Ios-uicollectionviewcontroller protocol and callbacks

I. Uicollectionviewdatasource

1. Ways to return the number of sections

-(Nsinteger) Numberofsectionsincollectionview: (Uicollectionview *) CollectionView {    return 5 ;}

2. Methods to return the number of cells in each section

-(Nsinteger) CollectionView: (Uicollectionview *) CollectionView     numberofitemsinsection: (NSInteger) Section {    return;}

3. Select the cell used in the CollectionView

-(Uicollectionviewcell *) CollectionView: (Uicollectionview *) CollectionView                  *) Indexpath {         // using the cell reuse identifier to get cell    Collectionviewcell *cell = [CollectionView Dequeuereusablecellwithreuseidentifier:reuseidentifier                                                                         Forindexpath:indexpath];        return cell;}

4. How to register Uicollectionreusableview.

uinib *headernib = [uinib nibwithnibname:@"Collectionheaderreusableview"bundle: [NSBundle Mainbundle]]; //Register to Reuse view[Self.collectionview registernib:headernib Forsupplementaryviewofkind:uicollectionelementkindsectionhea Der Withreuseidentifier:@"Collectionheaderreusableview"]; //Register Footerviewuinib *footernib = [uinib nibwithnibname:@"Collectionfooterreusableview"bundle:[NSBundle Mainbundle]];                 [Self.collectionview registernib:footernib Forsupplementaryviewofkind:uicollectionelementkindsectionfooter Withreuseidentifier:@"Collectionfooterreusableview"];

5. Settings in Uicollectionviewdatasource supplementary View

-(Uicollectionreusableview *) CollectionView: (Uicollectionview *) CollectionView viewforsupplementaryelementofkind: (NSString*) Kind Atindexpath: (Nsindexpath*) indexpath{//Set Sectionheader    if([Kind Isequaltostring:uicollectionelementkindsectionheader]) {Uicollectionreusableview*view = [CollectionView dequeuereusablesupplementaryviewofkind:uicollectionelementkindsectionheader Withreuseidentifier:@"Collectionheaderreusableview"Forindexpath:indexpath]; returnview; }        //Set SectionfooterUicollectionreusableview *view = [CollectionView dequeuereusablesupplementaryviewofkind: Uicollectionelementkindsectionfooter Withreuseidentifier:@"Collectionfooterreusableview"Forindexpath:indexpath]; returnview; }

Two. Uicollectionviewdelegateflowlayout

1.Cell Custom Size

-(Cgsize) CollectionView: (Uicollectionview *) CollectionView                  layout: (uicollectionviewlayout*) Collectionviewlayout  *) indexpath{        if0) {        return Cgsizemake ();    }         return Cgsizemake ();}

2. Change the upper and lower left and Right margins of section--uiedgeinsetsmake

-(Uiedgeinsets) CollectionView: (Uicollectionview *) CollectionView                        layout: (uicollectionviewlayout* ) collectionviewlayout        insetforsectionatindex: (nsinteger) section{        if0) {         return Uiedgeinsetsmake ()    ;     return Uiedgeinsetsmake (0000);}

3. The upper and lower margins of each cell

-(CGFloat) CollectionView: (Uicollectionview *) CollectionView                   layout: (uicollectionviewlayout*) Collectionviewlayoutminimumlinespacingforsectionatindex: (nsinteger) section{    if0  ) {        return5.0f;    }     return 20.0f ;}

4. Set the left and right margins of the cell

-(CGFloat) CollectionView: (Uicollectionview *) CollectionView                   layout: (uicollectionviewlayout*) Collectionviewlayoutminimuminteritemspacingforsectionatindex: (nsinteger) section{    if0  ) {        return5.0f;    }     return 20.0f ;}

5. Set the size of the header view and footer view

-(Cgsize) CollectionView: (Uicollectionview *) CollectionView                  layout: (uicollectionviewlayout*) Collectionviewlayoutreferencesizeforheaderinsection: (nsinteger) section{    return cgsizemake (  $  - );} -(Cgsize) CollectionView: (Uicollectionview *) CollectionView                  layout: (uicollectionviewlayout*) Collectionviewlayoutreferencesizeforfooterinsection: (nsinteger) section{    return cgsizemake (a);}

Three. Uicollectionviewdelegate

1. Set cell to highlight

-(BOOL) CollectionView: (Uicollectionview **) indexpath{        return  YES;    }

The following method is called back when the 2.Cell has changed from non-highlight to highlight and from highlight to non-highlighted state

-(void) CollectionView: (Uicollectionview **) indexpath{        [self Changehighlightcellwithindexpath:indexpath];} -(void) CollectionView: (Uicollectionview **) indexpath{        [self Changehighlightcellwithindexpath:indexpath];}

3. Set whether the cell is optional

-(BOOL) CollectionView: (Uicollectionview *) CollectionView Shouldselectitematindexpath: (Nsindexpath *) IndexPath {    return  YES;}

4.Cell Support Multi-Select

Self.collectionView.allowsMultipleSelection = YES;

5. Need to support canceling cell multiple selection in multi-select mode

-(BOOL) CollectionView: (Uicollectionview *) CollectionView Shoulddeselectitematindexpath: (Nsindexpath *) indexpath{    return  YES;

6.Cell will appear, after the cell appears,Supplementary view will appear and supplementary view has appeared

/** * Call this method when the cell is about to appear*/- (void) CollectionView: (Uicollectionview *) CollectionView Willdisplaycell: (Uicollectionviewcell *) cell ForItemAtIndexPath :(Nsindexpath *) Indexpath Ns_available_ios (8_0) {NSLog (@"the%ld cell on the first%ld section will appear", Indexpath.section, Indexpath.row);}/** * Call this method after the cell appears*/- (void) CollectionView: (Uicollectionview *) CollectionView Didenddisplayingcell: (Uicollectionviewcell *) cell Foritematindexpath: (Nsindexpath *) indexpath{NSLog (@"the%ld cell on section%ld has already appeared", Indexpath.section, Indexpath.row);}/** * Headerview or Footerview will appear when the method is called*/- (void) CollectionView: (Uicollectionview *) CollectionView Willdisplaysupplementaryview: (Uicollectionreusableview *) view Forelementkind: (NSString *) elementkind Atindexpath: (Nsindexpath *) Indexpath Ns_available_ios (8_0) {NSLog (@"the%ld extension view on the first%ld section will appear", Indexpath.section, Indexpath.row); }/** * Headerview or Footerview occurs after the method is called*/- (void) CollectionView: (Uicollectionview *) CollectionView Didenddisplayingsupplementaryview: (UICollectionReusableView *) View Forelementofkind: (NSString *) elementkind Atindexpath: (Nsindexpath *) indexpath{NSLog (@"The first%ld extension view on section%ld has already appeared", Indexpath.section, Indexpath.row); }

Ios-uicollectionviewcontroller protocol and callbacks