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  • Implement a threading to prevent UI block on a bug in an async function

    - by Marcx
    I think I ran up againt a bug in an async function... Precisely the getDirectoryListingAsync() of the File class... This method is supposted to return an object containing the lists of files in a specified folder. I found that calling this method on a direcory with a lot of files (in my tests more than 20k files), after few seconds there is a block on the UI until the process is completed... I think that this method is separated in two main block: 1) get the list of files 2) create the array with the details of the files The point 1 seems to be async (for a few second the ui is responsive), then when the process pass from point 1 to point 2 the block of the UI occurs until the complete event is dispathed... Here's some (simple) code: private function checkFiles(dir:File):void { if (dir.exists) { dir.addEventListener( FileListEvent.DIRECTORY_LISTING, listaImmaginiLocale); dir.getDirectoryListingAsync(); // after this point, for the firsts seconds the UI respond well (point 1), // few seconds later (point 2) the UI is frozen } } private function listaImmaginiLocale( event:FileListEvent ):void { // from this point on the UI is responsive again... } Actually in my projects there are some function that perform an heavy cpu usage and to prevent the UI block I implemented a simple function that after some iteration will wait giving time to UI to be refreshed. private var maxIteration:int = 150000; private function sampleFunct(offset:int = 0) :void { if (offset < maxIteration) { // do something // call the recursive function using a timeout.. // if the offset in multiple by 1000 the function will wait 15 millisec, // otherwise it will be called immediately // 1000 is a random number for the pourpose of this example, but I usually change the // value based on how much heavy is the function itself... setTimeout(function():void{aaa(++offset);}, (offset%1000?15:0)); } } Using this method I got a good responsive UI without afflicting performance... I'd like to implement it into the getDirectoryListingAsync method but I don't know if it's possibile how can I do it where is the file to edit or extend.. Any suggestion???

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  • List of functions references

    - by Ockonal
    Hello, I'm using boost::function for making references to the functions. Can I make a list of references? For example: boost::function<bool (Entity &handle)> behaviorRef; And I need in a list of such pointers. For example: std::vector<behaviorRef> listPointers; Of course it's wrong code due to behaviorRef isn't a type. So the question is: how can I store a list of pointers for the function?

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  • How to build a control programatically?

    - by W_K
    I have custom control written in Java. For the sake of simplicity lets assume that it looks like this: public class HelloworldControl extends UIComponentBase { @Override public void decode(FacesContext context) { String cid = this.getClientId(context); ... super.decode(context); } @Override public void encodeBegin(FacesContext context) throws IOException { ResponseWriter writer = context.getResponseWriter(); writer.writeText("Hello world!", this); // I want a view!! } @Override public void encodeEnd(FacesContext context) throws IOException { ResponseWriter writer = context.getResponseWriter(); ... } public void restoreState(FacesContext context, Object state) { Object values[] = (Object[]) state; ... super.restoreState(context, values[0]); } public Object saveState(FacesContext context) { Object values[] = ... } } I would like to add programatically child control to it. For example I would like a child view control to render a view just under the Hellow world text. How can i do this? What is the standard procedure to build dynamically a control? To put it simply - I want programatically build a hierarchy of standard components and I want to attach it to my control.

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  • How to store and remove dynamically and automatic variable of generic data type in custum list data

    - by Vineel Kumar Reddy
    Hi I have created a List data structure implementation for generic data type with each node declared as following. struct Node { void *data; .... .... } So each node in my list will have pointer to the actual data(generic could be anything) item that should be stored in the list. I have following signature for adding a node to the list AddNode(struct List *list, void* eledata); the problem is when i want to remove a node i want to free even the data block pointed by *data pointer inside the node structure that is going to be freed. at first freeing of datablock seems to be straight forward free(data) // forget about the syntax..... But if data is pointing to a block created by malloc then the above call is fine....and we can free that block using free function int *x = (int*) malloc(sizeof(int)); *x = 10; AddNode(list,(void*)x); // x can be freed as it was created using malloc what if a node is created as following int x = 10; AddNode(list,(void*)&x); // x cannot be freed as it was not created using malloc Here we cannot call free on variable x!!!! How do i know or implement the functionality for both dynamically allocated variables and static ones....that are passed to my list.... Thanks in advance...

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  • IE8 + Jquery ajax call giving parsererror from dJango : for json data which seems valid in Firefox

    - by PlanetUnknown
    The ajax call works fine in FF. the data returned is in JSON here is an example from FF firebug - {"noProfiles": "No profiles have been created, lets start now !"} When I try to print the error in IE8 (& in compatibility modes as well), it says "parsererror". But the output seems to be valid JSON. Here is the ajax function call I'm making. Any pointers would be great ! $.ajax({ type: "GET", url: "/get_all_profile_details/", data: "", dataType: "json", beforeSend: function() {alert("before send called");}, success: function(jsonData) { alert("data received"); }, error: function(xhr, txt, err){ alert("xhr: " + xhr + "\n textStatus: " + txt + "\n errorThrown: " + err); } }); The alerts in the error function above give - xhr:<blank> textstatus:parsererror errorThrown: undefined Any pointers would be great ! Note : jquery : 1.3.2

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  • Constructor Overload Problem in C++ Inheritance

    - by metdos
    Here my code snippet: class Request { public: Request(void); ……….. } Request::Request(void) { qDebug()<<"Request: "<<"Hello World"; } class LoginRequest :public Request { public: LoginRequest(void); LoginRequest(QDomDocument); …………… } LoginRequest::LoginRequest(void) { qDebug()<<"LoginRequest: "<<"Hello World"; requestType=LOGIN; requestId=-1; } LoginRequest::LoginRequest(QDomDocument doc){ qDebug()<<"LoginRequest: "<<"Hello World with QDomDocument"; LoginRequest::LoginRequest(); xmlDoc_=doc; } When call constructor of Overrided LoginRequest LoginRequest *test=new LoginRequest(doc); I came up with this result: Request: Hello World LoginRequest: Hello World with QDomDocument Request: Hello World LoginRequest: Hello World Obviously both constructor of LoginRequest called REquest constructor. Is there any way to cape with this situation? I can construct another function that does the job I want to do and have both constructors call that function. But I wonder is there any solution?

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  • why when I delete a parent on a one to many relationship on grails the beforeInsert event is called

    - by nico
    hello, I have a one to many relationship and when I try to delete a parent that haves more than one child the berforeInsert event gets called on the frst child. I have some code in this event that I mean to call before inserting a child, not when i'm deleting the parent! any ideas on what might be wrong? the entities: class MenuItem { static constraints = { name(blank:false,maxSize:200) category() subCategory(nullable:true, validator:{ val, obj -> if(val == null){ return true }else{ return obj.category.subCategories.contains(val)? true : ['invalid.category.no.subcategory'] } }) price(nullable:true) servedAtSantaMonica() servedAtWestHollywood() highLight() servedAllDay() dateCreated(display:false) lastUpdated(display:false) } static mapping = { extras lazy:false } static belongsTo = [category:MenuCategory,subCategory:MenuSubCategory] static hasMany = [extras:MenuItemExtra] static searchable = { extras component: true } String name BigDecimal price Boolean highLight = false Boolean servedAtSantaMonica = false Boolean servedAtWestHollywood = false Boolean servedAllDay = false Date dateCreated Date lastUpdated int displayPosition void moveUpDisplayPos(){ def oldDisplayPos = MenuItem.get(id).displayPosition if(oldDisplayPos == 0){ return }else{ def previousItem = MenuItem.findByCategoryAndDisplayPosition(category,oldDisplayPos - 1) previousItem.displayPosition += 1 this.displayPosition = oldDisplayPos - 1 this.save(flush:true) previousItem.save(flush:true) } } void moveDownDisplayPos(){ def oldDisplayPos = MenuItem.get(id).displayPosition if(oldDisplayPos == MenuItem.countByCategory(category) - 1){ return }else{ def nextItem = MenuItem.findByCategoryAndDisplayPosition(category,oldDisplayPos + 1) nextItem.displayPosition -= 1 this.displayPosition = oldDisplayPos + 1 this.save(flush:true) nextItem.save(flush:true) } } String toString(){ name } def beforeInsert = { displayPosition = MenuItem.countByCategory(category) } def afterDelete = { def otherItems = MenuItem.findAllByCategoryAndDisplayPositionGreaterThan(category,displayPosition) otherItems.each{ it.displayPosition -= 1 it.save() } } } class MenuItemExtra { static constraints = { extraOption(blank:false, maxSize:200) extraOptionPrice(nullable:true) } static searchable = true static belongsTo = [menuItem:MenuItem] BigDecimal extraOptionPrice String extraOption int displayPosition void moveUpDisplayPos(){ def oldDisplayPos = MenuItemExtra.get(id).displayPosition if(oldDisplayPos == 0){ return }else{ def previousExtra = MenuItemExtra.findByMenuItemAndDisplayPosition(menuItem,oldDisplayPos - 1) previousExtra.displayPosition += 1 this.displayPosition = oldDisplayPos - 1 this.save(flush:true) previousExtra.save(flush:true) } } void moveDownDisplayPos(){ def oldDisplayPos = MenuItemExtra.get(id).displayPosition if(oldDisplayPos == MenuItemExtra.countByMenuItem(menuItem) - 1){ return }else{ def nextExtra = MenuItemExtra.findByMenuItemAndDisplayPosition(menuItem,oldDisplayPos + 1) nextExtra.displayPosition -= 1 this.displayPosition = oldDisplayPos + 1 this.save(flush:true) nextExtra.save(flush:true) } } String toString(){ extraOption } def beforeInsert = { if(menuItem){ displayPosition = MenuItemExtra.countByMenuItem(menuItem) } } def afterDelete = { def otherExtras = MenuItemExtra.findAllByMenuItemAndDisplayPositionGreaterThan(menuItem,displayPosition) otherExtras.each{ it.displayPosition -= 1 it.save() } } }

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  • Function template accepting nothing less than a bidirectional iterator or a pointer

    - by san
    I need a function template that accepts two iterators that could be pointers. If the two arguments are random_access iterators I want the return type to be an object of std::iterator<random_access_iterator_tag, ...> type else a std::iterator<bidirectional_iterator_tag, ...> type. I also want the code to refuse compilation if the arguments are neither a bidirectional iterator, nor a pointer. I cannot have dependency on third party libraries e.g. Boost Could you help me with the signature of this function so that it accepts bidirectional iterators as well as pointers, but not say input_iterator, output_iterator, forward_iterators. One partial solution I can think of is the following template<class T> T foo( T iter1, T iter2) { const T tmp1 = reverse_iterator<T>(iter1); const T tmp2 = reverse_iterator<T>(iter2); // do something } The idea is that if it is not bidirectional the compiler will not let me construct a reverse_iterator from it.

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  • Displaying modal view in Objective-C

    - by kpower
    I'm trying to display Modal View in my app. I have subclass of UIViewController that has only the "Done" button (UIButton created with IB and linked with XCode). .h @interface myModalVC : UIViewController { UIButton *bDone; } @property (nonatomic, retain) IBOutlet UIButton *bDone; - (IBAction)bDoneTouchDown:(id)sender; @end .m #import "myModalVC.h" @implementation myModalVC @synthesize bDone; - (void)dealloc { [bDone release]; [super dealloc]; } - (void)viewDidLoad { [super viewDidLoad]; } - (void)viewDidUnload { } - (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation { return (UIInterfaceOrientationLandscapeLeft == interfaceOrientation || UIInterfaceOrientationLandscapeRight == interfaceOrientation); } - (void)didReceiveMemoryWarning { [super didReceiveMemoryWarning]; } - (IBAction)bDoneTouchDown:(id)sender { [self.parentViewController dismissModalViewControllerAnimated:YES]; } @end I'm trying to display modal view with this code (from my main view): myModalVC *temp = [[[myModalVC alloc] initWithNibName:@"myModalVC" bundle:[NSBundle mainBundle]] autorelease]; [self presentModalViewController:temp animated:YES]; If this code is placed in some method, that responds to button touches - everything is fine. But when I place it to some other method (called during some processes in my app) - modal view is displayed without problems, but when I press (touch) "Done" button, application crashes with "Program received signal: “EXC_BAD_ACCESS”." What am I doing wrong?

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  • SWT Problem with MouseTrackListener and Shell

    - by Krt_Malta
    Hi! I'm developing an Eclipse plug-in and I have a problem which is reproduced in this small SWT application: public static void main(String[] args) { Display display = new Display(); Shell shell = new Shell(display); Text text = new Text(shell, SWT.MULTI | SWT.WRAP | SWT.READ_ONLY | SWT.V_SCROLL); text.setText("Hello"); shell.setLayout(new FillLayout()); shell.addMouseTrackListener(new MouseTrackListener() { public void mouseEnter(MouseEvent arg0) { System.out.println("mouseEnter"); } public void mouseExit(MouseEvent arg0) { System.out.println("mouseExit"); } public void mouseHover(MouseEvent arg0) { System.out.println("mouseHover"); } }); // Display the window shell.open(); while (!shell.isDisposed()) { if (!display.readAndDispatch()) { display.sleep(); } } display.dispose(); } As you can see I'm creating a shell and putting a Textbox inside it and putting it all across the shell. Then I attach a MouseTrackListener to the shell. The events don't fire (as in when I hover in the shell "mouseHover" is not printed etc). When I remove the Textbox the events fire. Can anyone tell me where the problem lies please? I don't want to attach a listener to the textbox but to the shell. I'll really appreciate the help because I've been trying to trace it for quite some time now. Thanks and regards, Krt_Malta

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  • Fading in and fading out for a form

    - by karthik
    hi i have a requirement in which my form is transparent,if my mouse enters into it the form should became visible,if my mouse leaves out of the form it becomes transparent, i have three different controls placed in my form , each controls mouse leave and mouse enter is the same that of the form . if my mouse enters into the form and enters into a control form_mouseleaveevent and control_mouseenterd gets fired so iam not able to achieve it,how to overcome this. below is the piece of code for this: private void TransToOpac() { if (!isTransparent) return; if (TtoOON == false ) { TtoOON = true; for (i = this.Opacity; i <= 1; i = i + 0.02) { this.Opacity = i; Thread.Sleep(50); } isTransparent = false; TtoOON = false; } } private void OpacToTrans() { if (isTransparent) return; if (OtoTON == false ) { OtoTON = true; for (i = this.Opacity; i >= 0.5; i = i - 0.02) { this.Opacity = i; Thread.Sleep(50); } isTransparent = true; OtoTON = false; } } private void OnMouseEntered(object sender, EventArgs e) { TransToOpac(); } private void OnMouseLeft(object sender, EventArgs e) { OpacToTrans(); }

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  • Java Concurrency in practice sample question

    - by andy boot
    I am reading "Java Concurrency in practice" and looking at the example code on page 51. This states that if a thread has references to a shared object then other threads may be able to access that object before the constructor has finished executing. I have tried to put this into practice and so I wrote this code thinking that if I ran it enough times a RuntimeException("World is f*cked") would occur. But it isn't doing. Is this a case of the Java spec not guaranting something but my particular implementation of java guaranteeing it for me? (java version: 1.5.0 on Ubuntu) Or have I misread something in the book? Code: (I expect an exception but it is never thrown) public class Threads { private Widgit w; public static void main(String[] s) throws Exception { while(true){ Threads t = new Threads(); t.runThreads(); } } private void runThreads() throws Exception{ new Checker().start(); w = new Widgit((int)(Math.random() * 100) + 1); } private class Checker extends Thread{ private static final int LOOP_TIMES = 1000; public void run() { int count = 0; for(int i = 0; i < LOOP_TIMES; i++){ try { w.checkMe(); count++; } catch(NullPointerException npe){ //ignore } } System.out.println("checked: "+count+" times out of "+LOOP_TIMES); } } private static class Widgit{ private int n; private int n2; Widgit(int n) throws InterruptedException{ this.n = n; Thread.sleep(2); this.n2 = n; } void checkMe(){ if (n != n2) { throw new RuntimeException("World is f*cked"); } } } }

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  • Java/Hibernate using interfaces over the entities.

    - by Dennetik
    I am using annoted Hibernate, and I'm wondering whether the following is possible. I have to set up a series of interfaces representing the objects that can be persisted, and an interface for the main database class containing several operations for persisting these objects (... an API for the database). Below that, I have to implement these interfaces, and persist them with Hibernate. So I'll have, for example: public interface Data { public String getSomeString(); public void setSomeString(String someString); } @Entity public class HbnData implements Data, Serializable { @Column(name = "some_string") private String someString; public String getSomeString() { return this.someString; } public void setSomeString(String someString) { this.someString = someString; } } Now, this works fine, sort of. The trouble comes when I want nested entities. The interface of what I'd want is easy enough: public interface HasData { public Data getSomeData(); public void setSomeData(Data someData); } But when I implement the class, I can follow the interface, as below, and get an error from Hibernate saying it doesn't know the class "Data". @Entity public class HbnHasData implements HasData, Serializable { @OneToOne(cascade = CascadeType.ALL) private Data someData; public Data getSomeData() { return this.someData; } public void setSomeData(Data someData) { this.someData = someData; } } The simple change would be to change the type from "Data" to "HbnData", but that would obviously break the interface implementation, and thus make the abstraction impossible. Can anyone explain to me how to implement this in a way that it will work with Hibernate?

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  • How do I insert this subclass into my code?

    - by BamsBamx
    This is a very noob question so I hope you can help me with this... This is my built code: public class PantallaOpciones extends PreferenceActivity { private SharedPreferences preferences; @Override public void onCreate(Bundle savedInstanceState) { preferences = PreferenceManager.getDefaultSharedPreferences(this); findPreference("speechkeycode").setOnPreferenceClickListener(keycodedialog); Preference.OnPreferenceClickListener keycodedialog = new Preference.OnPreferenceClickListener(){ public boolean onPreferenceClick(Preference preference){ keycodedialog(); return false; }}; } private void keycodedialog(){ final Dialog dialog = new Dialog(this); dialog.setContentView(R.layout.keycodedialog); dialog.setTitle("Speech keycode"); final TextView keypresstext = (TextView) findViewById(R.id.keypresstext); Button savekeycode = (Button) dialog.findViewById(R.id.btnsavekeycode); savekeycode.setOnClickListener(new OnClickListener() { public void onClick(View v) { dialog.dismiss(); } }); Button resetkeycode = (Button) dialog.findViewById(R.id.btnresetvalue); resetkeycode.setOnClickListener(new OnClickListener() { public void onClick(View v) { dialog.dismiss(); } }); dialog.show(); } Okay, now I want to add this code to dialog: public boolean onKeyDown(int keyCode, KeyEvent event) { //SOME STUFF return super.onKeyDown(keyCode, event); } So I want to listen to a keypress when dialog is opened and show the keycode of hardware press by using textview.settext()... The question is: how do I insert public boolean onKeyDown into the dialog??? Thanks in advance!! :)

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  • How to resize a UISwitch?

    - by mshsayem
    I have made a custom UISwitch (from this post). But the problem is, my custom texts are a bit long. Is there any way to resize the switch? [I tried setBounds, did not work] Edit: Here is the code I used: @interface CustomUISwitch : UISwitch - (void) setLeftLabelText: (NSString *) labelText; - (void) setRightLabelText: (NSString *) labelText; @end @implementation CustomUISwitch - (UIView *) slider { return [[self subviews] lastObject]; } - (UIView *) textHolder { return [[[self slider] subviews] objectAtIndex:2]; } - (UILabel *) leftLabel { return [[[self textHolder] subviews] objectAtIndex:0]; } - (UILabel *) rightLabel { return [[[self textHolder] subviews] objectAtIndex:1]; } - (void) setLeftLabelText: (NSString *) labelText { [[self leftLabel] setText:labelText]; } - (void) setRightLabelText: (NSString *) labelText { [[self rightLabel] setText:labelText]; } @end mySwitch = [[CustomUISwitch alloc] initWithFrame:CGRectZero]; //Tried these, but did not work //CGRect aFrame = mySwitch.frame; //aFrame.size.width = 200; //aFrame.size.height = 100; //mySwitch.frame = aFrame; [mySwitch setLeftLabelText: @"longValue1"]; [mySwitch setRightLabelText: @"longValue2"];

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  • Ensuring that all callbacks were completed before sending a new request through a DuplexChannel usin

    - by Etan
    I am experiencing some issues when using a Callback in a WCF project. First, the server invokes some function Foo on the client which then forwards the request to a Windows Forms GUI: GUI CLASS delegate void DoForward(); public void ForwardToGui() { if (this.cmdSomeButton.InvokeRequired) { DoForward d = new DoForward(ForwardToGui); this.Invoke(d); } else { Process(); // sets result variable in callback class as soon as done } } } CALLBACK CLASS object _m = new object(); private int _result; public int result { get { return _result; } set { _result = value; lock(_m) { Monitor.PulseAll(_m); } } } [OperationContract] public int Foo() { result = 0; Program.Gui.ForwardToGui(); lock(_m) { Monitor.Wait(_m, 30000); } return result; } The problem now is that the user should be able to cancel the process, which doesn't work properly: SERVER INTERFACE [OperationContract] void Cleanup(); GUI CLASS private void Gui_FormClosed(object sender, EventArgs e) { Program.callbackclass.nextAction = -1; // so that the monitor pulses and Foo() returns Program.server.Cleanup(); } The problem with this is that Cleanup() hangs. However, when I close the form when Process() is not running, it works properly. The source seems to be that the Cleanup() is called before the monitor pulses etc and therefore a new request is sent to the server before the last request from the server has not yet been responded. How can I solve this problem? How can I ensure before calling Cleanup() that no Foo() is currently being executed?

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  • Android Camera intent creating two files

    - by Kyle Ramstad
    I am making a program that takes a picture and then shows it's thumbnail. When using the emulator all goes well and the discard button deletes the photo. But on a real device the camera intent saves the image at the imageUri variable and a second one that is named like if I had just opened up the camera and took a picture by itself. private static final int CAMERA_PIC_REQUEST = 1337; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.camera); //start camera values = new ContentValues(); values.put(MediaStore.Images.Media.TITLE, "New Picture"); values.put(MediaStore.Images.Media.DESCRIPTION,"From your Camera"); imageUri = getContentResolver().insert(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, values); image = (ImageView) findViewById(R.id.ImageView01); Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE); intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri); startActivityForResult(intent, CAMERA_PIC_REQUEST); //save the image buttons Button save = (Button) findViewById(R.id.Button01); Button close = (Button) findViewById(R.id.Button02); } @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { if (requestCode == CAMERA_PIC_REQUEST && resultCode == RESULT_OK) { try{ thumbnail = MediaStore.Images.Media.getBitmap(getContentResolver(), imageUri); image.setImageBitmap(thumbnail); } catch(Exception e){ e.printStackTrace(); } } else{ finish(); } } public void myClickHandler(View view) { switch (view.getId()) { case R.id.Button01: finish(); break; case R.id.Button02: dicard(); } } private void dicard(){ getContentResolver().delete(imageUri, null, null); finish(); }

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  • MMGR Questions, code use and thread-saftey

    - by chadb
    1) Is MMGR thread safe? 2) I was hoping someone could help me understand some code. I am looking at something where a macro is used, but I don't understand the macro. I know it contains a function call and an if check, however, the function is a void function. How does wrapping "(m_setOwner (FILE,_LINE_,FUNCTION),false)" ever change return types? #define someMacro (m_setOwner(__FILE__,__LINE__,__FUNCTION__),false) ? NULL : new ... void m_setOwner(const char *file, const unsigned int line, const char *func); 3) What is the point of the reservoir? 4) On line 770 ("void *operator new(size_t reportedSize)" there is the line "// ANSI says: allocation requests of 0 bytes will still return a valid value" Who/what is ANSI in this context? Do they mean the standards? 5) This is more of C++ standards, but where does "reportedSize" come from for "void *operator new(size_t reportedSize)"? 6) Is this the code that is actually doing the allocation needed? "au-actualAddress = malloc(au-actualSize);"

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  • Linking a template class using another template class (error LNK2001)

    - by Luís Guilherme
    I implemented the "Strategy" design pattern using an Abstract template class, and two subclasses. Goes like this: template <class T> class Neighbourhood { public: virtual void alter(std::vector<T>& array, int i1, int i2) = 0; }; and template <class T> class Swap : public Neighbourhood<T> { public: virtual void alter(std::vector<T>& array, int i1, int i2); }; There's another subclass, just like this one, and alter is implemented in the cpp file. Ok, fine! Now I declare another method, in another class (including neighbourhood header file, of course), like this: void lSearch(/*parameters*/, Neighbourhood<LotSolutionInformation> nhood); It compiles fine and cleanly. When starting to link, I get the following error: 1>SolverFV.obj : error LNK2001: unresolved external symbol "public: virtual void __thiscall lsc::Neighbourhood<class LotSolutionInformation>::alter(class std::vector<class LotSolutionInformation,class std::allocator<class LotSolutionInformation> > &,int,int)" (?alter@?$Neighbourhood@VLotSolutionInformation@@@lsc@@UAEXAAV?$vector@VLotSolutionInformation@@V?$allocator@VLotSolutionInformation@@@std@@@std@@HH@Z)

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  • typedef struct, circular dependency, forward definitions

    - by BlueChip
    The problem I have is a circular dependency issue in C header files ...Having looked around I suspect the solution will have something to do with Forward Definitions, but although there are many similar problems listed, none seem to offer the information I require to resolve this one... I have the following 5 source files: // fwd1.h #ifndef __FWD1_H #define __FWD1_H #include "fwd2.h" typedef struct Fwd1 { Fwd2 *f; } Fwd1; void fwd1 (Fwd1 *f1, Fwd2 *f2) ; #endif // __FWD1_H . // fwd1.c #include "fwd1.h" #include "fwd2.h" void fwd1 (Fwd1 *f1, Fwd2 *f2) { return; } . // fwd2.h #ifndef __FWD2_H #define __FWD2_H #include "fwd1.h" typedef struct Fwd2 { Fwd1 *f; } Fwd2; void fwd2 (Fwd1 *f1, Fwd2 *f2) ; #endif // __FWD2_H . // fwd2.c #include "fwd1.h" #include "fwd2.h" void fwd2 (Fwd1 *f1, Fwd2 *f2) { return; } . // fwdMain.c #include "fwd1.h" #include "fwd2.h" int main (int argc, char** argv, char** env) { Fwd1 *f1 = (Fwd1*)0; Fwd2 *f2 = (Fwd2*)0; fwd1(f1, f2); fwd2(f1, f2); return 0; } Which I am compiling with the command: gcc fwdMain.c fwd1.c fwd2.c -o fwd -Wall I have tried several ideas to resolve the compile errors, but have only managed to replace the errors with other errors ...How do I resolve the circular dependency issue with the least changes to my code? ...Ideally, as a matter of coding style, I would like to avoid putting the word "struct" all over my code.

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  • virtual methods and template classes

    - by soxs060389
    Hi I got over a problem, I think a very specific one. I've got 2 classes, a B aseclass and a D erived class (from B aseclass). B is a template class ( or class template) and has a pure virtual method virutal void work(const T &dummy) = 0; The D erived class is supposed to reimplement this, but as D is Derived from B rather than D being another template class, the compiler spits at me that virtual functions and templates don't work at once. Any ideas how to acomplish what I want? I am thankfull for any thoughts and Ideas, especially if you allready worked out that problem this class is fixed aka AS IS, I can not edit this without breaking existing code base template <typename T> class B { public: ... virtual void work(const T &dummy) = 0; .. }; take int* as an example class D : public B<int*>{ ... virtual void work(const int* &dummy){ /* put work code here */ } .. }; Edit: The compiler tells me, that void B<T>::work(const T&) [with T = int*] is pure virtual within D

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  • base destructor called twice after derived object?

    - by sil3nt
    hey there, why is the base destructor called twice at the end of this program? #include <iostream> using namespace std; class B{ public: B(){ cout << "BC" << endl; x = 0; } virtual ~B(){ cout << "BD" << endl; } void f(){ cout << "BF" << endl; } virtual void g(){ cout << "BG" << endl; } private: int x; }; class D: public B{ public: D(){ cout << "dc" << endl; y = 0; } virtual ~D(){ cout << "dd" << endl; } void f(){ cout << "df" << endl; } virtual void g(){ cout << "dg" << endl; } private: int y; }; int main(){ B b, * bp = &b; D d, * dp = &d; bp->f(); bp->g(); bp = dp; bp->f(); bp->g(); }

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  • Splitting a C++ class into files now won't compile.

    - by vgm64
    Hi. I am teaching myself to write classes in C++ but can't seem to get the compilation to go through. If you can help me figure out not just how, but why, it would be greatly appreciated. Thank you in advance! Here are my three files: make_pmt.C #include <iostream> #include "pmt.h" using namespace std; int main() { CPMT *pmt = new CPMT; pmt->SetVoltage(900); pmt->SetGain(2e6); double voltage = pmt->GetVoltage(); double gain= pmt->GetGain(); cout << "The voltage is " << voltage << " and the gain is " << gain << "." <<endl; return 0; } pmt.C #include "pmt.h" using namespace std; class CPMT { double gain, voltage; public: double GetGain() {return gain;} double GetVoltage() {return voltage;} void SetGain(double g) {gain=g;} void SetVoltage(double v) {voltage=v;} }; pmt.h #ifndef PMT_H #define PMT_H 1 using namespace std; class CPMT { double gain, voltage; public: double GetGain(); double GetVoltage(); void SetGain(double g); void SetVoltage(double v); }; #endif And for reference, I get a linker error (right?): Undefined symbols: "CPMT::GetVoltage()", referenced from: _main in ccoYuMbH.o "CPMT::GetGain()", referenced from: _main in ccoYuMbH.o "CPMT::SetVoltage(double)", referenced from: _main in ccoYuMbH.o "CPMT::SetGain(double)", referenced from: _main in ccoYuMbH.o ld: symbol(s) not found collect2: ld returned 1 exit status

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  • Is this a correct way to stop Execution Task

    - by Yan Cheng CHEOK
    I came across code to stop execution's task. private final ExecutorService executor = Executors.newSingleThreadExecutor(); public void stop() { executor.shutdownNow(); try { executor.awaitTermination(100, TimeUnit.DAYS); } catch (InterruptedException ex) { log.error(null, ex); } } public Runnable getRunnable() { return new Runnable() { public void run() { while (!Thread.currentThread().isInterrupted()) { // What if inside fun(), someone try to clear the interrupt flag? // Say, through Thread.interrupted(). We will stuck in this loop // forever. fun(); } } }; } I realize that, it is possible for Runnable to be in forever loop, as Unknown fun may Thread.sleep, clear the interrupt flag and ignore the InterruptedException Unknown fun may Thread.interrupted, clear the interrupt flag. I was wondering, is the following way correct way to fix the code? private final ExecutorService executor = Executors.newSingleThreadExecutor(); private volatile boolean flag = true; public void stop() { flag = false; executor.shutdownNow(); try { executor.awaitTermination(100, TimeUnit.DAYS); } catch (InterruptedException ex) { log.error(null, ex); } } public Runnable getRunnable() { return new Runnable() { public void run() { while (flag && !Thread.currentThread().isInterrupted()) { // What if inside fun(), someone try to clear the interrupt flag? // Say, through Thread.interrupted(). We will stuck in this loop // forever. fun(); } } }; }

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