iOS系统相机的使用

这篇文章主要说明一下iOS系统相机的基本功能，能使用系统相机进行拍照和保存，或者进入图库、相册选取照片。

授权

iOS10之后，使用相机以及相册功能需要在plist文件中添加权限：

     相机权限： Privacy - Camera Usage Description
     相册权限： Privacy - Photo Library Usage Description

程序安装后首次使用相机功能系统会弹出一个授权窗口，

屏幕快照 2017-03-07 11.46.49.png

相册也是

屏幕快照 2017-03-07 11.47.00.png

这个窗口只弹出一次，要改动的话需要在设置页面进行设置。
如果想要拦截这个窗口的点击事件，需要导入两个框架：

#import <AVFoundation/AVFoundation.h>  相机
#import <Photos/Photos.h>相册

    AVAuthorizationStatus status = [AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeVideo];
    switch (status) {
        case AVAuthorizationStatusNotDetermined:{
            //程序是第一次启动，发起授权许可，不管用户接受还是拒绝，只会弹出一次
            [AVCaptureDevice requestAccessForMediaType:AVMediaTypeVideo completionHandler:^(BOOL granted) {
                if (granted) {
                    //第一次用户接受
                    NSLog(@"用户接受");
                }else{
                    //用户拒绝
                    NSLog(@"用户拒绝");
                }
            }];
            break;
        }
        case AVAuthorizationStatusAuthorized:{
            // 已经开启授权，可继续
            NSLog(@"已开启相机权限");
            break;
        }
        case AVAuthorizationStatusDenied:
        case AVAuthorizationStatusRestricted:
            // 用户已经拒绝过授权，或者相机设备无法访问
            NSLog(@"没有权限");
            break;
        default:
            break;
    }

    [PHPhotoLibrary requestAuthorization:^(PHAuthorizationStatus status) {
        dispatch_async(dispatch_get_main_queue(), ^{
            if (status == PHAuthorizationStatusRestricted || status == PHAuthorizationStatusDenied)
            {
                // 用户拒绝，跳转到自定义提示页面
                NSLog(@"用户拒绝");
            }
            else if (status == PHAuthorizationStatusAuthorized)
            {
                // 用户授权，弹出相册对话框
                NSLog(@"用户同意");
            }
        });
    }];

使用

    UIImagePickerController *_imagePickerController;
    _imagePickerController = [[UIImagePickerController alloc] init];
    _imagePickerController.delegate = self;
    /*
     UIImagePickerControllerSourceTypePhotoLibrary, 图库
     UIImagePickerControllerSourceTypeCamera,   相机
     UIImagePickerControllerSourceTypeSavedPhotosAlbum  相册
     打开类型，默认为图库
     */
    _imagePickerController.sourceType = UIImagePickerControllerSourceTypeCamera;
    /*
     UIModalTransitionStyleCoverVertical = 0,   底部滑入
     UIModalTransitionStyleFlipHorizontal,  水平翻转
     UIModalTransitionStyleCrossDissolve,   交叉溶解
     UIModalTransitionStylePartialCurl, 翻页
     弹出动画效果
     */
    _imagePickerController.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
    _imagePickerController.allowsEditing = YES; //允许编辑，设为NO则直接选中，YES可以调整位置
    
    BOOL camera = [UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera];  //是否支持相机功能，其他类型也可判断
    NSLog(@"%d",camera);
    
    /*
     UIImagePickerControllerQualityTypeHigh = 0,       // highest quality
     UIImagePickerControllerQualityTypeMedium = 1,     // medium quality, suitable for transmission via Wi-Fi
     UIImagePickerControllerQualityTypeLow = 2,         // lowest quality, suitable for tranmission via cellular network
     UIImagePickerControllerQualityType640x480 NS_ENUM_AVAILABLE_IOS(4_0) = 3,    // VGA quality
     UIImagePickerControllerQualityTypeIFrame1280x720 NS_ENUM_AVAILABLE_IOS(5_0) = 4,
     UIImagePickerControllerQualityTypeIFrame960x540 NS_ENUM_AVAILABLE_IOS(5_0) = 5,
     
     拍摄的照片质量，用于不同网络状态下，比如wifi下发送高、中质量的图片，蜂窝数据下发送低质量的图片，默认中等
     */
    _imagePickerController.videoQuality = UIImagePickerControllerQualityTypeHigh;
    
    /*
     UIImagePickerControllerCameraDeviceRear,   后置摄像头
     UIImagePickerControllerCameraDeviceFront   前置摄像头
     默认后置摄像头，注意：只有在相机类型时才可使用
     */
    if (_imagePickerController.sourceType == UIImagePickerControllerSourceTypeCamera) {
        _imagePickerController.cameraDevice = UIImagePickerControllerCameraDeviceRear;
    }
    
    /*
     typedef NS_ENUM(NSInteger, UIImagePickerControllerCameraFlashMode) {
     UIImagePickerControllerCameraFlashModeOff  = -1,   关闭闪光灯
     UIImagePickerControllerCameraFlashModeAuto = 0,    自动
     UIImagePickerControllerCameraFlashModeOn   = 1 开启
     默认自动,注意：只有在相机类型时才可使用
     */
    if (_imagePickerController.sourceType == UIImagePickerControllerSourceTypeCamera) {
        _imagePickerController.cameraFlashMode = UIImagePickerControllerCameraFlashModeAuto;
    }
    
    if (_imagePickerController.sourceType == UIImagePickerControllerSourceTypeCamera) {
        _imagePickerController.showsCameraControls = YES;    //显示默认UI，NO会隐藏掉标准UI
    }

上面只是创建了一个相机对象，需要把它显示出来

[self presentViewController:_imagePickerController animated:YES completion:nil];

协议

使用系统相机需要遵循两个协议

<UIImagePickerControllerDelegate,UINavigationControllerDelegate>

#pragma mark UIImagePickerControllerDelegate
//保存图片到相册
- (void)image:(UIImage *)image didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo
{
    NSString *msg = nil;
    if (!error) {
        msg = @"图片保存成功";
    }
    else {
        msg = @"图片保存失败";
    }
    NSLog(@"%@",msg);
}

//点击使用按钮
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<NSString *,id> *)info{
    
    if (picker.sourceType == UIImagePickerControllerSourceTypeCamera) {
        _imgView.image = info[@"UIImagePickerControllerOriginalImage"];//在打开相机后拍的照等于_imageView.image,照到有两个选项，一个重照，一个等于
    }
    else {
        NSLog(@"info = %@",info);
        //获取用户编辑之后的图片
        _imgView.image = info[@"UIImagePickerControllerEditedImage"];
    }
    [self dismissViewControllerAnimated:YES completion:nil];

    [self saveImageToPhotosAlbum];
}

//点击返回按钮
- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker {
    NSLog(@"返回");
    [_imagePickerController dismissViewControllerAnimated:YES completion:nil];
}

保存图片到相册

//保存图片到相册
- (void)saveImageToPhotosAlbum {
    //保存图片到相册函数
    UIImageWriteToSavedPhotosAlbum(_imgView.image, self, @selector(image:didFinishSavingWithError:contextInfo:), NULL);
}

     还有如果默认UI下显示的文本为英文，在plist文件中找到Localization native development region，value改成china即可编程中文