ios - UIButton inside UIVIew not centered in iPhone app -

i'm setting custom uiview programmatically contain several uibutton , working fine. i'm trying center uibutton inside sub-custom uiview i've created programmatically. here code i'm using

//uiview used parent blurreffectview blurredpowerdown = [[uiview alloc] initwithframe:cgrectmake(0, 0, [[uiscreen mainscreen] bounds].size.width, [[uiscreen mainscreen] bounds].size.height)];                     blurredpowerdown.backgroundcolor = [uicolor clearcolor];                      //i'm calling applying custom view on top of other application (yes jailbreak development issue not related @ at                     window = [[uiwindow alloc] initwithframe:[[uiscreen mainscreen] bounds]];                     window.windowlevel = uiwindowlevelalert + 2;                     [window sethidden:no];                     [window setalpha:1.0];                     [window setbackgroundcolor:[uicolor clearcolor]];                     [window addsubview:blurredpowerdown];                      //code blur depending of behind view                     blur = [uiblureffect effectwithstyle:uiblureffectstyledark];                     blureffectview = [[uivisualeffectview alloc]initwitheffect:blur];                     blureffectview.frame = blurredpowerdown.bounds;                     blureffectview.autoresizingmask = uiviewautoresizingflexiblewidth | uiviewautoresizingflexibleheight;                     [blureffectview setalpha:0.0];                     [blurredpowerdown addsubview:blureffectview];                      [uiview animatewithduration:0.5 delay:0.0 options:uiviewanimationoptioncurveeasein animations:^{              [blureffectview setalpha:1.0];              }             completion:^(bool finished) {              }];                      //this view use center button add (in red on following picture)                     centerview = [[uiview alloc] init];                     [centerview settranslatesautoresizingmaskintoconstraints:no];                     centerview.backgroundcolor = [uicolor redcolor];                      [blureffectview addsubview:centerview];                      [blureffectview addconstraint:[nslayoutconstraint constraintwithitem:centerview                                                       attribute:nslayoutattributewidth                                                       relatedby:nslayoutrelationequal                                                          toitem:blureffectview                                                       attribute:nslayoutattributewidth                                                      multiplier:0.7                                                        constant:0]];                      [blureffectview addconstraint:[nslayoutconstraint constraintwithitem:centerview                                                       attribute:nslayoutattributeheight                                                       relatedby:nslayoutrelationequal                                                          toitem:blureffectview                                                       attribute:nslayoutattributeheight                                                      multiplier:0.5                                                        constant:0]];                       [blureffectview addconstraint:[nslayoutconstraint constraintwithitem:centerview                                                       attribute:nslayoutattributecenterx                                                       relatedby:nslayoutrelationequal                                                          toitem:blureffectview                                                       attribute:nslayoutattributecenterx                                                      multiplier:1.0                                                        constant:0.0]];                       [blureffectview addconstraint:[nslayoutconstraint constraintwithitem:centerview                                                       attribute:nslayoutattributecentery                                                       relatedby:nslayoutrelationequal                                                          toitem:blureffectview                                                       attribute:nslayoutattributecentery                                                      multiplier:1.0                                                        constant:0.0]];                      //and button cause me issue                     uibutton *cancelbutton = [uibutton buttonwithtype:uibuttontypecustom];                     [cancelbutton addtarget:self action:@selector(cancelview) forcontrolevents:uicontroleventtouchupinside];                     [cancelbutton settitle:@"cancel" forstate:uicontrolstatenormal];                     cancelbutton.frame = cgrectmake(0, 0, 80, 80);                     cancelbutton.clipstobounds = yes;                     cancelbutton.layer.cornerradius = 80/2.0f;                     cancelbutton.layer.bordercolor=[uicolor whitecolor].cgcolor;                     cancelbutton.layer.borderwidth=2.0f;                       [centerview addsubview:cancelbutton];                      //constraints removed per udits suggestion                     [centerview addconstraint:[nslayoutconstraint constraintwithitem:cancelbutton                                                       attribute:nslayoutattributewidth                                                       relatedby:nslayoutrelationequal                                                          toitem:centerview                                                       attribute:nslayoutattributewidth                                                      multiplier:1.0                                                        constant:0]];                      [centerview addconstraint:[nslayoutconstraint constraintwithitem:cancelbutton                                                       attribute:nslayoutattributeheight                                                       relatedby:nslayoutrelationequal                                                          toitem:centerview                                                       attribute:nslayoutattributeheight                                                      multiplier:1.0                                                        constant:0]];                       [centerview addconstraint:[nslayoutconstraint constraintwithitem:cancelbutton                                                       attribute:nslayoutattributecenterx                                                       relatedby:nslayoutrelationequal                                                          toitem:centerview                                                       attribute:nslayoutattributecenterx                                                      multiplier:1.0                                                        constant:0.0]];                       [centerview addconstraint:[nslayoutconstraint constraintwithitem:cancelbutton                                                       attribute:nslayoutattributecentery                                                       relatedby:nslayoutrelationequal                                                          toitem:centerview                                                       attribute:nslayoutattributecentery                                                      multiplier:1.0                                                        constant:0.0]]; 

here screenshot of do

i don't understand why uibutton stay in top left (like if has no placement constraints have added them !)

i'm desperated !

thanks in advance

edit: if set cancelbutton.center = centerview.center; here get:

edit2: suggested, i've set cancelbutton.translatesautoresizingmaskintoconstraints = no; here result:

edit3: advance ^^ @udits suggestion (delete height , width constraints) button centered border strange

you should disable translation autoresizingmask constraints button:

cancelbutton.translatesautoresizingmaskintoconstraints = no; 

addition: if want set width , height of button 80px, should replace 2 first constraints cancelbutton on these:

[cancelbutton addconstraint:[nslayoutconstraint constraintwithitem:cancelbutton                                                        attribute:nslayoutattributewidth                                                        relatedby:nslayoutrelationequal                                                           toitem:nil                                                        attribute:nslayoutattributenotanattribute                                                       multiplier:1.0                                                         constant:80]];  [cancelbutton addconstraint:[nslayoutconstraint constraintwithitem:cancelbutton                                                          attribute:nslayoutattributeheight                                                          relatedby:nslayoutrelationequal                                                             toitem:nil                                                          attribute:nslayoutattributenotanattribute                                                         multiplier:1.0                                                           constant:80]];