前言
在开发过程，项目可能会用到手机中的一个图片，比如头像、截图等。可喜的是 iOS 系统允许第三方应用通过 UIImagePickerController 类浏览相册和使用相机应用功能，满足项目的需求。需要向系统申请相机和拍照权限，征得用户的同意，方能使用此功能。
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| <key>NSPhotoLibraryUsageDescription</key>
<string>访问相册</string>
<key>NSCameraUsageDescription</key>
<string>访问相机</string>
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系统相册和相机
首先将 UIimagePickerController 进行初始化，并遵循 UIImagePickerControllerDelegate、UINavigationControllerDelegate(可选) 协议，实现这两个协议方法。
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| - (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<NSString *,id> *)info;
- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker;
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相册
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| UIImagePickerController * imgPic = [[UIImagePickerController alloc] init];
//指定图片源类型(Library 或 Album)
imgPic.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
//imgPic.sourceType = UIImagePickerControllerSourceTypeSavedPhotosAlbum;
//遵循 协议，设置代理
imgPic.delegate = self;
//模态推出
[self presentViewController:imgPic animated:YES completion:^{}];
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| #pragma mark--协议
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<NSString *,id> *)info{
/* 图片
{
UIImagePickerControllerCropRect = "NSRect: {{0, 292}, {750, 750}}";
UIImagePickerControllerEditedImage = "<UIImage: 0x137205f00> size {750, 750} orientation 0 scale 1.000000";
UIImagePickerControllerMediaType = "public.image";
UIImagePickerControllerOriginalImage = "<UIImage: 0x137202810> size {750, 1334} orientation 0 scale 1.000000";
UIImagePickerControllerReferenceURL = "assets-library://asset/asset.PNG?id=A9B0F6F8-5D11-48EE-80AF-2BB6B850EC5C&ext=PNG";
}
*/
//1、首先判断媒体的类型
if ([info[UIImagePickerControllerMediaType] isEqualToString:(NSString *)kUTTypeImage]) {
/*
info[UIImagePickerControllerCropRect] //编辑时选取图片的位置
info[UIImagePickerControllerEditedImage] //编辑图片的对象
info[UIImagePickerControllerMediaType] //媒体的类型（视图 或者 图片）
info[UIImagePickerControllerOriginalImage] //原始图片的对象
info[UIImagePickerControllerReferenceURL] //图片的位置
*/
UIImage * originImg = info[UIImagePickerControllerOriginalImage];
//对其进行压缩
NSData * scaleImgData = UIImageJPEGRepresentation(originImg, 0.8);
}else{
}
[self dismissViewControllerAnimated:picker completion:^{ }];
}
- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker{
[self dismissViewControllerAnimated:picker completion:^{ }];
}
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注意：无论选择还是取消，最后都要在协议里执行 dismissViewControllerAnimated:completion: 方法销毁 picker 对象。
拍照
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| UIImagePickerController * takePhotos = [[UIImagePickerController alloc] init];
takePhotos.delegate = self;
//若未指定，默认是调用相册类型
takePhotos.sourceType = UIImagePickerControllerSourceTypeCamera;
//判读是否支持相机拍照
if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {
//检测硬件设备 （前后摄像头）
/*
UIImagePickerControllerCameraDeviceRear, // 后摄像头
UIImagePickerControllerCameraDeviceFront // 前摄像头
*/
if ([UIImagePickerController isCameraDeviceAvailable:UIImagePickerControllerCameraDeviceFront]) {
//指定拍照源
takePhotos.cameraDevice = UIImagePickerControllerCameraDeviceFront;
} else {
}
//设置是否允许编辑
takePhotos.allowsEditing = YES;
[self presentViewController:takePhotos animated:YES completion:^{ }];
}else{
}
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摄像
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| UIImagePickerController * pickerC = [[UIImagePickerController alloc] init];
pickerC.delegate = self;
pickerC.sourceType = UIImagePickerControllerSourceTypeCamera;
pickerC.cameraDevice = UIImagePickerControllerCameraDeviceRear;
pickerC.allowsEditing = YES;
//显示图片和视频两个选项
//pickerC.mediaTypes = [UIImagePickerController availableMediaTypesForSourceType:UIImagePickerControllerSourceTypeCamera];
//光显示视频
pickerC.mediaTypes = @[(NSString *)kUTTypeMovie];
pickerC.cameraCaptureMode = UIImagePickerControllerCameraCaptureModeVideo;
//视频质量
pickerC.videoQuality = UIImagePickerControllerQualityTypeHigh;
//隐藏系统UI default yes
pickerC.showsCameraControls = YES;
//在相机视图上添加一层视图
UIView * overlayVw = [[UIView alloc] initWithFrame:CGRectMake(0, 100, self.view.bounds.size.width, 10)];
overlayVw.backgroundColor = [UIColor redColor];
pickerC.cameraOverlayView = overlayVw;
//相机层视图旋转
//pickerC.cameraViewTransform = CGAffineTransformMakeRotation(M_PI / 2);
//缩放
//pickerC.cameraViewTransform = CGAffineTransformMakeScale(0.8, 0.5);
[self presentViewController:pickerC animated:YES completion:^{ }];
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