBase is either a ProjectActivity or an AccountingActivity (object model is below). Back to the database though, there is no direct value in having tables for ProjectActivity and AccountingActivity. BUT the Allocation table needs to store something in the column for it's ActivityBase. Should that something be the Id of the Project / Account or a reference to tables for ProjectActivity / Accounting? How would the mapping look? === Current Db Mapping (Fluent) ==== Below is how the mapping currently looks: public class ActivityBaseMap : IAutoMappingOverride<ActivityBase> { public void Override(AutoMapping<ActivityBase> mapping) { //mapping.IgnoreProperty(x => x.BusinessId); //mapping.IgnoreProperty(x => x.Description); //mapping.IgnoreProperty(x => x.TotalTime); mapping.IgnoreProperty(x => x.UniqueId); } } public class AccountingActivityMap : SubclassMap<AccountingActivity> { public void Override(AutoMapping<AccountingActivity> mapping) { mapping.References(x => x.Account); } } public class ProjectActivityMap : SubclassMap<ProjectActivity> { public void Override(AutoMapping<ProjectActivity> mapping) { mapping.References(x => x.Project); } } There are two odd smells here. Firstly, the inheritance chain adds nothing in the way of properties - it simply adapts Projects and Accounts into a common interface so that either can be used in an Allocation. Secondly, the properties in the ActivityBase interface are redundant to keep in the db, since that information is available in Projects and Accounts. Cheers, Berryl ==== Domain ===== public class Allocation : Entity { ... public virtual ActivityBase Activity { get; private set; } ... } public abstract class ActivityBase : Entity { public virtual string BusinessId { get; protected set; } public virtual string Description { get; protected set; } public virtual ICollection<Allocation> Allocations { get { return _allocations.Values; } } public virtual TimeQuantity TotalTime { get { return TimeQuantity.Hours(Allocations.Sum(x => x.TimeSpent.Amount)); } } } public class ProjectActivity : ActivityBase { public virtual Project Project { get; private set; } public ProjectActivity(Project project) { BusinessId = project.Code.ToString(); Description = project.Description; Project = project; } }

    Read the article

  • Retrieving accessors in IronRuby

    - by rsteckly
    I'm trying to figure out how to retrieve the value stored in the Person class. The problem is just that after I define an instance of the Person class, I don't know how to retrieve it within the IronRuby code because the instance name is in the .NET part. /*class Person attr_accessor :name def initialize(strname) self.name=strname end end*/ //We start the DLR, in this case starting the Ruby version ScriptEngine engine = IronRuby.Ruby.CreateEngine(); ScriptScope scope = engine.ExecuteFile("c:\\Users\\ron\\RubymineProjects\\untitled\\person.rb"); //We get the class type object person = engine.Runtime.Globals.GetVariable("Person"); //We create an instance object marcy = engine.Operations.CreateInstance(person, "marcy");

    Read the article

  • Create a Models Diagram Using Railroad

    - by SeeBees
    Railroad is a great UML tool for Ruby on Rails. It can automatically generate class diagrams of models and controllers. For models, a railroad-generated class diagram shows attributes of each model and the associations between one model and another. A sample diagram can be found here. It is very useful for a developer to see attributes and associations of models. While attributes and associations reveal the inner states and relationships of models, methods specify their behaviours. They are all desirable in a class diagram. I would like railroad to generate a class diagram that also lists methods for models, which will help me to know what each model does. I know methods are displayed in a diagram that is generated for controllers, but I don't see such an option for a diagram of models. Does someone know how to do that with railroad? Or is that possible? Thanks!

    Read the article

  • In C#, are event handler arguments covariant?

    - by Roger Lipscombe
    Maybe covariant's not the word, but if I have a class that raises an event, with (e.g.) FrobbingEventArgs, am I allowed to handle it with a method that takes EventArgs? Here's some code: class Program { static void Main(string[] args) { Frobber frobber = new Frobber(); frobber.Frobbing += FrobberOnFrobbing; frobber.Frob(); } private static void FrobberOnFrobbing(object sender, EventArgs e) { // Do something interesting. Note that the parameter is 'EventArgs'. } } internal class Frobber { public event EventHandler<FrobbingEventArgs> Frobbing; public event EventHandler<FrobbedEventArgs> Frobbed; public void Frob() { OnFrobbing(); // Frob. OnFrobbed(); } private void OnFrobbing() { var handler = Frobbing; if (handler != null) handler(this, new FrobbingEventArgs()); } private void OnFrobbed() { var handler = Frobbed; if (handler != null) handler(this, new FrobbedEventArgs()); } } internal class FrobbedEventArgs : EventArgs { } internal class FrobbingEventArgs : EventArgs { } The reason I ask is that ReSharper seems to have a problem with (what looks like) the equivalent in XAML, and I'm wondering if it's a bug in ReSharper, or a mistake in my understanding of C#.

    Read the article

  • Crazy interview question

    - by benjamin button
    I was asked this crazy question. I was out of my wits. Can a method in base class which is declared as virtual be called using the base class pointer which is pointing to a derived class object? Is this possible?

    Read the article

  • How to record / capture audio with RecordControl on Java ME, SE K770i

    - by tomaszs
    I want to record sound on my Java ME App on K770i. So I used this: http://java.sun.com/javame/reference/apis/jsr135/javax/microedition/media/control/RecordControl.html example of RecordControl in my code. It goes like this: import java.util.Vector; import javax.microedition.lcdui.Choice; import javax.microedition.lcdui.Command; import javax.microedition.lcdui.CommandListener; import javax.microedition.lcdui.Display; import javax.microedition.lcdui.Displayable; import javax.microedition.lcdui.List; import javax.microedition.media.Manager; import javax.microedition.media.MediaException; import javax.microedition.midlet.MIDlet; import java.io.*; import javax.microedition.lcdui.*; import javax.microedition.media.*; import javax.microedition.media.control.*; import javax.microedition.midlet.*; import javax.microedition.rms.*; (...) try { // Create a Player that captures live audio. Player p = Manager.createPlayer("capture://audio"); p.realize(); // Get the RecordControl, set the record stream, // start the Player and record for 5 seconds. RecordControl rc = (RecordControl)p.getControl("RecordControl"); ByteArrayOutputStream output = new ByteArrayOutputStream(); rc.setRecordStream(output); rc.startRecord(); p.start(); Thread.currentThread().sleep(5000); rc.commit(); p.close(); } catch (IOException ioe) { } catch (MediaException me) { } catch (InterruptedException ie) { } But unfortunately when I try to build it, it tells me: *** Creating directories *** *** Compiling source files *** ..\src\example\audiodemo\AudioPlayer.java:121: cannot find symbol symbol : class RecordControl location: class example.audiodemo.AudioPlayer RecordControl rc = (RecordControl)p.getControl("RecordControl"); ^ ..\src\example\audiodemo\AudioPlayer.java:121: cannot find symbol symbol : class RecordControl location: class example.audiodemo.AudioPlayer RecordControl rc = (RecordControl)p.getControl("RecordControl"); ^ 2 errors So my question is: why there is no RecordControl class if in documentations it is written this class should be there. Or is there other method to record / capture audio from microfone in Java ME of Sony Ericsson? How do you record sound?

    Read the article

  • FormEditor receiving NULL IEditorInput object

    - by Gabriel Parenza
    Hi, I have extended IEditorInput class to define my own IEditorInput object. Furthermore, I have extended FormEditor class. I have view where I am displaying my application objects. Whenever user double clicks on items on view, I intend to display more details for this application object on the editor, which is a FormEditor. Problem I am facing is that I am receiving IEditorInput object as NULL inside extended FormEditor class. Can someone please tell me what I am doing wrong? Code: CustomFormEditor extends FormEditor CustomEditorInput extends IEditorInput In View class: PlatformUI.getWorkbench().getActiveWorkbenchWindow().getActivePage().openEditor(new CustomEditorInput("test"),"editor.id"); Thanks, Gaurav.

    Read the article

  • How to make Date locale-independent? (GMT timezone newbie question)

    - by folone
    I have a db, that stores dates in OleDateTime format, in GMT timezone. I've implemented a class, extending Date in java to represent that in classic date format. But my class is locale-dependent (I'm in GMT+2). Therefore, it converts the date in the db as date - 2 hours. How do I make it convert the date correctly? I want my class to be locale-independent, always using GMT timezone. Actually, the question is: class MyOleDateTime extends Date { static { Locale.setDefault(WhatGoesHere?) } // ... some constructors // ... some methods }

    Read the article

  • Finding the closest object in proxmity to the mouse Coordinates

    - by Cam
    Hey there, i've been working on a problem for a while now, which involves targeting the closest movieClip in relation to the x y coords of the mouse, I've attached a nice little acompanying graphic. Each mc added to the stage has it's own sub-class (HotSpots) which uses Pythag to measure distance from mouse. At this stage i can determine the closest value from my Main class but can't figure out how to reference it back to the movieclip... hope this makes sense. Below are the two Classes. My Main Class which attachs the mcs, and monitors mouse movement and traces closest value package { import flash.display.*; import flash.text.*; import flash.events.*; public class Main extends MovieClip { var pos:Number = 50; var nodeArray:Array; public function Main(){ nodeArray = []; for(var i:int = 0; i < 4; i++) { var hotSpot_mc:HotSpots = new HotSpots; hotSpot_mc.x += pos; hotSpot_mc.y += pos; addChild(hotSpot_mc); nodeArray.push(hotSpot_mc); // set some pos pos += 70; } stage.addEventListener(MouseEvent.MOUSE_MOVE,updateProxmity) } public function updateProxmity(e:MouseEvent):void { var tempArray:Array = new Array(); for(var i:int = 0; i < 4; i++) { this['tf'+[i]].text = String(nodeArray[i].dist); tempArray.push(nodeArray[i].dist); } tempArray.sort(Array.NUMERIC); var minValue:int = tempArray[0]; trace(minValue) } } } My HotSpots Class package { import flash.display.MovieClip; import flash.events.Event; import flash.text.TextField; public class HotSpots extends MovieClip { public var XSide:Number; public var YSide:Number; public var dist:Number = 0; public function HotSpots() { addEventListener(Event.ENTER_FRAME, textUp); } public function textUp(event:Event):void { XSide = this.x - MovieClip(root).mouseX; YSide = this.y - MovieClip(root).mouseY; dist = Math.round((Math.sqrt(XSide*XSide + YSide*YSide))); } } } thanks in advance

    Read the article

  • Webpage data scraping using Java

    - by Gemma
    I am now trying to implement a simple HTML webpage scraper using Java.Now I have a small problem. Suppose I have the following HTML fragment. <div id="sr-h-left" class="sr-comp"> <a class="link-gray-underline" id="compare_header" rel="nofollow" href="javascript:i18nCompareProd('/serv/main/buyer/ProductCompare.jsp?nxtg=41980a1c051f-0942A6ADCF43B802');"> <span style="cursor: pointer;" class="sr-h-o">Compare</span> </a> </div> <div id="sr-h-right" class="sr-summary"> <div id="sr-num-results"> <div class="sr-h-o-r">Showing 1 - 30 of 1,439 matches, The data I am interested is the integer 1.439 shown at the bottom.I am just wondering how can I get that integer out of the HTML. I am now considering using a regular expression,and then use the java.util.Pattern to help get the data out,but still not very clear about the process. I would be grateful if you guys could give me some hint or idea on this data scraping. Thanks a lot.

    Read the article

  • "Inherited" types using CRTP and typedef

    - by Ken Moynihan
    The following code does not compile. I get an error message: error C2039: 'Asub' : is not a member of 'C' Can someone help me to understand this? Tried VS2008 & 2010 compiler. template <class T> class B { typedef int Asub; public: void DoSomething(typename T::Asub it) { } }; class C : public B<C> { public: typedef int Asub; }; class A { public: typedef int Asub; }; int _tmain(int argc, _TCHAR* argv[]) { C theThing; theThing.DoSomething(C::Asub()); return 0; }

    Read the article

  • One-to-many relationship with JDO in Google App Engine

    - by Marvin
    I've followed the GAE docs on setting up one-to-many relationship in JDO but I'm still having trouble in retrieving the collection data back. I have no problem getting the other non-collection fields back. Here are my classes: @PersistenceCapable public class User{ @PrimaryKey @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY) private Key key; @Persistent private String uniqueId; @Persistent private String email; @Persistent private List<Address> addresses = new ArrayList<Address>() ; ... } @PersistenceCapable public class Phone{ @PrimaryKey @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY) private Key key; @Persistent private String number; ... } public class UserDaoImpl implements UserDao { public void insertUser(User user) { if(user.getKey() == null) { com.google.appengine.api.datastore.Key key = KeyFactory.createKey(User.class.getSimpleName(), user.getEmail()); user.setKey(key); } PersistenceManager pm = PersistenceManagerWrapper.getPersistenceManager(); notNull(user); try { pm.makePersistent(user); } finally { pm.close(); } } @SuppressWarnings("unchecked") public User getUser(String uniqueId) { PersistenceManager pm = PersistenceManagerWrapper.getPersistenceManager(); Query query = pm.newQuery(User.class); query.setFilter("uniqueId == uniqueIdParam"); query.declareParameters("String uniqueIdParam"); User user = null; try { List<User> users = (List<User>)(query.execute(uniqueId)); //TODO abstract this if(users.size() > 0) user = users.get(0); } finally { pm.close(); } return user; } } public class UserDaoImplTest { @Test public void getUserTest() { User user = createTestUser(); assertNotNull("The user object should not be null", user); userDao.insertUser(user); User returnedUser = userDao.getUser(TEST_USER_ID); assertNotNull("The returnedUser object should not be null", returnedUser); Assert.assertPropertyEqualsExcludeProperties("User Object", user, returnedUser, ""); } } When I run the test, all the properties for User is populated but the list of Phone if I get is empty.

    Read the article

  • MEF GetExports<T, TMetaDataView> returning nothing with AllowMultiple = True

    - by sohum
    I don't understand MEF very well, so hopefully this is a simple fix of how I think it works. I'm trying to use MEF to get some information about a class and how it should be used. I'm using the Metadata options to try to achieve this. My interfaces and attribute looks like this: public interface IMyInterface { } public interface IMyInterfaceInfo { Type SomeProperty1 { get; } double SomeProperty2 { get; } string SomeProperty3 { get; } } [MetadataAttribute] [AttributeUsage(AttributeTargets.Class, AllowMultiple = true)] public class ExportMyInterfaceAttribute : ExportAttribute, IMyInterfaceInfo { public ExportMyInterfaceAttribute(Type someProperty1, double someProperty2, string someProperty3) : base(typeof(IMyInterface)) { SomeProperty1 = someProperty1; SomeProperty2 = someProperty2; SomeProperty3 = someProperty3; } public Type SomeProperty1 { get; set; } public double SomeProperty2 { get; set; } public string SomeProperty3 { get; set; } } The class that is decorated with the attribute looks like this: [ExportMyInterface(typeof(string), 0.1, "whoo data!")] [ExportMyInterface(typeof(int), 0.4, "asdfasdf!!")] public class DecoratedClass : IMyInterface { } The method that is trying to use the import looks like this: private void SomeFunction() { // CompositionContainer is an instance of CompositionContainer var myExports = CompositionContainer.GetExports<IMyInterface, IMyInterfaceInfo>(); } In my case myExports is always empty. In my CompositionContainer, I have a Part in my catalog that has two ExportDefinitions, both with the following ContractName: "MyNamespace.IMyInterface". The Metadata is also loaded correctly per my exports. If I remove the AllowMultiple setter and only include one exported attribute, the myExports variable now has the single export with its loaded metadata. What am I doing wrong?

    Read the article

  • Ask Basic Configurator in Apache Commong Log

    - by adisembiring
    I use log4j as logger for my web application. in log4j, I can set the level log in log4j properties or log4j.xml. in log4j, we instance logger as follows: static Logger logger = Logger.getLogger(SomeClass.class); I init log4j basic configurator in a servlet file using init method. But, I usually test application using JUnit, So I init the basic configurator in setup method. after that, I test the application, and I can see the log. Because I deployed, the web in websphere. I change all of logging instance become: private Log log = LogFactory.getLog(Foo.class); I don't know how to load basic configurator using ACL. so I can't control debug level to my JUnit test. do you have any suggestion, without changing static Logger logger = Logger.getLogger(SomeClass.class); become static Logger logger = Logger.getLogger(SomeClass.class);

    Read the article

  • Duplication of menu items with ViewPager and Fragments

    - by Julian
    I'm building an Android Application (minimum SDK Level 10, Gingerbread 2.3.3) with some Fragments in a ViewPager. I'm using ActionBarSherlock to create an ActionBar and android-viewpagertabs to add tabs to the ViewPager just like in the Market client. I have one global menu item that I want to be shown on every tab/fragment. On the first of the three tabs I want to have two additional menu items. But now two strange things happen: First if I start the app, everything seems to be fine, I can see all three menu items on the first page and only one item if i swipe to the second and third tab. But if I swipe back to the second tab from the third one, I can see all three items again which shouldn't happen. If I swipe back to the first and then again to the second tab, everything is fine again. The other strange thing is that every time I rotate the device, the menu items from the fragment are added again, even though they are already in the menu. Code of the FragmentActivity that displays the ViewPager and its tabs: public class MainActivity extends FragmentActivity { public static final String TAG = "MainActivity"; private ActionBar actionBar; private Adapter adapter; private ViewPager viewPager; private ViewPagerTabs tabs; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.volksempfaenger); actionBar = getSupportActionBar(); adapter = new Adapter(getSupportFragmentManager()); adapter.addFragment(getString(R.string.title_tab_subscriptions), SubscriptionGridFragment.class); // adding more fragments here viewPager = (ViewPager) findViewById(R.id.viewpager); viewPager.setAdapter(adapter); tabs = (ViewPagerTabs) findViewById(R.id.tabs); tabs.setViewPager(viewPager); } public static class Adapter extends FragmentPagerAdapter implements ViewPagerTabProvider { private FragmentManager fragmentManager; private ArrayList<Class<? extends Fragment>> fragments; private ArrayList<String> titles; public Adapter(FragmentManager fm) { super(fm); fragmentManager = fm; fragments = new ArrayList<Class<? extends Fragment>>(); titles = new ArrayList<String>(); } public void addFragment(String title, Class<? extends Fragment> fragment) { titles.add(title); fragments.add(fragment); } @Override public int getCount() { return fragments.size(); } public String getTitle(int position) { return titles.get(position); } @Override public Fragment getItem(int position) { try { return fragments.get(position).newInstance(); } catch (InstantiationException e) { Log.wtf(TAG, e); } catch (IllegalAccessException e) { Log.wtf(TAG, e); } return null; } @Override public Object instantiateItem(View container, int position) { FragmentTransaction fragmentTransaction = fragmentManager .beginTransaction(); Fragment f = getItem(position); fragmentTransaction.add(container.getId(), f); fragmentTransaction.commit(); return f; } } @Override public boolean onCreateOptionsMenu(Menu menu) { BaseActivity.addGlobalMenu(this, menu); return true; } @Override public boolean onOptionsItemSelected(MenuItem item) { return BaseActivity.handleGlobalMenu(this, item); } } Code of the fragment that shall have its own menu items: public class SubscriptionGridFragment extends Fragment { private GridView subscriptionList; private SubscriptionListAdapter adapter; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setHasOptionsMenu(true); } // ... @Override public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) { inflater.inflate(R.menu.subscription_list, menu); } @Override public boolean onOptionsItemSelected(MenuItem item) { // ... } }

    Read the article

  • Python constructor does weird things with optional parameters

    - by christangrant
    Can you help me understand of the behaviour and implications of the python __init__ constructor. It seems like when there is an optional parameter and you try and set an existing object to a new object the optional value of the existing object is preserved and copied. Ok that was confusing... so look at an example I concocted below. In the code below I am trying to make a tree structure with nodes and possibly many children . In the first class NodeBad, the constructor has two parameters, the value and any possible children. The second class NodeGood only takes the value of the node as a parameter. Both have an addchild method to add a child to a node. When creating a tree with the NodeGood class, it works as expected. However, when doing the same thing with the NodeBad class, it seems as though a child can only be added once! The code below will result in the following output: Good Tree 1 2 3 [< 3 >] Bad Tree 1 2 2 [< 2 >, < 3 >] Que Pasa? Here is the Example: #!/usr/bin/python class NodeBad: def __init__(self, value, c=[]): self.value = value self.children = c def addchild(self, node): self.children.append(node) def __str__(self): return '< %s >' % self.value def __repr__(self): return '< %s >' % self.value class NodeGood: def __init__(self, value): self.value = value self.children = [] def addchild(self, node): self.children.append(node) def __str__(self): return '< %s >' % self.value def __repr__(self): return '< %s >' % self.value if __name__ == '__main__': print 'Good Tree' ng = NodeGood(1) # Root Node rootgood = ng ng.addchild(NodeGood(2)) # 1nd Child ng = ng.children[0] ng.addchild(NodeGood(3)) # 2nd Child print rootgood.value print rootgood.children[0].value print rootgood.children[0].children[0].value print rootgood.children[0].children print 'Bad Tree' nb = NodeBad(1) # Root Node rootbad = nb nb.addchild(NodeBad(2)) # 1st Child nb = nb.children[0] nb.addchild(NodeBad(3)) # 2nd Child print rootbad.value print rootbad.children[0].value print rootbad.children[0].children[0].value print rootbad.children[0].children

    Read the article

< Previous Page | 401 402 403 404 405 406 407 408 409 410 411 412  | Next Page >