iOS-从网络下载图片,保存,并用imageview从保存中显示

-(UIImage *) getImageFromURL:(NSString *)fileURL {

     NSLog( @" 执行图片下载函数 ");

     UIImage * result; NSData * data = [NSData dataWithContentsOfURL:[NSURL URLWithString:fileURL]]; 

     result = [UIImage imageWithData:data];

        return result;

}

-( void) saveImage:(UIImage *)image withFileName:(NSString *)imageName ofType:(NSString *)extension inDirectory:(NSString *)directoryPath {

        if ([[extension lowercaseString] isEqualToString: @" png "]) { 

             [UIImagePNGRepresentation(image) writeToFile:[directoryPath stringByAppendingPathComponent:[NSString      

                stringWithFormat: @" %@.%@ ", imageName,  @" png "]] options:NSAtomicWrite error:nil]; 

     }  else  if ([[extension lowercaseString] isEqualToString: @" jpg "] || [[extension lowercaseString] isEqualToString: @" jpeg "]) {   

              [UIImageJPEGRepresentation(image,  1.0) writeToFile:[directoryPath stringByAppendingPathComponent:[NSString     

                stringWithFormat: @" %@.%@ ", imageName,  @" jpg "]] options:NSAtomicWrite error:nil]; 

     }  else {   // ALog(@"Image Save Failed\nExtension: (%@) is not recognized, use (PNG/JPG)", extension);

            NSLog( @" 文件后缀不认识 ");

     }

}

-(UIImage *) loadImage:(NSString *)fileName ofType:(NSString *)extension inDirectory:(NSString *)directoryPath { 

     UIImage * result = [UIImage imageWithContentsOfFile:[NSString stringWithFormat: @" %@/%@.%@ ", directoryPath, fileName,             

            extension]];

        return result;

}

NSString * documentsDirectoryPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex: 0]; 

 NSLog( @" 保存路径:%@ ",documentsDirectoryPath);

    // Get Image From URL

UIImage * imageFromURL = [self getImageFromURL: @" http://file.duteba.com/phone/2009/04/5/ftGxL8kcUL.jpg "];

    // Save Image to Directory

[self saveImage:imageFromURL withFileName: @" MyImage " ofType: @" jpg " inDirectory:documentsDirectoryPath];

    // Load Image From Directory

UIImage * imageFromWeb = [self loadImage: @" MyImage " ofType: @" jpg " inDirectory:documentsDirectoryPath];

 [img setImage:imageFromWeb];

    // 取得目录下所有文件名 

 NSArray *file = [[[NSFileManager alloc] init] subpathsAtPath:documentsDirectoryPath];

    // NSLog(@"%d",[file count]) ;

NSLog( @" %@ ",file); 

    // 如何获取下载的文件的完整路径?

NSString *documentsDirectory2 = [path2 objectAtIndex: 0];

   // path数组里貌似只有一个元素   // 字符串拼接得到文件完整路径

NSString *filestr =  @" /MyImage.jpg "; NSString *newstr = [documentsDirectory2 stringByAppendingString:filestr]; 

 NSLog( @" 完整路径是:%@ ",newstr); 

 NSData *dd = [NSData dataWithContentsOfFile:newstr]; 

 [img222 setImage:[UIImage imageWithData:dd]];