When will IOS layoutsubviews be called?

<span id="Label3"></p><p><p><span style="font-size: 14px;"><span style="font-family: Comic Sans MS;">Original: when does layoutsubviews get called?</span></span></p></p><p><p></p></p><p><p><span style="font-family: ‘Courier New‘;"><span style="font-size: 14px;">It ' s important to optimize any UIView Layoutsubviews method you create, as it can be frequently called, and have the potent Ial for creating recursion (triggering a setneedslayout from Layoutsubviews can create a loop that'll grossly affect you R Apps performance). <span style="color: #ff0000;">Layout Subviews is called once per run loop on any view this has had setneedslayout or Setneedsdisplaywithrect:calle D on it. So-in Addition-to-any-time Manually call these methods, it can is useful to know when the UI framework calls SETNEEDSL Ayout/setneedsdisplay as this would trigger Layoutsubviews.</span></span></span></p></p><p><p></p></p><p><p><span style="font-family: ‘Courier New‘;"><span style="font-size: 14px;"><br></span></span></p></p><p><p></p></p><p><p><span style="font-family: ‘Courier New‘;"><span style="font-size: 14px;">。 Init does not cause layoutsubviews to be called (duh)</span></span></p></p><p><p></p></p><p><p><span style="font-size: 14px;"><span style="font-family: Comic Sans MS;">Layoutsubviews is not called when initializing</span></span></p></p><p><p></p></p><p><p><span style="font-family: ‘Courier New‘;"><span style="font-size: 14px;">。 Addsubview causes Layoutsubviews to being called on the view being added, the view it's being added to (target view), and all The subviews of the target view</span></span></p></p><p><p></p></p><p><p><span style="font-size: 14px;"><span style="font-family: Comic Sans MS;">[view addsubview:subview] causes all child view View,subview and view to be called Layoutsubviews</span></span></p></p><p><p></p></p><p><p><span style="font-family: ‘Courier New‘;"><span style="font-size: 14px;">。 Setframe intelligently calls Layoutsubviews on the view have it ' s frame set only if the size parameter of the frame is D Ifferent</span></span></p></p><p><p></p></p><p><p><span style="font-size: 14px;"><span style="font-family: Comic Sans MS;">setframe, The layoutsubviews is called when the Frame's Frame.size is changed and the size is changed before and after the change, Frame.origin will not be called layoutsubviews</span></span></p></p><p><p></p></p><p><p><span style="font-family: ‘Courier New‘;"><span style="font-size: 14px;">。 Scrolling a uiscrollview causes Layoutsubviews to being called on the scrollView, and it ' s Superview</span></span></p></p><p><p></p></p><p><p><span style="font-size: 14px;"><span style="font-family: Comic Sans MS;">Sliding Uiscrollview causes the ScrollView and its parent view to be called Layoutsubviews</span></span></p></p><p><p></p></p><p><p><span style="font-family: ‘Courier New‘;"><span style="font-size: 14px;">。 Rotating a device only calls Layoutsubview on the parent view (the responding Viewcontrollers primary view)</span></span></p></p><p><p></p></p><p><p><span style="font-size: 14px;"><span style="font-family: Comic Sans MS;">Rotating the device only causes the parent view to call Layoutsubviews</span></span></p></p><p><p></p></p><p><p><span style="font-family: ‘Courier New‘;"><span style="font-size: 14px;">。 Removefromsuperview–layoutsubviews is called on Superview only</span></span></p></p><p><p></p></p><p><p><span style="font-size: 14px;"><span style="font-family: Comic Sans MS;">Removefromsuperview will only be the parent view call Layoutsubviews</span></span></p></p><p><p></p></p><p><p><span style="font-family: ‘Courier New‘;"><span style="font-size: 14px;"><br></span></span></p></p><p><p></p></p><p><p><span style="font-size: 14px;"><span style="font-family: Comic Sans MS;">Suggest you look at the original text, above is just excerpts</span></span></p></p><p><p></p></p><p><p>When will IOS layoutsubviews be called?</p></p></span>