iOS Imitation Android gallery controls

No controls similar to Android Gallery have been found on iOS because they need to be used on the project. Implemented with Uicollectionview

Viewcontroller.m

#import "ViewController.h" #import "ImageCell.h" #import "LineLayout.h" @interface Viewcontroller () < Uicollectionviewdatasource, uicollectionviewdelegate> @property (nonatomic, strong) Nsmutablearray *images;@ Property (nonatomic, weak) Uicollectionview *collectionview; @end @implementation viewcontrollerstatic NSString *const                ID = @ "image";-(Nsmutablearray *) images{if (!_images) {self.images = [[Nsmutablearray alloc] init];        for (int i = 1; i<=20; i++) {[Self.images addobject:[nsstring stringwithformat:@ '%d ', I]]; }} return _images;}        -(void) viewdidload {[Super viewdidload];    CGFloat w = self.view.frame.size.width;    CGRect rect = CGRectMake (0, +, W, 200); Uicollectionview *collectionview = [[Uicollectionview alloc] Initwithframe:rect collectionviewlayout:[[linelayout    ALLOC] [init]];    Collectionview.datasource = self;    Collectionview.delegate = self; [CollectionView registernib:[uinib nibwithnibname:@ "imagecell "Bundle:nil] forcellwithreuseidentifier:id];    [Self.view Addsubview:collectionview];    Self.collectionview = CollectionView; Collectionviewlayout://Uicollectionviewlayout//uicollectionviewflowlayout}-(void) Touchesbegan: (NSSet *) Touc        Hes withevent: (uievent *) event{if ([Self.collectionView.collectionViewLayout Iskindofclass:[linelayout class]]) {    [Self.collectionview Setcollectionviewlayout:[[uicollectionviewflowlayout alloc] init] animated:yes];    } else {[Self.collectionview setcollectionviewlayout:[[linelayout alloc] init] animated:yes]; }} #pragma mark-<uicollectionviewdatasource>-(Nsinteger) CollectionView: (Uicollectionview *) CollectionView Numberofitemsinsection: (Nsinteger) section{return self.images.count;} -(Uicollectionviewcell *) CollectionView: (Uicollectionview *) CollectionView Cellforitematindexpath: (NSIndexPath *) indexpath{Imagecell *cell = [CollectionView dequeuereusablecellwithreuseidentifier:id ForIndexPath:indexPATH];    Cell.image = Self.images[indexpath.item]; return cell;} -(void) CollectionView: (Uicollectionview *) CollectionView Didselectitematindexpath: (Nsindexpath *) indexPath{//        Delete model data [self.images RemoveObjectAtIndex:indexPath.item]; Delete ui (Refresh UI) [CollectionView Deleteitemsatindexpaths:@[indexpath];} @end

Linelayout.m

#import "LineLayout.h" static const cgfloat ITEMWH =, @implementation linelayout-(instancetype) init{if (self = [sup ER init]) {} return self;} /** * re-layout as long as the displayed boundary changes: Internally the Preparelayout and Layoutattributesforelementsinrect methods are called back to get the layout properties of all cells */-(BOOL) Shouldinvalidatelayoutforboundschange: (cgrect) newbounds{return YES;}              /** * Used to set CollectionView stop scrolling at that moment of position * * @param proposedcontentoffset originally CollectionView stop scrolling at that moment of position * @param velocity Scrolling speed */-(cgpoint) Targetcontentoffsetforproposedcontentoffset: (cgpoint) Proposedcontentoffset    Withscrollingvelocity: (cgpoint) velocity{//1. Calculate the range of ScrollView last stop CGRect lastrect;    Lastrect.origin = Proposedcontentoffset;        Lastrect.size = self.collectionView.frame.size;        Calculate the center of the screen x cgfloat CenterX = proposedcontentoffset.x + self.collectionView.frame.size.width * 0.5;        2. Remove all properties within this range nsarray *array = [self layoutattributesforelementsinrect:lastrect]; 3. Traverse All properties CGFloat adjustoffsetx = MaxfloaT  For (uicollectionviewlayoutattributes *attrs in array) {if (ABS (Attrs.center.x-centerx) < ABS (ADJUSTOFFSETX))        {adjustoffsetx = Attrs.center.x-centerx; }} return Cgpointmake (Proposedcontentoffset.x + adjustoffsetx, proposedcontentoffset.y);}         /** * Some of the initialization work is best implemented here */-(void) preparelayout{[Super Preparelayout];    The size of each cell self.itemsize = Cgsizemake (Itemwh, ITEMWH);    CGFloat inset = (SELF.COLLECTIONVIEW.FRAME.SIZE.WIDTH-HMITEMWH) * 0.5;    Self.sectioninset = Uiedgeinsetsmake (0, inset, 0, inset);    Set Horizontal scrolling self.scrolldirection = uicollectionviewscrolldirectionhorizontal;        self.minimumlinespacing = Itemwh * 0.7; Each cell (item) has its own uicollectionviewlayoutattributes//each indexpath has its own uicollectionviewlayoutattributes}/** Effective Distance: When the middle X of item is within hmactivedistance of the middle X of the screen, it will only start to zoom in, and all other cases are reduced */static cgfloat const Activedistance = 150;/** Scaling factor: The higher the value, Item will be larger */static cgfloat const Scalefactor = 0.6;-(Nsarray *) LayoUtattributesforelementsinrect: (CGRect) rect{//0. Calculate the visible rectangle box CGRect visiablerect;    Visiablerect.size = self.collectionView.frame.size;        Visiablerect.origin = Self.collectionView.contentOffset;    1. Obtain the default cell's uicollectionviewlayoutattributes nsarray *array = [Super Layoutattributesforelementsinrect:rect];        Calculate the center of the screen x cgfloat CenterX = self.collectionview.contentoffset.x + self.collectionView.frame.size.width * 0.5; 2. Traverse all layout properties for (uicollectionviewlayoutattributes *attrs in array) {//If not on the screen, skip directly if (!                Cgrectintersectsrect (Visiablerect, attrs.frame)) continue;                The midpoint of each item x cgfloat Itemcenterx = attrs.center.x; The smaller the gap, the larger the scaling ratio cgfloat scale = 1 + scalefactor * (1-(ABS (Itemcenterx-centerx)/Ac) based on the distance to the center of the screen        Tivedistance));    Attrs.transform = Cgaffinetransformmakescale (scale, scale); } return array; @end

imagecell.m

#import "ImageCell.h" @interface Imagecell () @property (weak, nonatomic) Iboutlet Uiimageview *imageview;@ End@implementation imagecell-(void) awakefromnib {    self.imageView.layer.borderWidth = 3;    Self.imageView.layer.borderColor = [Uicolor Whitecolor]. Cgcolor;    Self.imageView.layer.cornerRadius = 3;    Self.imageView.clipsToBounds = YES;} -(void) SetImage: (NSString *) image{    _image = [image copy];        Self.imageView.image = [UIImage imagenamed:image];} @end

iOS Imitation Android gallery controls