Game Development Section 1-drawing a simple image

Let's first draw a circle to understand the general surfaceview framework.

Circleactivity. JavaCode

Package yy. circle;

Import Android. App. activity;
Import Android. OS. Bundle;
Import Android. View. view;
Import Android. View. window;
Import Android. View. windowmanager;

Public class circleactivity extends activity {
/** Called when the activity is first created .*/
@ Override
Public void oncreate (bundle savedinstancestate ){
Super. oncreate (savedinstancestate );
This. requestwindowfeature (window. feature_no_title );
This. getwindow (). setflags (windowmanager. layoutparams. flag_fullscreen, windowmanager. layoutparams. flag_fullscreen );
Setcontentview (new circle (this ));
}

}

Circle. Java code

Package yy. circle;

Import Android. content. context;
Import Android. Graphics. Canvas;
Import Android. Graphics. color;
Import Android. Graphics. paint;
Import Android. Graphics. paintflagsdrawfilter;
Import Android. View. keyevent;
Import Android. View. motionevent;
Import Android. View. surfaceholder;
Import Android. View. surfaceview;
Import Android. View. surfaceholder. Callback;

Public class circle extends surfaceview implements callback, runnable {
Private surfaceholder SFH;
Private paint;
Private thread;
Private Boolean flag;
Private canvas;
Private int screenw, screenh;
Private paintflagsdrawfilter PFD = new paintflagsdrawfilter (0, paint. anti_alias_flag | paint. filter_bitmap_flag );
Public circle (context ){
Super (context );
SFH = This. getholder ();
SFH. addcallback (this );
Paint = new paint ();
Paint. setcolor (color. White );
System. Out. Print ("1 ");
Setfocusable (true );
}
Public void surfacecreated (surfaceholder holder ){
Screenw = This. getwidth ();
Screenh = This. getheight ();
Flag = true;
Thread = new thread (this );
Thread. Start ();
}
Public void mydraw (){
Try {
Canvas = SFH. lockcanvas ();
If (canvas! = NULL ){
Canvas. setdrawfilter (PFD );
Canvas. drawcolor (color. Black );
System. Out. Print ("2 ");
Canvas. drawcircle (50, 50, 50, paint );
System. Out. Print ("3 ");
}
} Catch (exception e ){}
Finally {
If (canvas! = NULL ){
SFH. unlockcanvasandpost (canvas );
}
}
}
Public Boolean ontouchevent (motionevent event ){
Return true;
}
Public Boolean onkeydown (INT keycode, keyevent event ){
Return super. onkeydown (keycode, event );
}
Public void logic (){}
Public void run (){
While (FLAG ){
Long start = system. currenttimemillis ();
Mydraw ();
Logic ();
Long end = system. currenttimemillis ();
Try {
If (end-start <50 ){
Thread. Sleep (50-(end-Start ));
}
} Catch (interruptedexception e ){
E. printstacktrace ();
}
}
}
Public void surfacechanged (surfaceholder holder, int format, int width, int height ){}
Public void surfacedestroyed (surfaceholder holder ){
Flag = false;
}

}