IOS 文件读写操作详解及简单实例

iphone 文件读写操作

1，写文件操作

- (ibaction)btnwrite:(id)sender {
  //创建文件管理器
  nsfilemanager *filemanager = [nsfilemanager defaultmanager];
  //获取路径
  //参数 要获取的哪种路径
  nsarray *paths = nssearchpathfordirectoriesindomains(nsdocumentdirectory, nsuserdomainmask, yes);
  nsstring *documentdirectory = [paths objectatindex:0];//去除需要的路径
  //更改到操作的目录下
  [filemanager changecurrentdirectorypath:[documentdirectory stringbyexpandingtildeinpath]];
   //创建文件filename文件名称，contents文件内容，如果开始没有内容可以设置为nil，attributes文件的属性,初始为nil
  [filemanager createfileatpath:@"filename" contents:nil attributes:nil];
  //删除待删除文件
  [filemanager removeitematpath:@"createnewfile" error:nil];
  //获取文件路径
  nsstring *path = [documentdirectory stringbyappendingpathcomponent:@"filename"];
  nslog(@"path == %@",path);
  //待写入的数据
  nsstring *temp = @"hello world";
  int data0 = 1000000;
  float data2 = 23.23f;
  //创建数据缓冲
  nsmutabledata *writer = [[nsmutabledata alloc]init];
  //将字符串添加到缓冲中
  [writer appenddata:[temp datausingencoding:nsutf8stringencoding]];
  [writer appendbytes:&data0 length:sizeof(data0)];
  [writer appendbytes:&data2 length:sizeof(data2)];
   
  [writer writetofile:path atomically:yes];
  [writer release];  
}

2，读文件操作

- (ibaction)btnread:(id)sender {
  //创建文件管理器
  nsfilemanager *filemanager = [nsfilemanager defaultmanager];
  //获取路径
  //参数 要获取的哪种路径
  nsarray *paths = nssearchpathfordirectoriesindomains(nsdocumentdirectory, nsuserdomainmask, yes);
  nsstring *documentdirectory = [paths objectatindex:0];//去除需要的路径
  //更改到操作的目录下
  [filemanager changecurrentdirectorypath:[documentdirectory stringbyexpandingtildeinpath]];
   //创建文件filename文件名称，contents文件内容，如果开始没有内容可以设置为nil，attributes文件的属性,初始为nil
  [filemanager createfileatpath:@"filename" contents:nil attributes:nil];
  //删除待删除文件
  [filemanager removeitematpath:@"createnewfile" error:nil];
  //获取文件路径
  nsstring *path = [documentdirectory stringbyappendingpathcomponent:@"filename"];
  nslog(@"path == %@",path);
  //待写入的数据
  nsstring *temp = @"hello world";
  int data0 = 1000000;
  float data2 = 23.23f;
  //创建数据缓冲
  nsmutabledata *writer = [[nsmutabledata alloc]init];
  //将字符串添加到缓冲中
  [writer appenddata:[temp datausingencoding:nsutf8stringencoding]];
  [writer appendbytes:&data0 length:sizeof(data0)];
  [writer appendbytes:&data2 length:sizeof(data2)];
   
  [writer writetofile:path atomically:yes];
  [writer release];
  
  //读取操作
  int gdata0;
  float gdata1;
  nsstring *gdata2;
  
  nsdata *reader = [nsdata datawithcontentsoffile:path];
  gdata2 = [[nsstring alloc]initwithdata:[reader subdatawithrange:nsmakerange(0, [temp length])] encoding:nsutf8stringencoding];
  [reader getbytes:&gdata0 range:nsmakerange([temp length], sizeof(gdata0))];
  [reader getbytes:&gdata1 range:nsmakerange([temp length]+ sizeof(gdata0) , sizeof(gdata1))];
  nslog(@"gdata0 == %d",gdata0);
  nslog(@"gdata1 == %f",gdata1);
  nslog(@"gdata2 == %@",gdata2);
  
  // lbltext.text = gdata2;
   
}

 iphone实现文件的读写操作

iphone可以很容易的实现文件的读写,但是如果你没有使用苹果公司99美元开发者sdk的话,你利用破解打出来的api包,安装到手机上不能把文件写入手机.下面是我实现读写的代码:

#import "managerfile.h"

@implementation managerfile

-(void)writefile:(nsstring *)file 
{ 
  //创建文件管理器 
  nsfilemanager *filemanager = [nsfilemanager defaultmanager]; 
  //获取路径 
  //参数nsdocumentdirectory要获取那种路径 
  nsarray *paths = nssearchpathfordirectoriesindomains(nsdocumentdirectory, nsuserdomainmask, yes); 
  nsstring *documentsdirectory = [paths objectatindex:0];//去处需要的路径  
  //更改到待操作的目录下 
  [filemanager changecurrentdirectorypath:[documentsdirectory stringbyexpandingtildeinpath]]; 
  //创建文件filename文件名称，contents文件的内容，如果开始没有内容可以设置为nil，attributes文件的属性，初始为nil 
  //获取文件路径 
  [filemanager removeitematpath:@"username" error:nil]; 
  nsstring *path = [documentsdirectory stringbyappendingpathcomponent:@"username"]; 
  //创建数据缓冲 
  nsmutabledata *writer = [[nsmutabledata alloc] init]; 
  //将字符串添加到缓冲中 
  [writer appenddata:[file datausingencoding:nsutf8stringencoding]]; 
  //将其他数据添加到缓冲中 
  //将缓冲的数据写入到文件中 
  [writer writetofile:path atomically:yes]; 
  [writer release]; 
} 
-(nsstring *)readfile 
{ 
  //创建文件管理器 
  nsfilemanager *filemanager = [nsfilemanager defaultmanager]; 
  //获取路径 
  //参数nsdocumentdirectory要获取那种路径 
  nsarray *paths = nssearchpathfordirectoriesindomains(nsdocumentdirectory, nsuserdomainmask, yes); 
  nsstring *documentsdirectory = [paths objectatindex:0];//去处需要的路径  
  //更改到待操作的目录下 
  [filemanager changecurrentdirectorypath:[documentsdirectory stringbyexpandingtildeinpath]]; 
  //获取文件路径 
  nsstring *path = [documentsdirectory stringbyappendingpathcomponent:@"username"]; 
  nsdata *reader = [nsdata datawithcontentsoffile:path]; 
  return [[nsstring alloc] initwithdata:reader 
                 encoding:nsutf8stringencoding]; 
} 
@end

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