iOS调用摄像头和相册选取图片

iOS图片来源有三种方法：

typedef NS_ENUM(NSInteger, UIImagePickerControllerSourceType) {
    UIImagePickerControllerSourceTypePhotoLibrary,    //1.从图库中选择
    UIImagePickerControllerSourceTypeCamera,          //2.直接调用摄像头拍照
    UIImagePickerControllerSourceTypeSavedPhotosAlbum //3.从相册中选择
} __TVOS_PROHIBITED;

UIImagePickerController是系统提供的用来获取图片和视频的接口，用UIImagePickerController类来获取图片视频，大体分为以下几个步骤：

1. 实例化UIImagePickerController
2. 设置UIImagePickerController数据来源类型
3. 设置代理，遵循UIImagePickerControllerDelegate,UINavigationControllerDelegate协议
4. 实现代理方法接收选取图片并做处理

在代理中获取我们选中的图片，UIImagePickerControllerDelegate代理中一共三个方法，其中一个3.0已经废弃了，只剩下两个我们需要用的。

//1.当用户选取完成后调用；
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info;
 
//2.当用户取消选取时调用；
- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker;

我们主要使用第一个代理方法，在选取图片完成后会调用，返回一个info字典。

实际使用展示：

@interface SelecteImageViewController ()<UIImagePickerControllerDelegate, UINavigationControllerDelegate>
@property (nonatomic, strong) UIImagePickerController *picker;
@property (nonatomic, strong) UIImageView *selectImageView;
@end

@implementation SelecteImageViewController

- (void)imageViewDidClick:(UIImageView *)imageView ForIndex:(NSInteger)index {
    UIAlertController *alertController = [UIAlertController alertControllerWithTitle:nil message:nil preferredStyle:UIAlertControllerStyleActionSheet];
    [alertController addAction:[UIAlertAction actionWithTitle:@"相机" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
        
        [weakSelf goCameraViewController];
    }]];
    
    [alertController addAction:[UIAlertAction actionWithTitle:@"相册" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
        
        [weakSelf directGoPhotoViewController];
    }]];
    
    [alertController addAction:[UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:nil]];
    
    [self presentViewController:alertController animated:YES completion:nil];
}

-(void)goCameraViewController {
    // 如果摄像头可用
    if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {
        //
        self.picker.sourceType = UIImagePickerControllerSourceTypeCamera;
        self.picker.cameraCaptureMode = UIImagePickerControllerCameraCaptureModePhoto;
        self.picker.cameraDevice = UIImagePickerControllerCameraDeviceRear;
    } else {
        [XWHUDManager showErrorTipHUD:@"无法打开摄像头"];
        return;
    }
    [self presentViewController:self.picker animated:YES completion:nil];
}

-(void)directGoPhotoViewController {
    self.picker.sourceType = UIImagePickerControllerSourceTypeSavedPhotosAlbum;
    [self presentViewController:self.picker animated:YES completion:nil];
}

/**
 拍照或选择图片后的回调

 @param picker <#picker description#>
 @param info <#info description#>
 */
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<UIImagePickerControllerInfoKey,id> *)info {
    FTLog(@"info--->成功：%@", info);
    // 获取用户拍摄的是照片还是视频
    NSString *mediaType = [info objectForKey:UIImagePickerControllerMediaType];
    // 判断获取类型：图片，并且是刚拍摄的照片
    if ([mediaType isEqualToString:(NSString *)kUTTypeImage] && picker.sourceType == UIImagePickerControllerSourceTypeCamera) {
        
        UIImage *theImage = nil;
        // 判断，图片是否允许修改
        if ([picker allowsEditing]) {
            // 获取用户遍及之后的图像
            theImage = [info objectForKey:UIImagePickerControllerEditedImage];
        } else {
            // 获取原始图像
            theImage = [info objectForKey:UIImagePickerControllerOriginalImage];
        }
        // 保存图片到相册中
        UIImageWriteToSavedPhotosAlbum(theImage, self, nil, nil);
    }
    [picker dismissViewControllerAnimated:YES completion:nil];
}

-(UIImagePickerController *)picker {
    if (!_picker) {
        _picker = [[UIImagePickerController alloc] init];
        _picker.delegate = self;
        _picker.editing = YES;
    }
    return _picker;
}

@end