NSSTring 的分类

.h

#import｛Foundation/Foundation.h｝

@interfaceNSString (Helper)

/**

*清空字符串中的空白字符

*

*@return清空空白字符串之后的字符串

*/

- (NSString*)trimString;

/**

*是否空字符串

*

*@return如果字符串为nil或者长度为0返回YES

*/

- (BOOL)isEmptyString;

/**

*返回沙盒中的文件路径

*

*@return返回当前字符串对应在沙盒中的完整文件路径

*/

- (NSString*)documentsPath;

/**

*写入系统偏好

*

*@paramkey写入键值

*/

- (void)saveToNSDefaultsWithKey:(NSString*)key;

.m

#import"NSString+Helper.h"

@implementationNSString (Helper)

#pragma mark清空字符串中的空白字符

- (NSString*)trimString

{

return[selfstringByTrimmingCharactersInSet:[NSCharacterSetwhitespaceAndNewlineCharacterSet]];

}

#pragma mark是否空字符串

- (BOOL)isEmptyString

{

return(self==nil||self.length==0);

}

#pragma mark返回沙盒中的文件路径

- (NSString*)documentsPath

{

NSString*path =NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES)[0];

return[pathstringByAppendingString:self];

}

#pragma mark写入系统偏好

- (void)saveToNSDefaultsWithKey:(NSString*)key

{

[[NSUserDefaultsstandardUserDefaults]setObject:selfforKey:key];

[[NSUserDefaultsstandardUserDefaults]synchronize];

}

@end