ubuntu - Qt can not respond key Press event immediately -


environment: ubuntu, qt creator

in qt app, found qt doesn't respond key press event immediately, if wait while, responds.

i think blocking ui.

as know, if qt's component (qwidget etc.) being destroyed, qt ui blocked. have checked code, there no component being destroyed @ time i'm pressing up/down key. want know there other things can block qt ui.

{     ...     connect(webviewwidget, signal(loadfinished()), this, slot(additem()));     ... }  void additem() {     delete webviewwidget; // delete block ui?     mlistwidget = new scrollwidget();     mscrollarea = new scrollarea(this);     for(int i=0; i<datalen; i++)     {         mlistwidget->addsubitem(itemwidget);     } }  void keypressevent(qkeyevent *event) {     switch(event->key)     {     case up_key:         scroll up;         break;     case down_key:         scroll down;         break;     default:         break;     } }

  • destruction of objects not concern, unless doing lot of work in destructor. destroying webview may take long. should not destroying do. instrument delete (see code below) , see how long takes.

  • your own code may calling apis block. calling third party libraries? calling wait... methods in qt's own api?

    if you're unsure, can instrument every slot , every reimplemented virtual method xxxevent(...). you'd need instrument only slots , reimplemented qobject/qwidget methods, not every method in code.

  • you may producing event storm, perhaps posting lots of events in loop, or sending lot of signals hooked slots connected via qt::queuedconnection. make sure you're not calling repaint() within paintevent() example.

the instrumentation example below uses raii , easy apply. alternatively, can use profiler.

#include <qelapsedtimer> #define instrument() instrument instr__ument(__function__) #define instrumentlim(lim) instrument instr__ument(__function__, (lim))  class instrument {    qelapsedtimer timer;    int limit;    const char * function; public:    instrument(const char * name, int timelimitms = 20) :        function(name), limit(timelimitms) { timer.start(); }    ~instrument() {       if (timer.elapsed() > limit) {          qdebug("%s slow, took %d ms", function, timer.elapsed());       }    } }  void slot(...) {    instrument();    ...  }  void additem() {     instrument();     delete webviewwidget; // delete block ui?     mlistwidget = new scrollwidget();     mscrollarea = new scrollarea(this);     for(int i=0; i<datalen; i++)     {         mlistwidget->addsubitem(itemwidget);     } }

Comments

Post a Comment

Popular posts from this blog

java - Play! framework 2.0: How to display multiple image? -

i need display gallery of photos. here template: @(photos: list[photo]) @title = { <bold>gallery</bold> } @main(title,"photo"){ <ul class="thumbnails"> @for(photo <- photos) { <li class="span3"> <a href="#" class="thumbnail"> <img src="@photo.path" alt=""> </a> </li> } </ul> } and here controller method: public static result getphotos() { return ok(views.html.photo.gallery.render(photo.get())); } and here photo bean : @entity public class photo extends model { @id public long id; @required public string label; public string path; public photo(string path, string label) { this.path = path; this.label = label; } private static finder<long, photo> find = new finder<long, photo>( long.class, photo.class); public static list<phot...
Read more

gmail - Is there any documentation for read-only access to the Google Contacts API? -

i want read-only access user's google contacts. there stackoverflow member wanted this, , received following answer : yes, there is, use https://www.googleapis.com/auth/contacts.readonly scope , "view contacts". this exchange reference read-only access google contacts can find using google. simply using access token obtained attempt read usual google contacts api (i.e. https://www.google.com/m8/feeds ) fails insufficient permissions. similarly, using google contacts api on new target fails 404 errors (for example https://www.googleapis.com/auth/contacts.readonly/default/full ). is there documentation anywhere on how use api, or permissible way access google contacts api full read-write access?
Read more

php - Controller/JToolBar not working in Joomla 2.5 -

relevant code: jtoolbarhelper::custom('savecategories', 'save', '', 'save', false, false); ... <input type="hidden" name="controller" value="easyblogcontroller"> according can dig docs , own previous questions, should call savecategories() function in easyblogcontroller . i've tried setting value easyblog , easyblog.php (file name) current easyblogcontroller (class name). clicking on save button refreshes page. not redirect, echo or var_dump test code put in savecategories() function. var_dump ing jrequest::getvar('controller') , 'task' return correct values. creating controller object , using $controller->execute('task'); works. the values going depend on location of controller trying call, , have couple options here. typically there controller in base folder of component (likely components/com_easyblog) in file called controller.php , class name inside ...
Read more