photo

//
//  ViewController.m
//  获取相册图片
//
//  Created by xiaomage on 16/4/19.
//  Copyright © 2016年 小码哥. All rights reserved.
//

/*
 获取相册中的图片
 1.单张
 1> UIImagePickerController
 2> AssetsLibrary框架
 3> Photos框架
 
 2.多张(>=2张)
 1> AssetsLibrary框架
 2> Photos框架（推荐）
 */

#import "ViewController.h"
#import <Photos/Photos.h>
#import <CTAssetsPickerController/CTAssetsPickerController.h>

@interface ViewController () <CTAssetsPickerControllerDelegate>
@property (nonatomic , strong) NSMutableArray *assets;
@end

@implementation ViewController
-(NSMutableArray *)assets{
    if (_assets == nil) {
        _assets = [NSMutableArray array];
    }
    return _assets;
}
/*
 // Optionally present picker as a form sheet on iPad
 if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)
 picker.modalPresentationStyle = UIModalPresentationFormSheet;
 */

/*
 Attempt to present <UIAlertController: 0x7f893dd34270> on <ViewController: 0x7f893b557830> whose view is not in the window hierarchy
 
 [a modal出: d] : a必须在window上
 */

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    
    // github的搜索关键字：image picker photo asset
}

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
    [PHPhotoLibrary requestAuthorization:^(PHAuthorizationStatus status){
        if (status != PHAuthorizationStatusAuthorized) return;
        
        dispatch_async(dispatch_get_main_queue(), ^{
            CTAssetsPickerController *picker = [[CTAssetsPickerController alloc] init];
            picker.selectedAssets = self.assets;
            
            picker.delegate = self;
            // 显示选择的索引
            picker.showsSelectionIndex = YES;
            // 设置相册的类型：相机胶卷 + 自定义相册
            picker.assetCollectionSubtypes = @[
              @(PHAssetCollectionSubtypeSmartAlbumUserLibrary),
              @(PHAssetCollectionSubtypeAlbumRegular)];
            // 不需要显示空的相册
            picker.showsEmptyAlbums = NO;
            [self presentViewController:picker animated:YES completion:nil];
        });
    }];
}

#pragma mark - <CTAssetsPickerControllerDelegate>
- (BOOL)assetsPickerController:(CTAssetsPickerController *)picker shouldSelectAsset:(PHAsset *)asset
{
    NSInteger max = 10;
    
    if (picker.selectedAssets.count >= max) {
        UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"提示" message:[NSString stringWithFormat:@"最多选择%zd张图片", max] preferredStyle:UIAlertControllerStyleAlert];
        [alert addAction:[UIAlertAction actionWithTitle:@"好的" style:UIAlertActionStyleDefault handler:nil]];
        [picker presentViewController:alert animated:YES completion:nil];
        // 这里不能使用self来modal别的控制器，因为此时self.view不在window上
        return NO;
    }
    
    return YES;
}

- (void)assetsPickerController:(CTAssetsPickerController *)picker didFinishPickingAssets:(NSArray *)assets
{
    // 关闭图片选择界面
    [picker dismissViewControllerAnimated:YES completion:nil];
    
    // 基本配置
    CGFloat scale = [UIScreen mainScreen].scale;
    PHImageRequestOptions *options = [[PHImageRequestOptions alloc] init];
    options.resizeMode   = PHImageRequestOptionsResizeModeExact;
    options.deliveryMode = PHImageRequestOptionsDeliveryModeHighQualityFormat;
    self.assets = [NSMutableArray arrayWithArray:assets];
    // 遍历选择的所有图片
    for (NSInteger i = 0; i < assets.count; i++) {
        PHAsset *asset = assets[i];
        CGSize size = CGSizeMake(asset.pixelWidth / scale, asset.pixelHeight / scale);
        
        // 获取图片
        [[PHImageManager defaultManager] requestImageForAsset:asset targetSize:size contentMode:PHImageContentModeDefault options:options resultHandler:^(UIImage * _Nullable result, NSDictionary * _Nullable info) {
            UIImageView *imageView = [[UIImageView alloc] init];
            imageView.image = result;
            imageView.frame = CGRectMake((i % 3) * 110, (i / 3) * 110, 100, 100);
            [self.view addSubview:imageView];
        }];
    }
}
@end