iOS在更改用户头像并保存至本地沙盒目录中对于UIImagePickerController、UIAlertController的使用

.h
#import <UIKit/UIKit.h>//获取系统版本号#define IS_iOS8 ([[[UIDevice currentDevice] systemVersion] floatValue] >= 8.0 ? YES : NO)//获取屏幕尺寸#define SW [UIScreen mainScreen].bounds.size.width#define SH [UIScreen mainScreen].bounds.size.height@interface ViewController : UIViewController<UINavigationControllerDelegate,UIImagePickerControllerDelegate,UIActionSheetDelegate>@property (nonatomic, strong)UIButton *iconBtn;@end
.m
- (void)viewDidLoad {    [super viewDidLoad];    //初始化Button    _iconBtn = [[UIButton alloc]initWithFrame:CGRectMake((SW - 100)/2,(SH / 3) - 100,100,100)];    _iconBtn.backgroundColor =[UIColor redColor];    //加载首先访问本地沙盒是否存在相关图片    NSString *fullPath = [[NSHomeDirectory() stringByAppendingPathComponent:@"Documents"] stringByAppendingPathComponent:@"currentImage.png"];        UIImage *savedImage = [UIImage imageWithContentsOfFile:fullPath];    if (!savedImage)    {        //默认头像        [_iconBtn setImage:[UIImage imageNamed:@"head"] forState:UIControlStateNormal];    }    else    {        [_iconBtn setImage:savedImage forState:UIControlStateNormal];    }    _iconBtn.layer.masksToBounds = YES;    _iconBtn.layer.cornerRadius = _iconBtn.frame.size.height / 2;    [_iconBtn addTarget:self action:@selector(changeIcon) forControlEvents:UIControlEventTouchUpInside];    [self.view addSubview:_iconBtn];}- (void)changeIcon{    UIAlertController *alertController;    __block NSUInteger blockSourceType = 0;    // 判断是否支持相机    if([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera])    {        //支持访问相机与相册情况        alertController = [UIAlertController alertControllerWithTitle:nil message:nil preferredStyle:UIAlertControllerStyleActionSheet];        [alertController addAction:[UIAlertAction actionWithTitle:@"从相册中选取" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {            NSLog(@"点击从相册中选取");            //相册            blockSourceType = UIImagePickerControllerSourceTypePhotoLibrary;            UIImagePickerController *imagePickerController = [[UIImagePickerController alloc] init];            imagePickerController.delegate = self;            imagePickerController.allowsEditing = YES;            imagePickerController.sourceType = blockSourceType;            [self presentViewController:imagePickerController animated:YES completion:nil];        }]];        [alertController addAction:[UIAlertAction actionWithTitle:@"拍照" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {            NSLog(@"点击拍照");            //相机            blockSourceType = UIImagePickerControllerSourceTypeCamera;            UIImagePickerController *imagePickerController = [[UIImagePickerController alloc] init];            imagePickerController.delegate = self;            imagePickerController.allowsEditing = YES;            imagePickerController.sourceType = blockSourceType;            [self presentViewController:imagePickerController animated:YES completion:nil];        }]];        [alertController addAction:[UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) {            NSLog(@"点击取消");            // 取消            return;        }]];        [self presentViewController:alertController animated:YES completion:nil];    }    else    {        //只支持访问相册情况        alertController = [UIAlertController alertControllerWithTitle:nil message:nil preferredStyle:UIAlertControllerStyleActionSheet];        [alertController addAction:[UIAlertAction actionWithTitle:@"从相册中选取" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {            NSLog(@"点击从相册中选取");            //相册            blockSourceType = UIImagePickerControllerSourceTypePhotoLibrary;            UIImagePickerController *imagePickerController = [[UIImagePickerController alloc] init];            imagePickerController.delegate = self;            imagePickerController.allowsEditing = YES;            imagePickerController.sourceType = blockSourceType;            [self presentViewController:imagePickerController animated:YES completion:^{            }];        }]];        [alertController addAction:[UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) {            NSLog(@"点击取消");            // 取消            return;        }]];        [self presentViewController:alertController animated:YES completion:nil];    }}#pragma mark - 选择图片后,回调选择- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info{    [picker dismissViewControllerAnimated:YES completion:nil];    UIImage *image = [info objectForKey:UIImagePickerControllerEditedImage];    /* 此处info 有六个可选类型     * UIImagePickerControllerMediaType; // an NSString UTTypeImage)     * UIImagePickerControllerOriginalImage;  // a UIImage 原始图片     * UIImagePickerControllerEditedImage;    // a UIImage 裁剪后图片     * UIImagePickerControllerCropRect;       // an NSValue (CGRect)     * UIImagePickerControllerMediaURL;       // an NSURL     * UIImagePickerControllerReferenceURL    // an NSURL that references an asset in the AssetsLibrary framework     * UIImagePickerControllerMediaMetadata    // an NSDictionary containing metadata from a captured photo     */    [_iconBtn setImage:image forState:UIControlStateNormal];    [self saveImage:image withName:@"currentImage.png"];}#pragma mark - 保存图片至本地沙盒- (void)saveImage:(UIImage *)currentImage withName:(NSString *)imageName{    NSData *imageData = UIImageJPEGRepresentation(currentImage, 0.8);    // 获取沙盒目录    NSString *fullPath = [[NSHomeDirectory() stringByAppendingPathComponent:@"Documents"] stringByAppendingPathComponent:imageName];    // 将图片写入文件    [imageData writeToFile:fullPath atomically:NO];}