ios学习笔记——保存图片到相册

最近项目要用到，这是自己练手的程序

//
//  ViewController.m
//  SJZSaveImage
//
//  Created by mac on 16/6/3.
//  Copyright © 2016年 mac. All rights reserved.
//

#import "ViewController.h"

@interface ViewController () <UIActionSheetDelegate>

@property (nonatomic, strong) UIImage * image;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    self.title = @"保存图片";
    
    UIImage * image = [UIImage imageNamed:@"saveImage.jpg"];
    self.image = image;
    
    UIImageView * imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height / 2)];
    imageView.center = self.view.center;
    imageView.image = image;
    
    [self.view addSubview:imageView];
    
    [self createButton];
}

- (void)createButton
{
    UIButton * button = [[UIButton alloc] initWithFrame:CGRectMake(40, self.view.frame.size.height * 7 / 8, self.view.frame.size.width - 80, 40)];
    button.backgroundColor = [UIColor whiteColor];
    [button setTitle:@"保存图片" forState:UIControlStateNormal];
    [button setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
    button.layer.cornerRadius = 4.0;
    [button addTarget:self action:@selector(buttonClick) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:button];
}

- (void)buttonClick
{
    if([[UIDevice currentDevice].systemVersion doubleValue] > 8.0){
        //ios8之后用UIAlertController代替UIActionSheet
        UIAlertController * alert = [UIAlertController alertControllerWithTitle:nil message:nil preferredStyle:UIAlertControllerStyleActionSheet];
        
        //增加保存图片action
        UIAlertAction *action = [UIAlertAction actionWithTitle:@"保存图片" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) {
            
            //将图片保存到相册，回调函数必须为这个形式
            UIImageWriteToSavedPhotosAlbum(self.image, self, @selector(image:didFinishSavingWithError:contextInfo:), NULL);
            
        }];
        
        [action setValue:[UIColor blackColor] forKey:@"_titleTextColor"];
        [alert addAction:action];
        
        //增加取消action
        UIAlertAction * actionCancel = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) {
            
        }];
        [actionCancel setValue:[UIColor redColor] forKey:@"_titleTextColor"];
        [alert addAction:actionCancel];
        
        [self presentViewController:alert animated:YES completion:nil];
    }else{
        UIActionSheet * action = [[UIActionSheet alloc] initWithTitle:nil delegate:self cancelButtonTitle:@"取消" destructiveButtonTitle:@"保存图片" otherButtonTitles:nil, nil];
        [action showInView:self.view];
    }
}

- (void)actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex
{
    if(buttonIndex == 0){
        //将图片保存到相册,该函数的回调必须为这种形式
        UIImageWriteToSavedPhotosAlbum(self.image, self, @selector(image:didFinishSavingWithError:contextInfo:), NULL);
    }
}

//保存图片回调函数
- (void)image: (UIImage *) image didFinishSavingWithError: (NSError *) error contextInfo: (void *) contextInfo
{
    //我们可以在这里设置弹出框
    if(error){
        NSLog(@"保存失败");
    }else{
        NSLog(@"保存成功");
    }
}

@end