數(shù)據(jù)轉(zhuǎn)換
NSData -->UIImage
[UIImage imageWithData:<#(NSData *)#>];
UIImage --> NSData
NSData * data = UIImagePNGRepresentation(_imageView.image);
NSData --> NSString
NSString * string = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
NSString --> NSData
NSData * data = [@"aaa" dataUsingEncoding:NSUTF8StringEncoding];
漢字 轉(zhuǎn)換成 電腦能是別的碼
[@"甄嬛傳" stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
//通過fileManager獲取到指定路徑下文件的所有屬性榕暇，得到一個(gè)字典
NSDictionary *attDic = [[NSFileManager defaultManager] attributesOfItemAtPath:path error:nil];
文件寫入寫出常用函數(shù)
-(BOOL)writeToFile:(NSString *)path atomically:(BOOL)flag;
-(id)initWithContentsOfFile:(NSString *)path;
如果文件中內(nèi)容少的用NSUserDefaults，多的也可用SOL或者XML。
獲取文件創(chuàng)建時(shí)間和大小的代碼
NSDictionary *fileAttributes = [[NSFileManager defaultManager] fileAttributesAtPath:path traverseLink:YES]懈玻；
image png,jpg格式判斷
image?= [info?objectForKey:@"UIImagePickerControllerOriginalImage"];
NSData?*data;
if?(UIImagePNGRepresentation(image) ==?nil) {
data =?UIImageJPEGRepresentation(image,?1);
}?else?{
data =?UIImagePNGRepresentation(image);
}
