ELCImagePicker相册图片多选效果

• 1.ELCImagePicker是第三方框架用来处理相册中的图片多选，在头文件中先导入#import "ELCImagePickerController.h"。实现的代码如下

 - (void)showImagePicker{
    ELCImagePickerController *imagePicker = [[ELCImagePickerController alloc] initImagePicker];
    imagePicker.maximumImagesCount = 3 - self.model.bookImageArray.count;
    imagePicker.returnsOriginalImage = YES;
    imagePicker.returnsImage = YES;
    imagePicker.onOrder = YES;
    imagePicker.mediaTypes = @[(NSString *)kUTTypeImage];
    imagePicker.imagePickerDelegate = self;
    
    [self presentViewController:imagePicker animated:YES completion:nil];
}

第一个属性设置了相册允许选择照片的最大数量，这里最多选择3张，再减去现有的图片。第二个属性允许返回原始的图片，并且按照顺序返回。重要的是要设置控制器的代理。

• 2.代理函数如下:

 #pragma mark - imagePickerController 代理
 - (void)elcImagePickerControllerDidCancel:(ELCImagePickerController *)picker {
    [picker dismissViewControllerAnimated:YES completion:nil];
}

 - (void)elcImagePickerController:(ELCImagePickerController *)picker didFinishPickingMediaWithInfo:(NSArray *)info {
    [picker dismissViewControllerAnimated:YES completion:nil];
    
    for (NSDictionary *dict in info) {
        if ([dict objectForKey:UIImagePickerControllerOriginalImage]) {
            UIImage *image = [dict objectForKey:UIImagePickerControllerOriginalImage];
            // 压缩图片
            UIImage *resizedImage = [image compressImage:300];
            [self.model.bookImageArray addObject:resizedImage];
        }
    }
    [self.imageCollectionView reloadData];
}

在代理函数中返回原始图片，在UIImage分类中写了一个函数-- (UIImage *)compressImage:(CGFloat)size 函数用来压缩图片。

真机拍照处理

• 1.由于在模拟器无法使用相机，弹出警告框，需要真机模拟，使用UIImagePickerController 控制器,代码如下:

 - (void)showCamera{
    UIImagePickerController *picker = [[UIImagePickerController alloc] init];
    picker.delegate = self;
    //    picker.allowsEditing = YES;
    // 监测权限
    AVAuthorizationStatus authStatus = [AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeVideo];
    
    if([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {
        picker.sourceType = UIImagePickerControllerSourceTypeCamera;
        [self presentViewController:picker animated:YES completion:nil];
    } else if (authStatus == AVAuthorizationStatusRestricted || authStatus ==AVAuthorizationStatusDenied) {
        UIAlertView * alart = [[UIAlertView alloc]initWithTitle:@"温馨提示" message:@"请您设置允许APP访问您的相机\n设置>隐私>相机" delegate:self cancelButtonTitle:@"确定" otherButtonTitles:nil, nil];
        [alart show];
    } else {
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"设备不支持相机！" message:@"请从相册中选取照片。" delegate:nil cancelButtonTitle:@"确定" otherButtonTitles: nil];
        [alert show];
    }
}

• 2.代理处理函数如下:

#pragma mark - UIImagePickerController代理
 - (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker{
    [picker dismissViewControllerAnimated:YES completion:nil];
}

 - (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<NSString *,id> *)info{
    [self dismissViewControllerAnimated:YES completion:nil];
    UIImage *image = info[UIImagePickerControllerOriginalImage];
    UIImage *resizedImage = [image compressImage:300];
    [self.model.bookImageArray addObject:resizedImage];
    [self.imageCollectionView reloadData];
}