仿写了一个类似微信选择添加图片的demo，非常容易添加到工程当中，github地址https://github.com/wubianxiaoxian/AddPicture，主要用到了collectionview

1 //  2 //  ViewController.m  3 //  KevinCollectionView  4 //  5 //  Created by Kevin Sun on 15/12/14.  6 //  Copyright © 2015年 Kevin Sun. All rights reserved.  7 //  8   9 #import "ViewController.h" 10 #import "CollectionViewCell.h" 11 #import "KevinPreViewController.h" 12  13 static NSMutableArray *currentImages; 14  15 @interface ViewController ()
     
      { 16     UICollectionView *_collectionView; 17      18 } 19  20  21 @end 22  23 @implementation ViewController 24 - (void)viewDidLoad { 25     [super viewDidLoad]; 26     self.view.backgroundColor=[UIColor whiteColor]; 27     UICollectionViewFlowLayout *layout=[[UICollectionViewFlowLayout alloc]init]; 28     layout.minimumLineSpacing = 0.0f; 29     layout.minimumInteritemSpacing = 0.0f; 30  31     _collectionView=[[UICollectionView alloc]initWithFrame:self.view.frame collectionViewLayout:layout]; 32 //    [_collectionView mas_makeConstraints:^(MASConstraintMaker *make) { 33 //        make.left.right.top.bottom.mas_equalTo(0); 34 //    }]; 35     self.navigationController.navigationBar.barTintColor=[UIColor clearColor]; 36  37     [self.view addSubview:_collectionView]; 38     _collectionView.backgroundColor=[UIColor whiteColor]; 39     _collectionView.delegate=self; 40     _collectionView.dataSource=self; 41     [_collectionView registerNib:[UINib nibWithNibName:@"CollectionViewCell" bundle:nil] forCellWithReuseIdentifier:@"CellIdentifier"]; 42     if(currentImages ==nil) 43     { 44         currentImages=[[NSMutableArray alloc] init]; 45     } 46  47      48      49     // Do any additional setup after loading the view, typically from a nib. 50 } 51 -(void)viewWillAppear:(BOOL)animated{ 52     [_collectionView reloadData]; 53 } 54 #pragma mark -UIColletionDelegate 55 //指定setion个数 56 -(NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView{ 57     return 1; 58 } 59 //指定section中的colletionviewCELL的个数 60 -(NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section{ 61     return currentImages.count==0?1:currentImages.count+1; 62 } 63 //配置section中的collectionviewcell的展示 64 -(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{ 65     CollectionViewCell *cell=[collectionView dequeueReusableCellWithReuseIdentifier:@"CellIdentifier" forIndexPath:indexPath]; 66 //    cell.backgroundColor=[UIColor redColor]; 67      68     UIImageView *imageView=[[UIImageView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width/4-10, self.view.frame.size.width/4-10)]; 69     NSLog(@"currentImages.count %ld",currentImages.count); 70     for(UIView *view in [cell.contentView subviews]) 71     { 72         [view removeFromSuperview]; 73     } 74     if(currentImages.count==0||indexPath.row==currentImages.count) 75     {          NSLog(@"我加载了设置加好图片"); 76         imageView.image=nil; 77 //        [cell.contentView removeFromSuperview:imageView]; 78         imageView.image=[UIImage imageNamed:@"ico.ooopic.com.png"]; 79     } 80     else{ 81         NSLog(@"我加载了设置背景图片"); 82          83         while ([cell.contentView.subviews lastObject] != nil) { 84             [(UIView*)[cell.contentView.subviews lastObject] removeFromSuperview]; 85         } 86         imageView.image=currentImages[indexPath.row]; 87     } 88      89 //    imageView.contentMode=UIViewContentModeScaleAspectFill; 90     [cell.contentView addSubview:imageView]; 91     return  cell; 92 return cell; 93      94 } 95 //指定单元格的大小 96 - (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath{ 97      return CGSizeMake(self.view.frame.size.width/4-10, self.view.frame.size.width/4-10); 98  99 }100 ////设置每个cell上下左右相距101 //- (UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout insetForSectionAtIndex:(NSInteger)section{102 //    return UIEdgeInsetsMake(0, 0, 0, 0);103 //}104 ////设置最小行间距 也就是前一行和后一行的中间最小间隔105 //- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumLineSpacingForSectionAtIndex:(NSInteger)section{106 //    return 0.0f;107 //}108 //- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumInteritemSpacingForSectionAtIndex:(NSInteger)section{109 //    return 0.0f;110 //}111 #pragma mark 点击cell112 -(void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath{113     if(indexPath.row==currentImages.count)114     {115         UIActionSheet *action=[[UIActionSheet alloc] initWithTitle:@"选取照片" delegate:self cancelButtonTitle:@"取消" destructiveButtonTitle:nil otherButtonTitles:@"从摄像头选取", @"从图片库选择",nil];116         [action showInView:self.view];117     }118     else119     {120         [KevinPreViewController setPreviewImage:currentImages[indexPath.row]];121         [self.navigationController pushViewController:[[UIStoryboard storyboardWithName:@"Main" bundle:[NSBundle mainBundle]] instantiateViewControllerWithIdentifier:@"PreviewVC"] animated:YES];122     }123 124 }125 -(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info{126     [picker dismissViewControllerAnimated:YES completion:nil];127     UIImage *image=[info objectForKey:UIImagePickerControllerOriginalImage];128     NSData *tempData=UIImageJPEGRepresentation(image, 0.5f);129     image=[UIImage imageWithData:tempData];130     if(currentImages ==nil)131     {132         currentImages=[[NSMutableArray alloc] init];133     }134     [currentImages addObject:image];135     [_collectionView reloadData];136     // [self saveImage:image withName:@""]137 }138 -(void)imagePickerControllerDidCancel:(UIImagePickerController *)picker{139     [picker dismissViewControllerAnimated:YES completion:nil];140 }141 -(void)actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex{142     143     switch (buttonIndex) {144         case 0:145             [self openCamera];146             break;147         case 1:148             [self openLibary];149             break;150         default:151             break;152     }153 }154 -(void)openCamera{155     //UIImagePickerControllerSourceType *type=UIImagePickerControllerSourceTypeCamera;156     if([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera])157     {158         UIImagePickerController *picker=[[UIImagePickerController alloc] init];159         picker.delegate=self;160         picker.sourceType=UIImagePickerControllerSourceTypeCamera;161         picker.allowsEditing=YES;162         [self presentViewController:picker animated:YES completion:nil];163         164     }165 }166 -(void)openLibary{167     if([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypePhotoLibrary])168     {169         UIImagePickerController *picker=[[UIImagePickerController alloc] init];170         picker.delegate=self;171         picker.sourceType=UIImagePickerControllerSourceTypePhotoLibrary;172         picker.allowsEditing=YES;173         [self presentViewController:picker animated:YES completion:nil];174         175     }176     177 }178 -(void) saveImage:(UIImage *)image withName:(NSString *)name179 {180     NSData *imageData=UIImageJPEGRepresentation(image, 0.5);181     NSString *path=[NSTemporaryDirectory() stringByAppendingPathComponent:name];182     [imageData writeToFile:path atomically:YES];183     184 }185 +(void)deleteSelectedImage:(NSInteger)index186 {187     if(currentImages!=nil)188         [currentImages removeObjectAtIndex:index];189 }190 +(void)deleteSelectedImageWithImage:(UIImage *)image{191     if(currentImages!=nil)192         [currentImages removeObject:image];193     194 }195 196 - (void)didReceiveMemoryWarning {197     [super didReceiveMemoryWarning];198     // Dispose of any resources that can be recreated.199 }200 201 @end
     

github地址 https://github.com/wubianxiaoxian/AddPicture