iOS 系统图片选择和保存

#import "ViewController.h"
//因为会用到代理 所以要服从下面三个协议
@interface ViewController ()<UIActionSheetDelegate ,UIImagePickerControllerDelegate,UINavigationControllerDelegate>
@property (weak, nonatomic) IBOutlet UIImageView *picView;

@end

@implementation ViewController

//出现下拉菜单(这是一个button的点击事件)
- (IBAction)ButtonAction:(id)sender {

//创建一个UIAlertController 我们可以有选择的显示提示button
UIAlertController *alert=[UIAlertController alertControllerWithTitle:@"选择" message:nil preferredStyle:UIAlertControllerStyleActionSheet];

//拍照
//先检测是否有拍照功能,如果没有(为xcode模拟器) 不会弹出拍照按钮
if([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]){
UIAlertAction *action1=[UIAlertAction  actionWithTitle:@"拍照" style:(UIAlertActionStyleDefault) handler:^(UIAlertAction *action) {

[self chioceSourceType:UIImagePickerControllerSourceTypeCamera];

}];
[alert  addAction:action1];

}

//相册
UIAlertAction  *action2=[UIAlertAction actionWithTitle:@"从相册中选择" style:(UIAlertActionStyleDefault) handler:^(UIAlertAction *action) {

[self chioceSourceType:UIImagePickerControllerSourceTypeSavedPhotosAlbum];

}];

//取消
UIAlertAction *action3=[UIAlertAction actionWithTitle:@"取消" style:(UIAlertActionStyleDefault) handler:^(UIAlertAction *action) {

}];
[alert addAction:action2];
[alert addAction:action3];
[self presentViewController:alert animated:YES completion:^{

}];

}

//选择模式
-(void)chioceSourceType:(NSInteger)sourceType{

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

//设置代理
imagePicker.delegate=self;
imagePicker.allowsEditing=YES;

imagePicker.sourceType=sourceType;

[self presentViewController:imagePicker animated:YES completion:^{

}];

}

//选择图片完成后的方法
-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info{

//截取图片后执行的方法

[picker dismissViewControllerAnimated:YES completion:^{

}];
UIImage *image=[info objectForKey:UIImagePickerControllerOriginalImage];

UIImageWriteToSavedPhotosAlbum(image, self, nil, NULL);
self.picView.image=image;

}
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}

- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}