ios - Cannot flip layer again,CALayer,CATransform3DRotate. -

what trying do :

1. click botton vertical flip.
2. click botton again, layer wil flip , on...

codes following :

    @interface viewcontroller (){         calayer *plane;     }     @end      @implementation viewcontroller      -(void)viewdidload     {         [super viewdidload];          [self addalayer];       }     - (void)addalayer{           plane                   =   [calayer layer];         plane.backgroundcolor   =   [[uicolor orangecolor] cgcolor];         //[plane insertsublayer:normalbackground atindex:0];          plane.opacity           =   1;         plane.frame             =   cgrectmake(0, 0, 300, 100);         plane.position          =   cgpointmake(250, 150);         plane.anchorpoint       =   cgpointmake(0.5, 0.5);         plane.bordercolor       =   [uicolor whitecolor].cgcolor;         plane.borderwidth       =   3;         plane.cornerradius      =   10;         [self.view.layer addsublayer:plane];      } - (ibaction)click:(id)sender {         bool isclicked                  =   ((uibutton*)sender).selected;         ((uibutton*)sender).selected    =   !((uibutton*)sender).selected;         catransform3d transfrom         =   catransform3didentity;         transfrom.m34                   =   -1.0/ 500;         if ( !isclicked )              transfrom                   =   catransform3drotate(transfrom, degtorad(180.0), 1, 0, 0);         else              transfrom                   =   catransform3drotate(transfrom, degtorad(-180.0), 1, 0, 0);          plane.transform                 =   transfrom;     } 

however, @ step 1, can see layer flip 180 degree , when click button again, there nothing happening.

did miss in middle? please help.

the code below gets sender's selected state only. , state set once. check modified code below.

// have global variable  bool isclicked   - (ibaction)click:(id)sender {         catransform3d transfrom         =   catransform3didentity;         transfrom.m34                   =   -1.0/ 500;         if ( !isclicked ) {             transfrom                   =   catransform3drotate(transfrom, degtorad(180.0), 1, 0, 0);         isclicked                       =   true;         }         else{              transfrom                   =   catransform3drotate(transfrom, degtorad(360.0), 1, 0, 0); // or can 0         isclicked                       =   false;         }         plane.transform                 =   transfrom;     }