Uiscrollview and Uipagecontrol implement app launch slide diagram

First, the use of nsuserdefaults to determine whether the slide diagram has occurred, loading slide diagram

Nsuserdefaults Introduction:

       nsuserdefaults can add data permanent save in the phone, he is a singleton, easy to use, So well suited for save simple data and for Data do tag

  you can choose to APPDELEGATE.M didfinishlaunch "); Ingwithoptions method or "initial interface "(Load the first viewcontroller) of   viewdidload method to determine if the slide diagram has occurred, write the code:

Nsuserdefaults *userdefaults = [Nsuserdefaults standarduserdefaults];//determine if the slide graph has occurred, the first call "Isscrollviewappear" this key The corresponding value is nil, which enters if if (![    @ "YES" isequaltostring:[userdefaults objectforkey:@ "Isscrollviewappear"]) {[Self showscrollview];//show slide chart }

Second, initialize Uiscrollview and Uipagecontrol to prepare for the page slide diagram.

Uiscrollview : With sliding effect, after adding Uiimageview to set up the agent , you can realize the effect of page flipping display picture

Related properties involved:

Contentsize: uiscrollview display size, this is based on demand

Pagingenabled: Whether to support a page-by-page turn, set to Yes, each time sliding, flipping a page;

Bounces: Whether support rebound, this is an animation effect, you can set to see, General slide chart set to No;

Showshorizontalscrollindicator: Whether to show the horizontal slide bar

Uipagecontrol : Commonly used in conjunction with Uiscrollview, pointing to the number of pages that Uiscrollview currently refers to

Related properties involved:

Numberofpages: There are a few points (several pages), this to be set to the same number of pages of the slide graph

Related code:

#pragma  mark -  slide diagram-(void)  showscrollview{    uiscrollview *_ scrollview = [[uiscrollview alloc] initwithframe:[uiscreen mainscreen].bounds];           //set the size of the display content of uiscrollview , there are n graphs to display, set   screen width *n &NBSP, this assumes that you want to display 4 images     _scrollview.contentsize = cgsizemake ([UIScreen  Mainscreen].bounds.size.width * 4, [uiscreen mainscreen].bounds.size.height);         _scrollView.tag = 101;         //Set page flipping effect, do not allow bounce, do not show horizontal slider, set proxy for yourself     _scrollView.pagingEnabled = YES;     _scrollview.bounces = no;    _ scrollview.showshorizontalscrollindicator = no;    _scrollview.delegate =  self;        //Join  UIImageView    for  on uiscrollview  (int i = 0 ;  i < 4; i ++)  {                 UIImageView *imageView = [[UIImageView alloc]  Initwithframe:cgrectmake ([uiscreen mainscreen].bounds.size.width * i , 0, [ Uiscreen mainscreen].bounds.size.width, [uiscreen mainscreen].bounds.size.height)];                 //the picture that will be loaded into imageview  Zhong         uiimage *image = [uiimage imagenamed:[ nsstring stringwithformat:@ "%d", i+1]];        imageview.image  = image;                 [_scrollview addsubview:imageview];    }        //Initialize  uipagecontrol   and  _scrollView  display in   same page     uipagecontrol *pageconteol =  [[uipagecontrol alloc] initwithframe:cgrectmake (140, self.view.frame.size.height - &NBSP;60,&NBSP;50,&NBSP;40)];    pageconteol.numberofpages = 4;//Settings PageConteol   page  as much as the  _scrollView  pictures     pageConteol.tag = 201;         [self.view addsubview:_scrollview];    [ Self.view addsubview: pageconteol];}

Third, the implementation of Uiscrollview agent method

-(void) scrollviewdidenddecelerating: (uiscrollview *) ScrollView Introduction:

As the name implies, this is a method of sliding the end of deceleration, where the uipagecontrol and uiscrollview

The use of the set, slide diagram disappears information, etc.:

Related properties are involved:

Uiscrollview:

Contentoffset: offset of uiscrollview (sliding position)

Uipagecontrol:

CurrentPage: Current page of Uipagecontrol

Related code:

#pragma  mark - UIScrollViewDelegate-  (void) scrollviewdidenddecelerating: (Uiscrollview  *) scrollview{        //  record the current position of the scrollview  because the paging effect has been set , so: location/Screen size  =  page     int current = scrollview.contentoffset.x/[ uiscreen mainscreen].bounds.size.width;        //according to ScrollView The   position is assigned to the current page of page      UIPageControl *page =  (uipagecontrol *) [ self.view viewwithtag:201];    page.currentpage = current;         //when the last page is displayed, let the slide graph disappear     if  (page.currentpage = = 3)  {                 //call method to make the slide graph disappear         [self scrollViewDisappear];     }}

Iv. removing uiscrollview from the screen, and save the information

uiscrollview and remove and do not forget and of course you can set some animation effects , or you need to click to remove it, the code given below is a simple animation effect:

code as follows:

-(void) scrollviewdisappear{    //get  view   UIScrollView  and   uipagecontrol    uiscrollview *scrollview =  (UIScrollView *) [Self.view  viewWithTag:101];    UIPageControl *page =  (uipagecontrol *) [ self.view viewwithtag:201];    //set the slide chart to disappear animation     [UIView  animatewithduration:3.0f animations:^{                 scrollview.center = cgpointmake (self.view.frame.size.width/2, 1.5  * self.view.frame.size.height);             } completion:^ (bool finished)  {                 [scrollView removeFromSuperview];         [page removefromsuperview];    }];        //to save the slide graph's start-up information to  NSUserDefaults  so that the second time do not run the slide diagram     nsuserdefaults *userdefaults = [ nsuserdefaults standarduserdefaults];    [userdefaults setobject:@ "YES"   forkey:@ "Isscrollviewappear"];}

This slide diagram code changes slightly, you can add the timing page, album browsing, click Connect to the corresponding event, etc., the principle is the same.