ios - Is it ok to keep multiple child view controllers associated with a parent UIViewController even when their views are not visible? -


scenario: have set of objects. wish display them using uitableview when device in portrait mode, , in uicollectionview when in landscape. accomplish this, want use uiviewcontroller container, , give 2 child view controllers (one each uicollectionviewcontroller , uitableviewcontroller). expect orientation change often, resulting in parent swapping , forth between 2 child controllers.

in view controller programming guide ios (2012-12-13), on pages 117 , 118 talking transitions between children, remove child view controller parent whenever child's view removed view hierarchy. (see listing 14-3 in particular.)

is necessary memory or whatever other reasons, or ok keep both child view controllers associated parent, , flip , forth between views? there performance advantages either technique?

there no problem having both view controllers children, need ensure appropriate resources either shared between them (i.e. don't have 2 copies of objects display) or released when views shown , hidden.

in case, 2 view controllers displaying same data, assume when switch between 2 update scrolled position based on happened in other view. if case there isn't lot of benefit keeping other view controller allocated , child. thing save allocated cells cached inside view. memory efficient should remove view controller isn't on display. costs little more @ runtime should not noticeable.


Comments

Post a Comment

Popular posts from this blog

SPSS keyboard combination alters encoding -

my question not have programming practical issue on spss. accident keyword combination cannot remember because did not intend press changed encoding in spss , text in data in different language english shown small boxes. nevertheless, when kind of analysis performed different language text shown in output. does know reason? tried change encoding did not produce result. first, @ edit > options , see whether setting unicode or locale. might fix it. if have text in multiple languages, want unicode. otherwise, may have specific locale set wrong. can change set locale, need know locale want use.
Read more

Add new record to the table by click on the button in Microsoft Access -

in ms access form want implement separate button, adds new record table. in order added button , attached button event: private sub btnaddrec_click() refresh codecontextobject on error resume next docmd.gotorecord , , acnewrec if err.number <> 0 btnaddrec.enabled = false end if end end sub everything ok when open window , click btnaddrec button, problem when first of perform navigation through existed records , after click on button. got runtime error: 2105: «you can't go specified record. may @ end of recordset» . how solve issue, need have ability add new record on click on specific button, no matter, have walked or not walked through records before. thanks. i created simple form field call description (and autonumber) , created button code follows click event. filled number of records , navigated through them, clicked addnewrec button. form navigated new record without issues. able click addnewrec button directly after
Read more

CSS3 Transition to highlight new elements created in JQuery -

i want use css3 color transition apply highlight-fading color effect (yellow transparent) new elements appended markup using jquery. css #content div { background-color:transparent; -moz-transition:background-color 2s; -webkit-transition:background-color 2s; -o-transition:background-color 2s; transition:background-color 2s; } #content div.new { background-color:yellow; } html <div id="content"></div> <a id="add-element" href="#">add new element</a> js $('#add-element').click(function() { var newelement = $('<div class="new">new element</div>'); $('#content').append(newelement); newelement.removeclass('new'); }); when click link, new element created. class "new" (background color yellow) , it's appended html markup. should able remove "new" class trigger background color transition transparent (or whate
Read more