iOS Development UI Chapter-uiscrollview control implements picture Carousel

iOS Development UI Chapter-uiscrollview control implements picture Carousel

First, the realization effect

Auto-Carousel for images

Second, the implementation of the Code

Layout in Storyboard

Code:

 1 #import "TXViewController.h"  2   3 @interfaceTxviewcontroller () <UIScrollViewDelegate>4@property (Weak, nonatomic) Iboutlet Uiscrollview *ScrollView; 5 /** 6 * Page 7*/  8@property (Weak, nonatomic) Iboutlet Uipagecontrol *Pagecontrol; 9  Ten@property (nonatomic, strong) Nstimer *timer; One @end  A   - @implementationTxviewcontroller -   the- (void) Viewdidload - {  -[Super Viewdidload]; -       + //the width of the picture  -CGFloat Imagew =Self.scrollview.frame.size.width; + //cgfloat Imagew = +;  A //Picture High  atCGFloat Imageh =Self.scrollview.frame.size.height; - //the y of the picture  -CGFloat Imagey =0;  - //Number of pictures  -Nsinteger TotalCount =5;  - //1. Add 5 photos  in      for(inti =0; i < TotalCount; i++) {  -Uiimageview *imageview =[[Uiimageview alloc] init]; to //picture x  +CGFloat ImageX = i *Imagew; - //Set Frame  theImageview.frame =CGRectMake (ImageX, Imagey, Imagew, Imageh); * //set up a picture  $NSString *name = [NSString stringWithFormat:@"img_0%d", i +1]; Panax NotoginsengImageview.image =[UIImage imagenamed:name]; - //Hide the indicator bar  theSelf.scrollview.showsHorizontalScrollIndicator =NO; +           A[Self.scrollview Addsubview:imageview]; the     }  +       - //2. Set the scroll range of the ScrollView  $CGFloat CONTENTW = TotalCount *Imagew; $     //do not allow scrolling in the vertical direction  -Self.scrollview.contentSize = Cgsizemake (CONTENTW,0);  -       the //3. Set Paging  -self.scrollview.pagingEnabled =YES;Wuyi       the //4. Monitor the scrolling of ScrollView  -Self.scrollview.Delegate=Self ; Wu       -[self addtimer]; About }  $   -- (void) NextImage - {  -     intpage = (int) Self.pageControl.currentPage;  A     if(page = =4) {  +page =0;  the}Else  -     {  $page++;  the     }  the       the //scrolling ScrollView  theCGFloat x = page *Self.scrollview.frame.size.width; -Self.scrollview.contentOffset = Cgpointmake (x,0);  in }  the   the //ScrollView when scrolling is called  About- (void) Scrollviewdidscroll: (Uiscrollview *) ScrollView the {  theNSLog (@"Scrolling in");  the //Calculate page Numbers  + //page number = (Contentoffset.x + scrollview half width)/scrollview width  -CGFloat SCROLLVIEWW =ScrollView.frame.size.width; theCGFloat x =Scrollview.contentoffset.x;Bayi     intpage = (x + scrollvieww/2) /Scrollvieww; theSelf.pageControl.currentPage =page; the }  -   - //call when dragging is started  the- (void) Scrollviewwillbegindragging: (Uiscrollview *) ScrollView the {  the //Turn off the timer (note: Once the timer is closed, it can no longer be turned on)  the //[Self.timer invalidate];  -[self removetimer]; the }  the   the- (void) Scrollviewdidenddragging: (Uiscrollview *) ScrollView willdecelerate: (BOOL) decelerate94 {  the //Turn on Timer  the[self addtimer]; the } 98   About /**100 * Turn on Timer 101*/102- (void) addtimer{103     104Self.timer = [Nstimer scheduledtimerwithtimeinterval:1target:self selector: @selector (nextimage) Userinfo:nil Repeats:yes]; the[[Nsrunloop Currentrunloop] AddTimer:self.timer formode:nsrunloopcommonmodes];106 }107 /**108 * off timer 109*/ the- (void) Removetimer111 { the[Self.timer invalidate];113 } the @end

Tip: The following two properties have been wired to the controls in storyboard.

@property (Weak, nonatomic) Iboutletuiscrollview *scrollview;

@property (Weak, nonatomic) Iboutletuipagecontrol *pagecontrol;

Supplement: Timer Nstimer

Timers are designed to be used at intervals of time to do some long-spaced operations.

Nstimeinterval: How long and how many pieces to operate once

Target: Who to manipulate

Selector: The method to be manipulated

UserInfo: Passing Parameters

Repeats: whether to repeat

Self.timer = [Nstimer scheduledtimerwithtimeinterval:1 target:self selector: @selector (nextimage) Userinfo:nil repeats : YES];

iOS Development UI Chapter-uiscrollview control implements picture Carousel