最近有点懒，又是很久没有写点东西，就连日记都是前两个月才更新的。当然，找理由真的是我的强项。(哭着笑.脸)

先上效果图：
中间随便设置一个ImageView对象就行，然后直接放大招，一句话切换头像。
代码如下：

#import "ViewController.h"
#import "UIViewController+HeadFunction.h"

@interface ViewController ()
@property (nonatomic, strong) UIImageView *imageView;
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
  
    self.view.backgroundColor = [UIColor whiteColor];
    
    _imageView = [[UIImageView alloc]initWithFrame:CGRectMake(0, 0, 100, 100)];
    _imageView.center = self.view.center;
    _imageView.image = [UIImage imageNamed:@"头像"];
    _imageView.layer.cornerRadius = _imageView.frame.size.width/2;
    _imageView.layer.masksToBounds = YES;
    
    [self.view addSubview:_imageView];
    
//  是的，你没看错，就是这一句代码
    [self changeHeadImageWithHeadImageView:_imageView];
}

- (void)viewWillAppear:(BOOL)animated{

    [super viewWillAppear:YES];
    NSUserDefaults *userdefaults = [NSUserDefaults standardUserDefaults];
    // 判断沙盒里是否有图片文件
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *filePath = [[paths objectAtIndex:0] stringByAppendingPathComponent:[NSString stringWithFormat:@"%@HeadImage.png",[userdefaults stringForKey:@"123"]]];   // 保存文件的名称
    NSFileManager *fileManager = [NSFileManager defaultManager];
    BOOL result = [fileManager fileExistsAtPath:filePath];
    if (result) {
        _imageView.image = [UIImage imageWithContentsOfFile:filePath];
    }
    else {
        _imageView.image = [UIImage imageNamed:@"头像"];
    }
}
@end

上面那个- (void)viewWillAppear:(BOOL)animated的代码是为了加载出上一次运行时保存在沙盒里的图片，如果沙盒没有，就加载默认设置的。
最重要的那句代码就是这句啦：
** [self changeHeadImageWithHeadImageView:_imageView];**
我们只需要将ImageView这个对象传进去即可。

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#import "UIViewController+HeadFunction.h"
#import "UIViewController+ActionSheet.h"
#import <objc/runtime.h>

static const char *HeadManagerKey = "HeadManagerKey";
static const char *HeadPictureViewKey = "HeadPictureViewKey";

@implementation UIViewController (HeadFunction)

- (void)setHeadPictureView:(UIImageView *)headPictureView {
   // 第一个参数：给哪个对象添加关联
   // 第二个参数：关联的key，通过这个key获取
   // 第三个参数：关联的value
   // 第四个参数:关联的策略
   objc_setAssociatedObject(self, HeadPictureViewKey, headPictureView, OBJC_ASSOCIATION_ASSIGN);
}

- (UIImageView *)headPictureView {
   return objc_getAssociatedObject(self, HeadPictureViewKey);
}

- (void)setHeadManager:(HeadManager *)headManager {
   objc_setAssociatedObject(self, HeadManagerKey, headManager, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}

- (HeadManager *)headManager {
   return objc_getAssociatedObject(self, HeadManagerKey);
}

#pragma mark - ChangeHeadImage
- (void)changeHeadImageWithHeadImageView:(UIImageView *)headImageView{
   self.headPictureView = headImageView;
   UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(headImageChange:)];
   self.headPictureView.userInteractionEnabled = YES;
   [self.headPictureView addGestureRecognizer:tap];
}

- (void)headImageChange:(UIGestureRecognizer *)tap{
   
   NSNotificationCenter *notificationDefaultCenter = [NSNotificationCenter defaultCenter];
   if (tap.state == UIGestureRecognizerStateEnded) {
       self.headManager = [[HeadManager alloc] initWithTarget:self];
       __weak __typeof(self) weakSelf = self;
       self.headManager.cropImageBlock = ^(UIImage *cropImage){
           weakSelf.headPictureView.image = cropImage;
           [notificationDefaultCenter postNotificationName:headImageUpdateNotificationKey object:nil userInfo:@{headImageValue:cropImage}];
           weakSelf.headManager = nil;
       };
       [self actionSheet:^{
           [self.headManager checkCameraAvailability:^(BOOL auth) {
               if (!auth) {
                   NSLog(@"没有访问相机权限");
                   return;
               }
           }];
           
           [self.headManager openTakePhoto];
           
       } ppBlock:^{
           [self.headManager openPhotoalbums];
       }];
   }
   
}

@end

就是在这里加的tap手势：嘻嘻~~~

一句代码里的详细内容

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