plist,全名PropertyList,即属性列表文件,它是一种用来存储串行化后的对象的文件。这种文件,在ios开发过程中经常被用到。这种属性列表文件的扩展名为.plist,因此通常被叫做plist文件。文件是xml格式的。Plist文件是以key-value的形式来存储数据。既可以用来存储用户设置,也可以用来存储一些需要经常用到而不经常改动的信息。
在对plist文件的操作有创建,删除,写入和读取。这四种操作中,写入和读取是比较常用的操作。
我第一次用是缓存登录信息 为了实现一键登录 免得每次都得输入账号和密码
我把整个操作plist过程封装成了类方法,因为每次都得读取路径 我以为会很慢,打算放入线程,可能是数据规模小,我就没放进线程。而且速度还是很快。
以下是类方法
@interface Function : NSObject
+(NSString *)CreateTheFolder_From:(NSString *)fileStyle FileHolderName:(NSString *)folderName FileName:(NSString *)fileName;//有文件夹则读取路径 无则创建之后再读取路径 并返回路径
+(NSString *)achieveThe_filepath:(NSString *)fileName Kind:(NSString *)fileStyle;//获取文件路径 或者文件夹路径 fileName 为文件夹名称或者带后缀的文件比如1.png
+(BOOL)judgeFileExist:(NSString * )fileName Kind:(NSString *)fileStyle;//判断文件是否存在 YES 存在 NO不存在
+(void)creatTheFile:(NSString *)fileName Kind:(NSString *)fileStyle;//创建一个名为fileName的文件
+(void)WriteToFile:(NSString *)fileName File:(NSDictionary *)dic Kind:(NSString *)fileSyle;//把file 写入名为fileName的文件
+(NSDictionary*)ReadFromFile:(NSString *)fileName Kind:(NSString *)fileStyle;//从名为fileName的文件 读取 数据内容
+(void)DeleteTheFile:(NSString *)fileName Kind:(NSString *)fileSyle;//删除文件操作
+(void)Revision_TheFile_Name:(NSString *)fileName File:(NSString *)txt Key:(NSString *)key Kind:(NSString *)fileStyle;//修改文件中某条信息记录
+(void)Delete_TotalFileFromPath:(NSString *)fileAndFolder_Path ;//删除路径下所有缓存文件包括文件夹自己
@end
//类方法的实施
#import "Function.h"
@implementation Function+(NSString*)CreateTheFolder_From:(NSString *)fileStyle FileHolderName:(NSString *)folderName FileName:(NSString *)fileName
{
//创建文件夹:
//查找路径的时候 会创建该文件夹 所以即使做删除所有文件包括文件夹后 最后查找路径的时候还是会被重新创建,这个路径就是该应用的归属 不错不是吗
NSString *filePath=[Function achieveThe_filepath:nil Kind:fileStyle];
filePath = [filePath stringByAppendingPathComponent:folderName];
BOOL isDir = NO;
NSFileManager *fileManager = [NSFileManager defaultManager];
BOOL existed = [fileManager fileExistsAtPath:filePath isDirectory:&isDir];
if ( !(isDir == YES && existed == YES) )
{
[fileManager createDirectoryAtPath:filePath withIntermediateDirectories:YES attributes:nil error:nil];
}
filePath = [filePath stringByAppendingPathComponent:fileName];
return filePath;
}
+(NSString *)achieveThe_filepath:(NSString *)fileName Kind:(NSString *)fileSyle
{
NSString *filePath;
if([fileSyle isEqual:Document])
{
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
//获取完整路径
NSString *documentsDirectory = [paths objectAtIndex:0];
filePath = [documentsDirectory stringByAppendingPathComponent:fileName];
}
else if([fileSyle isEqual:Library_Cache])
{
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
//获取完整路径
NSString *documentsDirectory = [paths objectAtIndex:0];
filePath = [documentsDirectory stringByAppendingPathComponent:fileName];
}
else//tmp
{
filePath=[NSString stringWithFormat:@"%@%@",NSTemporaryDirectory(),fileName];
}
return filePath;
}
+(BOOL)judgeFileExist:(NSString * )fileName Kind:(NSString *)fileStyle
{
NSString *filepath=[Function CreateTheFolder_From:fileStyle FileHolderName:MyFolder FileName:fileName];
NSFileManager *fileManager = [NSFileManager defaultManager];
return [fileManager fileExistsAtPath:filepath];
//返回 YES 存在 NO不存在
}
+(void)creatTheFile:(NSString *)fileName Kind:(NSString *)fileStyle
{
NSString *filepath=[Function CreateTheFolder_From:fileStyle FileHolderName:MyFolder FileName:fileName];
NSFileManager* fm = [NSFileManager defaultManager];
[fm createFileAtPath:filepath contents:nil attributes:nil];
}
+(void)WriteToFile:(NSString *)fileName File:(NSDictionary *)dic Kind:(NSString *)fileStyle
{
NSString *filepath=[Function CreateTheFolder_From:fileStyle FileHolderName:MyFolder FileName:fileName];
[dic writeToFile:filepath atomically:YES];
}
+(NSDictionary *)ReadFromFile:(NSString *)fileName Kind:(NSString *)fileStyle
{
NSString *filepath=[Function CreateTheFolder_From:fileStyle FileHolderName:MyFolder FileName:fileName];
NSDictionary* dic = [NSDictionary dictionaryWithContentsOfFile:filepath];
return dic;
}
+(void)DeleteTheFile:(NSString *)fileName Kind:(NSString *)fileSyle
{
NSString *filepath=[Function achieveThe_filepath:fileName Kind:fileSyle];
//删除文件
NSFileManager *fm = [NSFileManager defaultManager];
[fm removeItemAtPath:filepath error:nil];
if([Function judgeFileExist:fileName Kind:fileSyle])
{
NSLog(@"删除失败");
}
else
{
NSLog(@"删除成功");
}
}
+(void)Revision_TheFile_Name:(NSString *)fileName File:(NSString *)txt Key:(NSString *)key Kind:(NSString *)fileSyle
{
NSString *filepath=[Function achieveThe_filepath:fileName Kind:fileSyle];
NSMutableDictionary *applist = [[NSMutableDictionary alloc] initWithContentsOfFile:filepath];
// 修改一个plist文件数据
[applist setObject:txt forKey:key];
//修改后直接把数据再写入文件
[applist writeToFile:filepath atomically:YES];
}
+(void)Delete_TotalFileFromPath:(NSString *)fileAndFolder_Path
{
[[NSFileManager defaultManager] removeItemAtPath:fileAndFolder_Path error:nil];
}
@end
具体的使用举例
//如果当前文件不存在 则创建文件 并且插入数据
//如果存在 则更改表数据 并 读取文件内容
//功能都是封装好 独立的 也可以删除 等
......
#import "Function.h"
#define login @ "login.plist"
#define Document @ "document"
#define Library_Cache @ "library_cache"
#define Tmp @ "tmp"
......
//比如以缓存登录账号和密码为例,每次打开应用判断是否登录,如果登录过 从缓存中读取账号和密码并显示。
如方法:
//上次是否登录过
-(void)isLoad_past
{
if([Function judgeFileExist:login Kind:Library_Cache])
{
NSDictionary* dic =[Function ReadFromFile:login Kind:Library_Cache];
textField_Account.text=[dic objectForKey:@"account"];
textField_Secret.text=[dic objectForKey:@"secret"];
}
}
/*
点击登录后
判断账号密码是否存在 存在 则更新
不存在 创建文件 写入文件
方法如下
*/
if([Function judgeFileExist:login Kind:Library_Cache])
{
// [Function DeleteTheFile:login];
[Function Revision_TheFile_Name:login File:textField_Account.text Key:@"account" Kind:Library_Cache];
[Function Revision_TheFile_Name:login File:textField_Secret.text Key:@"secret" Kind:Library_Cache];
}
else
{
NSMutableDictionary *dictplist = [[NSMutableDictionary alloc ] init];
//设置属性值
[dictplist setObject:textField_Account.text forKey:@"account"];
[dictplist setObject:textField_Secret.text forKey:@"secret"];
NSDictionary *dict=dictplist;
[Function creatTheFile:login Kind:Library_Cache];
[Function WriteToFile:login File:dict Kind:Library_Cache];
}
/*
做清理缓存操作时候 删除文件夹 及里面的所有文件
做清除缓存的删除操作的集合方法举例
NSString *str1= [Function achieveThe_filepath:MyFolder Kind:Library_Cache];
[Function Delete_TotalFileFromPath:str1];
*/