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;
在这里，我们主要使用第一个代理方法，在选取图片完成后调用，选取的信息都在info中，info 是一个字典。
// 代理方法,获取图片
// 选取的信息都在info中，info 是一个字典。
/**
// info dictionary keys
UIKIT_EXTERN NSString *const UIImagePickerControllerMediaType __TVOS_PROHIBITED;//指定用户选择的媒体类型
UIKIT_EXTERN NSString *const UIImagePickerControllerOriginalImage __TVOS_PROHIBITED;//原始图片
UIKIT_EXTERN NSString *const UIImagePickerControllerEditedImage __TVOS_PROHIBITED;//修改后的图片
UIKIT_EXTERN NSString *const UIImagePickerControllerCropRect __TVOS_PROHIBITED;//裁剪尺寸
UIKIT_EXTERN NSString *const UIImagePickerControllerMediaURL __TVOS_PROHIBITED;//媒体的URL
UIKIT_EXTERN NSString *const UIImagePickerControllerReferenceURL NS_AVAILABLE_IOS(4_1) __TVOS_PROHIBITED;//原件的URL
UIKIT_EXTERN NSString *const UIImagePickerControllerMediaMetadata NS_AVAILABLE_IOS(4_1) __TVOS_PROHIBITED;//如果是拍照的照片，则需要手动保存到本地，系统不会自动保存拍照成功后的照片
下面是具体的代码，只写了核心的部分，当你需要获取系统图片时，执行- (void)startGetPhoto;此方法即可。
//点击更换头像时开始执行此方法
- (void)startGetPhoto
{
self.actionSheet = [[UIActionSheet alloc] initWithTitle:nil
delegate:self
cancelButtonTitle:@"取消"
destructiveButtonTitle:nil
otherButtonTitles:@"相册", @"拍照", nil];
self.actionSheet.tag = ActionSheetTagAddPhoto;
[self.actionSheet showInView:self.view];
}
#pragma mark -
#pragma mark UIActionSheetDelegate Call Back Implementation
- (void)actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex
{
if (0 == buttonIndex)
{
//打开本地相册
[self localPhoto];
}
else if(1 == buttonIndex)
{
// 开始拍照
[self takePhoto];
}
}
#pragma mark -
#pragma mark UIImagePickerControllerDelegate Call Back Implementation
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
NSString *type = [info objectForKey:UIImagePickerControllerMediaType];
//当选择的类型是图片
if ([type isEqualToString:@"public.image"])
{
NSString *key = nil;
if (picker.allowsEditing)
{
key = UIImagePickerControllerEditedImage;
}
else
{
key = UIImagePickerControllerOriginalImage;
}
//获取图片
UIImage *image = [info objectForKey:key];
if (picker.sourceType == UIImagePickerControllerSourceTypeCamera) {
// 固定方向
image = [image fixOrientation];//这个方法是UIImage+Extras.h中方法
//压缩图片质量
image = [self reduceImage:image percent:0.1];
CGSize imageSize = image.size;
imageSize.height = 320;
imageSize.width = 320;
//压缩图片尺寸
image = [self imageWithImageSimple:image scaledToSize:imageSize];
}
//上传到服务器
//[self doAddPhoto:image];
//关闭相册界面
[picker dismissViewControllerAnimated:YES completion:^{
}];
}
}
// 开始拍照
-(void)takePhoto
{
if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera])
{
UIImagePickerController *picker = [[UIImagePickerController alloc] init];
picker.sourceType = UIImagePickerControllerSourceTypeCamera;
picker.delegate = self;
//设置拍照后的图片可被编辑
picker.allowsEditing = YES;
picker.sourceType = UIImagePickerControllerSourceTypeCamera;
//先检查相机可用是否
BOOL cameraIsAvailable = [self checkCamera];
if (YES == cameraIsAvailable) {
[self presentViewController:picker animated:YES completion:nil];
}else {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"提示" message:@"请在iPhone的“设置-隐私-相机”选项中，允许本应用程序访问你的相机。" delegate:self cancelButtonTitle:@"好，我知道了" otherButtonTitles:nil];
[alert show];
}
}
}
// 打开本地相册
-(void)localPhoto
{
//本地相册不需要检查，因为UIImagePickerController会自动检查并提醒
UIImagePickerController *picker = [[UIImagePickerController alloc] init];
picker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
picker.delegate = self;
//设置选择后的图片可被编辑
picker.allowsEditing = YES;
[self presentViewController:picker animated:YES completion:nil];
}
//检查相机是否可用
- (BOOL)checkCamera
{
NSString *mediaType = AVMediaTypeVideo;
AVAuthorizationStatus authStatus = [AVCaptureDevice authorizationStatusForMediaType:mediaType];
if(AVAuthorizationStatusRestricted == authStatus ||
AVAuthorizationStatusDenied == authStatus)
{
//相机不可用
return NO;
}
//相机可用
return YES;
}
//压缩图片质量
-(UIImage *)reduceImage:(UIImage *)image percent:(float)percent
{
NSData *imageData = UIImageJPEGRepresentation(image, percent);
UIImage *newImage = [UIImage imageWithData:imageData];
return newImage;
}
//压缩图片尺寸
- (UIImage*)imageWithImageSimple:(UIImage*)image scaledToSize:(CGSize)newSize
{
UIGraphicsBeginImageContext(newSize);
[image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];
UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
}
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