10 ticker of QT Study Notes

Bored learning ......

Write a ticker to trigger an event in the exercise.

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Some code is as follows:

Ticker. h

# Ifndef ticker_h <br/> # define ticker_h <br/> # include <qtgui/qwidget> <br/> namespace UI <br/>{< br/> class ticker; <br/>}< br/> class ticker: Public qwidget <br/>{< br/> q_object <br/> public: <br/> ticker (qwidget * parent = 0); <br/> ~ Ticker (); <br/> void settext (const qstring & newtext); <br/> qstring text () const; <br/> qsize sizehint () const; <br/> protected: <br/> void paintevent (qpaintevent * event); <br/> void timerevent (qtimerevent * evnet ); <br/> void showevent (qshowevent * event); <br/> void hideevent (qhideevent * event); <br/> PRIVATE: <br/> UI :: ticker * UI; <br/> qstring tickertext; <br/> int offset; // time interval <br/> int timerid; // timer id <br/> }; <br/> # endif // ticker_h

 

Ticker. cpp

# Include <qtgui> <br/> # include "ticker. H "<br/> # include" ui_ticker.h "<br/> ticker: ticker (qwidget * parent) <br/>: qwidget (parent), UI (new UI :: ticker) <br/>{< br/> UI-> setupui (this); <br/> offset = 0; <br/> timerid = 0; <br/>}< br/> ticker ::~ Ticker () <br/>{< br/> Delete UI; <br/>}< br/>/** <br/> set text <br/> */<br/> void ticker: settext (const qstring & newtext) <br/>{< br/> tickertext = newtext; <br/> Update (); <br/> updategeometry (); <br/>}< br/>/** <br/> obtain text content <br/> */<br/> qstring ticker: Text () const <br/>{< br/> return tickertext; <br/>}< br/>/** <br/> set the widget size <br/> */<br/> qsize ticker: sizehint () const <br/>{< br/> return fontmetrics (). size (0, text (); // fontmetrics (): returns the font metrics for the widget's current font <br/>}< br/>/** <br/> draw events <br/> */<br/> void ticker:: paintevent (qpaintevent *) <br/>{< br/> qpainter painter (this); <br/> int textwidth = fontmetrics (). width (text (); <br/> If (textwidth <1) <br/> return; <br/> int x =-offset; <br/> while (x <width () {<br/> painter. drawtext (x, 0, textwidth, height (), QT: alignleft | QT: alignvcenter, text (); // draw text <br/> X + = textwidth; <br/>}< br/>/** <br/> timer event <br/> */<br/> void ticker :: timerevent (qtimerevent * event) <br/>{< br/> If (Event-> timerid () = timerid) {<br/> ++ offset; <br/> If (Offset> = fontmetrics (). width (text () <br/> offset = 0; <br/> scroll (-1, 0 ); // scroll one pixel to the left <br/>} else {<br/> qwidget: timerevent (event ); <br/>}< br/>/** <br/> show events <br/> */<br/> void ticker :: showevent (qshowevent *) <br/>{< br/> timerid = starttimer (30); // starts a timer and returns a timer identifier, or returns zero if it cocould not start a timer. <br/>}< br/>/** <br/> hide events <br/> */<br/> void ticker: hideevent (qhideevent *) <br/>{< br/> killtimer (timerid); <br/> timerid = 0; <br/>}< br/>

 

The interface is as follows:

 

You can automatically scroll to the left... (How do you feel like the electricity bill is shown downstairs)

 

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Continue the boring summer vacation ....