What to Know: 22 tricky tricks for iOS development

<span id="Label3"></p><p><p></p></p><p><p>Combined with their own practice development experience summed up the 22 iOS development tips, with a very happy tone to easily solve the development process encountered a variety of hardship problems, light reading has been laughing.</p></p><p><p><strong>1. What if the TableView does not display a cell with no content?</strong></p></p><p><p>Similar to Figure 1, I don't want to let those empty displays BELOW. Very simple, Add "self.tableView.tableFooterView = [[UIView alloc] init];" Try to say yes, after adding this sentence has become the Figure 2 Appearance.</p></p><p><p><strong>2. What do I do if I customize the Leftbarbuttonitem left slide return gesture to fail?</strong></p></p> <ol class="dp-j"> <ol class="dp-j"> <li class="alt">Self.navigationItem.leftBarButtonItem = [[uibarbuttonitem alloc]</li> <li>Initwithimage:img</li> <li class="alt">Style:uibarbuttonitemstyleplain</li> <li>Target:self</li> <li class="alt">Action:<span class="annotation">@selector (onback:)];</span></li> <li>Self.navigationController.interactivePopGestureRecognizer.delegate = (id<uigesturerecognizerdelegate>) Self ;</li> </ol> </ol><p><p><strong>3. ScrollView inexplicable can't viewcontroller to the top of the row?</strong></p></p> <ol class="dp-j"> <ol class="dp-j"> <li class="alt">Self.automaticallyadjustsscrollviewinsets = NO;</li> </ol> </ol><p><p><strong>4. Keyboard Event Write well irritable, all want to fall keyboard what to do?</strong></p></p><p><p>Buy a sturdy keyboard;<br>use iqkeyboardmanager (can be searched on github), The waist does not ache after use, the leg also is not sour.</p></p><p><p>5. Why my app is always not fluent, what is the problem?</p></p><p><p></p></p><p><p></p></p><p><p>This artifact is called: kmcgeigercounter, go to GitHub to carry it.</p></p><p><p>6. How to adjust the position of separaline without creating a new cell?</p></p> <ol class="dp-j"> <ol class="dp-j"> <li class="alt">_mytableview.separatorinset = Uiedgeinsetsmake (<span class="number">0, <span class="number">0, <span class="number"> <span class="number">0);</span> </span> </span> </span></li> </ol> </ol><p><p>7. How to click Self.view to let the keyboard, need to add a tapgestures?</p></p> <ol class="dp-j"> <ol class="dp-j"> <li class="alt">-(<span class="keyword">void) touchesbegan: (nsset *) touches withevent: (uievent *) event</span></li> <li>{</li> <li class="alt">[self.view endediting:yes];</li> <li>}</li> </ol> </ol><p><p><strong>8. How to set the default background image for each viewcontroller?</strong></p></p><p><p>Use the base class ah, Juvenile.</p></p><p><p><strong>9. Want to change in the code to add the Layoutattributes in the xib, but how to use the code to find?</strong></p></p><p><p>Pull the button like pull your restraint, Nslayoutattribute also can pull the Line.</p></p><p><p><strong>10. How to hide navigationbar when sliding like safari?</strong></p></p> <ol class="dp-j"> <ol class="dp-j"> <li class="alt">Navigationcontroller.hidesbarsonswipe = Yes</li> </ol> </ol><p><p><strong>11. Navigation bar Return key The title of the belt is too annoying, how to let it disappear?</strong></p></p> <ol class="dp-j"> <ol class="dp-j"> <li class="alt">[[uibarbuttonitem appearance] setbackbuttontitlepositionadjustment:uioffsetmake (<span class="number">0,-<span class="number">)</span> </span></li> <li>forbarmetrics:uibarmetricsdefault];</li> </ol> </ol><p><p><strong>CoreData used to be very annoying, grammar and smelly and long how to do?</strong></p></p><p><p>Magicrecord</p></p><p><p><strong>How does CollectionView implement Tableview's hover header?</strong></p></p><p><p>Csstickyheaderflowlayout</p></p><p><p><strong>14. Can I use only one pan gesture in place of the uiswipegesture in all directions?</strong></p></p> <ol class="dp-j"> <li class="alt"><li class="alt">-(<span class="keyword">void) pan: (uipangesturerecognizer *) Sender</span></li></li> <li><li>{</li></li> <li class="alt"><li class="alt">typedef ns_enum (nsuinteger, Uipangesturerecognizerdirection) {</li></li> <li><li>uipangesturerecognizerdirectionundefined,</li></li> <li class="alt"><li class="alt">uipangesturerecognizerdirectionup,</li></li> <li><li>uipangesturerecognizerdirectiondown,</li></li> <li class="alt"><li class="alt">uipangesturerecognizerdirectionleft,</li></li> <li><li>Uipangesturerecognizerdirectionright</li></li> <li class="alt"><li class="alt">};</li></li> <li><li><span class="keyword">static Uipangesturerecognizerdirection Direction = uipangesturerecognizerdirectionundefined;</span></li></li> <li class="alt"><li class="alt"><span class="keyword">Switch (sender.state) {</span></li></li> <li><li><span class="keyword">Case Uigesturerecognizerstatebegan: {</span></li></li> <li class="alt"><li class="alt"><span class="keyword">if (direction = = Uipangesturerecognizerdirectionundefined) {</span></li></li> <li><li>Cgpoint velocity = [sender velocityInView:recognizer.view];</li></li> <li class="alt"><li class="alt">BOOL isverticalgesture = fabs (velocity.y) > Fabs (velocity.x);</li></li> <li><li><span class="keyword">If (isverticalgesture) {</span></li></li> <li class="alt"><li class="alt"><span class="keyword">If (velocity.y > <span class="number">0) {</span></span></li></li> <li><li>Direction = uipangesturerecognizerdirectiondown;</li></li> <li class="alt"><li class="alt">} <span class="keyword">Else {</span></li></li> <li><li>Direction = uipangesturerecognizerdirectionup;</li></li> <li class="alt"><li class="alt">}</li></li> <li><li>}</li></li> <li class="alt"><li class="alt"><span class="keyword">else {</span></li></li> <li><li><span class="keyword">If (velocity.x > <span class="number">0) {</span></span></li></li> <li class="alt"><li class="alt">Direction = uipangesturerecognizerdirectionright;</li></li> <li><li>} <span class="keyword">Else {</span></li></li> <li class="alt"><li class="alt">Direction = uipangesturerecognizerdirectionleft;</li></li> <li><li>}</li></li> <li class="alt"><li class="alt">}</li></li> <li><li>}</li></li> <li class="alt"><li class="alt"><span class="keyword">Break</span></li></li> <li><li>}</li></li> <li class="alt"><li class="alt"><span class="keyword">Case Uigesturerecognizerstatechanged: {</span></li></li> <li><li><span class="keyword">Switch (direction) {</span></li></li> <li class="alt"><li class="alt"><span class="keyword">Case Uipangesturerecognizerdirectionup: {</span></li></li> <li><li>[self handleupwardsgesture:sender];</li></li> <li class="alt"><li class="alt"><span class="keyword">Break</span></li></li> <li><li>}</li></li> <li class="alt"><li class="alt"><span class="keyword">Case Uipangesturerecognizerdirectiondown: {</span></li></li> <li><li>[self handledownwardsgesture:sender];</li></li> <li class="alt"><li class="alt"><span class="keyword">Break</span></li></li> <li><li>}</li></li> <li class="alt"><li class="alt"><span class="keyword">Case Uipangesturerecognizerdirectionleft: {</span></li></li> <li><li>[self handleleftgesture:sender];</li></li> <li class="alt"><li class="alt"><span class="keyword">Break</span></li></li> <li><li>}</li></li> <li class="alt"><li class="alt"><span class="keyword">Case Uipangesturerecognizerdirectionright: {</span></li></li> <li><li>[self handlerightgesture:sender];</li></li> <li class="alt"><li class="alt"><span class="keyword">Break</span></li></li> <li><li>}</li></li> <li class="alt"><li class="alt"><span class="keyword">default: {</span></li></li> <li><li><span class="keyword">Break</span></li></li> <li class="alt"><li class="alt">}</li></li> <li><li>}</li></li> <li class="alt"><li class="alt"><span class="keyword">Break</span></li></li> <li><li>}</li></li> <li class="alt"><li class="alt"><span class="keyword">Case Uigesturerecognizerstateended: {</span></li></li> <li><li>Direction = uipangesturerecognizerdirectionundefined;</li></li> <li class="alt"><li class="alt"><span class="keyword">Break</span></li></li> <li><li>}</li></li> <li class="alt"><li class="alt"><span class="keyword">Default</span></li></li> <li><li><span class="keyword">Break</span></li></li> <li class="alt"><li class="alt">}</li></li> <li><li>}</li></li> </ol><p><p>15. How can I stretch the picture so that it doesn't deform?</p></p><p><p>Method One:</p></p> <ol class="dp-j"> <ol class="dp-j"> <li class="alt">UIImage *image = [[UIImage imagenamed:@<span class="string">"xxx"] stretchableimagewithleftcapwidth:<span class="number">topcapheight: ten<span class="number">];</span> </span></span></li> </ol> </ol><p><p>Note: developers are reminded that this has been deprecated, now the method is called Resizableimagewithcapinsets.</p></p><p><p><strong>Method two,</strong></p></p><p><p></p></p><p><p><strong>16. How to play gif when this card, there is no better library?</strong></p></p><p><p>Flipboard's Flanimatedimage is perfect for you.</p></p><p><p><strong>17. How to add a pull-up refresh in a sentence?</strong></p></p><p><p>Using the Svpulltorefresh library:</p></p> <ol class="dp-j"> <ol class="dp-j"> <li class="alt">[tableView addpulltorefreshwithactionhandler:^{</li> <li><span class="comment">prepend data to dataSource, insert cells at top of table view</span></li> <li class="alt"><span class="comment">Call [tableview.pulltorefreshview stopanimating] when done</span></li> <li>} position:svpulltorefreshpositionbottom];</li> </ol> </ol><p><p><strong>18. How do I change the color of the TableView cell to another color?</strong></p></p> <ol class="dp-j"> <ol class="dp-j"> <li class="alt">_mtableview.tintcolor = [uicolor redcolor];</li> </ol> </ol><p><p><strong>19. Originally my statusbar is lightcontent, The result uses Uiimagepickercontroller will cause my statusbar's style to turn black, how to do?</strong></p></p> <ol class="dp-j"> <ol class="dp-j"> <li class="alt">-(<span class="keyword">void) navigationcontroller: (uinavigationcontroller *) navigationcontroller willshowviewcontroller: ( Uiviewcontroller *) viewcontroller animated: (BOOL) animated</span></li> <li>{</li> <li class="alt">[[uiapplication sharedapplication] setstatusbarstyle:uistatusbarstylelightcontent];</li> <li>}</li> </ol> </ol><p><p><strong>20. How do I make my navigationbar transparent rather than blurry?</strong></p></p> <ol class="dp-j"> <ol class="dp-j"> <li class="alt">[self.navigationbar setbackgroundimage:[uiimage <span class="keyword">new]</span></li> <li>forbarmetrics:uibarmetricsdefault];</li> <li class="alt">Self.navigationBar.shadowImage = [UIImage <span class="keyword">new];</span></li> <li>Self.navigationBar.translucent = YES;</li> </ol> </ol><p><p><strong>21. How to change the color and position of Uitextfield placeholder?</strong></p></p><p><p>Inherit uitextfield, overriding this method:</p></p> <ol class="dp-j"> <ol class="dp-j"> <li class="alt">-(<span class="keyword">void) drawplaceholderinrect: (cgrect) rect {</span></li> <li>[[uicolor bluecolor] setfill];</li> <li class="alt">[self.placeholder drawinrect:rect WithFont:self.font linebreakmode:uilinebreakmodetailtruncation alignment: self.textalignment];</li> <li>}</li> </ol> </ol><p><p><strong>22. Why do you know so many strange tricks?</strong></p></p><p><p>Go stack Overflow brush problem ah, teenager!</p></p><p><p>What to Know: 22 tricky tricks for iOS development</p></p></span>