UIImagePickerController（相册的使用）

此工程使用Storyboard来实现的：

#import "ViewController.h"

@interface ViewController ()<UIImagePickerControllerDelegate,UINavigationControllerDelegate>

@property (strong, nonatomic) IBOutlet UIButton *buttoon;

@property (strong, nonatomic) IBOutlet UIImageView *imageView;

@end

@implementation ViewController

- (IBAction)btAction:(UIButton *)sender {

//创建提示框 控制器

UIAlertController *alertC = [UIAlertController alertControllerWithTitle:@"提示框" message:nil preferredStyle:UIAlertControllerStyleActionSheet];

//创建相机的点击事件按钮

UIAlertAction *alertA = [UIAlertAction actionWithTitle:@"相机" style:UIAlertActionStyleDestructive handler:^(UIAlertAction *action){

//判断系统设备是否存在相机，有调用 没有提醒用户

if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {

//如果有摄像头 ,创建相机

UIImagePickerController *picker = [[ UIImagePickerController alloc] init];

//指定数据来源，来自于相机

picker.sourceType = UIImagePickerControllerSourceTypeCamera;

picker.delegate = self;

picker.allowsEditing = YES;//允许编辑

//使用模态弹出相机

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

}else {

//没有摄像头提醒用户，您的设备没有摄像头

UIAlertController *controller = [UIAlertController alertControllerWithTitle:@"您的设备没有摄像头" message:nil preferredStyle:UIAlertControllerStyleAlert];

UIAlertAction *action = [UIAlertAction actionWithTitle:@"确定" style:UIAlertActionStyleDefault handler:nil];

[controller addAction:action];

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

}

}];

[alertC addAction:alertA];//添加到提示框

//创建相册的点击事件按钮，

UIAlertAction *action = [ UIAlertAction actionWithTitle:@"相册" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action){

UIImagePickerController *picker = [[UIImagePickerController alloc] init];

picker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;//指定数据来源是相册

picker.delegate = self;

picker.allowsEditing = YES;

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

}];

[alertC addAction:action];

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

}

//选取图片之后执行的方法

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<NSString *,id> *)info{

NSLog(@"%@",info);//是个字典

//通过字典的key值来找到图片

UIImage *image = [info objectForKey:UIImagePickerControllerOriginalImage];/选取的是原始图片。还有其他的样式；如编辑的图片：UIImagePickerControllerEditedImage

//并且赋值给声明好的imageView

self.imageView.image = image;

//最后模态返回 最初的 控制器

[picker dismissViewControllerAnimated:YES completion:nil];

}

注意：使用时要接受两个协议：<UIImagePickerControllerDelegate,UINavigationControllerDelegate>，创建UIAlertController和UIAlertAction的初始化方法名的区别，其他就是其样式的选取的区别，根据自己的需求来选择样式。弹出提示框使用的是，模态的方法弹出，返回时同样使用的是模态，方法名要熟记。