iOS 网络与多线程－－6.下载并保存网络图片
使用二进制数据对象的,从制定网站获取数据的方法,下载网络图片,并转化为二进制数据,然后将二进制数据保存到磁盘
按照注释需要进行阅读以下代码
1 // Created by JinXin on 15/12/2. 2 // Copyright © 2015年 JinXin. All rights reserved. 3 // 4 5 #import "ViewController.h" 6 7 @interface ViewController () 8 @end 9 10 @implementation ViewController 11 12 - (void)viewDidLoad { 13 [super viewDidLoad]; 14 // Do any additional setup after loading the view, typically from a nib. 15 16 // 5.获取项目沙箱中的Documents文件夹。 17 NSString *documentsDirectoryPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, 18 NSUserDomainMask, YES) objectAtIndex:0]; 19 // 6.获取网络图片 20 UIImage *imageFromURL = [self getImageFromURL:@"http://face.weiphone.net/data/avatar/001/27/35/59_avatar_big.jpg"]; 21 // 7.将图片保存到磁盘 22 [self saveImage:imageFromURL withFileNmae:@"image" ofType:@"jpg" inDirectory:documentsDirectoryPath]; 23 // 7.输出路径 24 NSLog(@"Path of saved image:%@",documentsDirectoryPath); 25 26 } 27 28 // 1.创建一个方法,用来获取网络图片,参数为图片的网络路径 29 -(UIImage *)getImageFromURL:(NSString *)fileURL 30 { 31 NSLog(@"Getting image........"); 32 UIImage *result; 33 34 // 2.获取网络图片,并将数据存入二进制数据对象 35 NSData *data = [NSData dataWithContentsOfURL:[NSURL URLWithString:fileURL]]; 36 // 3.将二进制数据转为图像 37 result = [UIImage imageWithData:data]; 38 // 4.返回结果 39 return result; 40 } 41 42 // 2.创建一个方法,用来将图像保存到磁盘 43 // 参数1.UIImage 对象 44 // 参数2.文件名 45 // 参数3.文件类型 46 // 参数4.保存文件的路径 47 -(void)saveImage:(UIImage *)image withFileNmae:(NSString *)imageName ofType:(NSString *)extension 48 inDirectory:(NSString *)directoryPath 49 { 50 // 3.检测图片扩展名,如果是png后缀,则使用UIImagePNGRepresentation方法,将图片转为二进制数据,并写入磁盘 51 if ([[extension lowercaseString] isEqualToString:@"png"]) 52 { 53 [UIImagePNGRepresentation(image) writeToFile:[directoryPath stringByAppendingPathComponent: 54 [NSString stringWithFormat:@"%@.%@",imageName,@"png"]] options:NSAtomicWrite error:nil]; 55 } 56 // 4. 检测图片扩展名,如果是jpg后缀,则使用UIImageJPEGRepresentation方法,将图片转为二进制数据,并写入磁盘 57 else if ([[extension lowercaseString] isEqualToString:@"jpg"] || [[extension lowercaseString] isEqualToString:@"jpeg"] ) 58 { 59 [UIImageJPEGRepresentation(image, 1.0) writeToFile:[directoryPath stringByAppendingPathComponent: 60 [NSString stringWithFormat:@"%@.%@",imageName,@"jpg"]] options:NSAtomicWrite error:nil]; 61 } 62 } 63 64 - (void)didReceiveMemoryWarning { 65 [super didReceiveMemoryWarning]; 66 // Dispose of any resources that can be recreated. 67 } 68 69 @end
输出结果：
1 2015-12-04 21:58:47.132 AppDemo[1030:104437] Getting image........ 2 2015-12-04 21:58:47.312 AppDemo[1030:104437] Path of saved image:/Users/jinxin/Library/Developer/CoreSimulator/Devices/78B0547C-FAC7-4343-AAF0-EEB564932491/data/Containers/Data/Application/5051F20E-5736-46DC-BC4E-C00D9F9CDDFF/Documents
之后打开finder 按Shift+Command+G 将路径粘贴进去 进入目录
将可以看到下载到的图片了
