ios - Inserting the first cell into a collection view causes an assertion failure -


if try insert item uicollectionview when there 0 sections , 0 items, assertion failure.

*** terminating app due uncaught exception 'nsinternalinconsistencyexception', reason: 'invalid update: invalid number of sections. number of sections contained in collection view after update (1) must equal number of sections contained in collection view before update (0), plus or minus number of sections inserted or deleted (0 inserted, 0 deleted).'

a classic. problem is, i'm modifying data source , inserting item directly afterwards. showfirstcell property checked in of necessary data source methods , isn't modified anywhere else.

self.showfirstcell = true self.collectionview.insertitemsatindexpaths([nsindexpath(foritem: 0, insection: 0)])

wrapping in performbatchupdates changes nothing.

i item added in animated fashion. don't think should have first check if there items in place, doing , calling reloaddata instead work, it's not perfect.

your number of sections don't match up.

once have decided enter section uicollectionview, should return same number in numberofsections function well.

what's happening right insert cell, , calls numberofsections function again, still returning 0, , promptly crashes.


Comments

Post a Comment

Popular posts from this blog

cakephp - simple blog with croogo -

i not problem, made simple blog in croogo, problem is not adding or modifying or delete, because arabic language ?? function add in controller `public function admin_add() { $this->set('title_for_layout', __('add part')); if (!empty($this->request->data)) { $this->part->create(); if ($this->part->save($this->request->data)) { $this->session->setflash(__('the part has been saved'), 'default', array('class' => 'success')); $this->redirect(array('action' => 'index'));//, $this->part->id)); } else { $this->session->setflash(__('the part not saved. please, try again.'), 'default', array('class' => 'error')); } } }` => model `class part extends appmodel { public $name = 'part'; var $belongst...
Read more

How to group boxplot outliers in gnuplot -

i have large set of data points. try plot them boxplot, of outliers exact same value , represented on line beside each other. found how set horizontal distance between outliers in gnuplot boxplot , doesn't much, apparently not possible. is possible group outliers together, print 1 point , print number in brackets beside indicate how many points there are? think make more readable in graph. for information, have 3 boxplots 1 x value , times 6 in 1 graph. using gnuplot 5 , played around pointsize, doesn't reduce distance anymore. hope can help! edit: set terminal pdf set output 'dat.pdf' file0 = 'dat1.dat' file1 = 'dat2.dat' file2 = 'dat3.dat' set pointsize 0.2 set notitle set xlabel 'x' set ylabel 'y' header = system('head -1 '.file0); n = words(header) set xtics ('' 1) set [i=1:n] xtics add (word(header, i) i) set style data boxplot plot file0 using (1-0.25):1:(0.2) boxplot lw 2 lc rgb '#8b0000...
Read more

bash - Performing variable substitution in a string -

i have string contains use of variable, , i'd substitute variable's value string. right best have is #!/bin/bash foo='$name; echo bar' name="the name" expanded="$(eval echo "$foo")" echo "$expanded" which has obvious defects: prints the name bar while i'd print the name; echo bar instead of eval can bash's regex matching bash's string replacement: foo='$name; echo bar' name="the name" [[ "$foo" =~ \$([[:alnum:]]+) ]] && s="${!bash_rematch[1]}" && expanded="${foo/\$${bash_rematch[1]}/$s}" echo "$expanded" name; echo bar
Read more