沙盒

ios程序为沙盒机制,App只能访问自己目录下的文件,不能直接访问其他目录内容,每个APP默认都会创建以下目录结构Doucments Library tmp

Documents:存放应用程序产生的数据,会被iturns备份同步

Library:包含二个子目录:Cache 和 Preferences

Preferences: 包含应用程序的偏好设置文件.可以使用NSUserDefaults类来获取和设置程序的偏好,会被iturns同步

Caches : 用于存放应用程序专用的支持文件,保存应用程序再次启动过程中需要的信息,不会被iTunes备份同步

tmp: 存放临时数据,当不在用时应该删除掉临时文件,系统也有可能在程序不运行时删除该文件夹下内容

获取目录方法

Documents目录

`

NSArray *documrntDirectory = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
 NSString *pathfile = documrntDirectory.firstObject;
`

获取Library路径

`NSArray*paths=NSSearchPathForDirectoriesInDomains(NSLibraryDirectory,NSUserDomainMask,YES);

NSString*path=[paths objectAtIndex:0];
NSLog(@"path：%@",path); `

获取Caches路径

`NSArray*paths=NSSearchPathForDirectoriesInDomains(NSCachesDirectory,NSUserDomainMask,YES);

NSString*path=[paths objectAtIndex:0];
NSLog(@"path：%@",path);`

获取tmp路径

`NSString*tmp=NSTemporaryDirectory();

NSLog(@"tmp：%@",tmp);
 `

文件写入

`
 NSArray *documrntDirectory = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
 NSString *pathfile = documrntDirectory.firstObject;
 [pathfile stringByAppendingPathComponent:@"feng.txt"];

BOOL  ishave =  [[NSFileManager defaultManager]fileExistsAtPath:pathfile];
if (!ishave) {
    NSLog(@"aleady have");
    return;
}
 
NSString *str  = @"im the king of the world";
NSData *data  = [NSData dataWithContentsOfFile:str];
BOOL result = [data writeToFile:pathfile atomically:YES];
if (result) {
    NSLog(@"success");
    
}else
{
    NSLog(@"fail");
}

`

文件读取

`
 NSArray *documentsPathArr = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
 NSString *documentsPath = [documentsPathArr lastObject];
 // 拼接要写入文件的路径
 NSString *path = [documentsPath stringByAppendingPathComponent:@"feng.txt"];
 // 从路径中读取字符串
 NSString *str = [NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:nil];
 NSLog(@"%@", str);

`

得到沙盒下所有文件

`NSFileManager *fileManager = [NSFileManager defaultManager];

NSString *document=[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) .lastObject];
NSString *feng =[document stringByAppendingPathComponent:@"feng"];
NSArray *fileList ;
fileList =[fileManager contentsOfDirectoryAtPath:folder error:NULL];

for (NSString *file in fileList) {
    NSLog(@"file=%@",file);
    NSString *path =[folder stringByAppendingPathComponent:file];
    NSLog(@"得到的路径=%@",path);
}

`