objective c - How to change frame of uiview is using autolayout in iOS? -

i added 1 view in xib, set autolayout. when run, want to change frame of view. know if using autolayout, need set translatesautoresizingmaskintoconstraints = yes in code. have done that, create new frame view shows warning message in console:

    @ least 1 of constraints in following list 1 don't want. try this: (1) @ each constraint , try figure out don't expect; (2) find code added unwanted constraint or constraints , fix it. (note: if you're seeing nsautoresizingmasklayoutconstraints don't understand, refer documentation uiview property translatesautoresizingmaskintoconstraints)  (     "<nsibprototypinglayoutconstraint:0x16e4b750 'ib auto generated @ build time view fixed frame' v:|-(0)-[uiview:0x16ed3c30]   (names: '|':uiview:0x16ee06b0 )>",     "<nsautoresizingmasklayoutconstraint:0x16e19e30 h=-&- v=-&- uiview:0x16ed3c30.midy == uiview:0x16ee06b0.midy + 44>",     "<nsautoresizingmasklayoutconstraint:0x16e19e60 h=-&- v=-&- uiview:0x16ed3c30.height == uiview:0x16ee06b0.height>" )  attempt recover breaking constraint  <nsibprototypinglayoutconstraint:0x16e4b750 'ib auto generated @ build time view fixed frame' v:|-(0)-[uiview:0x16ed3c30]   (names: '|':uiview:0x16ee06b0 )>  break on objc_exception_throw catch in debugger. methods in uiconstraintbasedlayoutdebugging category on uiview listed in <uikit/uiview.h> may helpful. 

this code create new frame, want origin of y equal 0.

self.leftview.frame= cgrectmake(0, 0, 40, self.view.frame.size.height); 

how can fix bug? please give advice. much.

if understand correctly, think need use stored nslayoutconstraint variable in class, update constraint's constant value 0 make uiview slide top.

also, when you're using autolayout, set:

myview.translateautoresizingmaskintoconstraint = no; 

that's no instead of yes.

so example like:

@interface myviewcontroller() {     nslayoutconstraint *myviewtopconstraint; }  @end  @implementation myviewcontroller  -(void)setupmyconstraintsmethod {     ...      // ---------------------------------------------------------------     // constraint here says "myview" top edge should pinned     // top edge of view controller's view offset     // of 50 pixels.      // ---------------------------------------------------------------     nslayoutconstraint *myviewtopconstraint = [nslayoutconstraint constraintwithitem:self.myview attribute:nslayoutattributetop relatedby:nslayoutrelationequal toitem:self.view attribute:nslayoutattributetop multiplier:1.0 constant:50.0];      [self.view addconstraint:myviewtopconstraint]; }  -(void)buttonpressed:(id)sender {     // ------------------------------------------------------------     // want myview's top edge @ top of     // view controller's view, set constant 0     // ------------------------------------------------------------     myviewtopconstraint.constant = 0;      // animates sliding of "myview"     [uiview animatewithduration:0.5 animations:^{         [self.view layoutifneeded];     }]; }  @end