【iOS】第03講 檔案讀寫/NSArray/NSData/NSFileManager/NSFileHandle
一、沙盒
模擬器上的沙盒目錄路徑
~/Library/Application Support/iPhone Simulator/6.0/Applications
獲取沙盒的目錄路徑
//NSHomeDirectory : 獲取沙盒的目錄路徑
NSString *homePath =NSHomeDirectory
NSLog(@"沙盒目錄：%@",homePath);
NSString *docPath1 = [NSStringstringWithFormat:@"%@/Documents",homePath];
NSString *docPath2 = [homePathstringByAppendingFormat:@"/Documents"];
NSLog(@"docPath1=%@,docPath2=%@"
二、檔案管理
2.1 NSString處理路徑
//NSString處理路徑
NSString *path =@"/Users/apple/file.text";
//1.獲取路徑的組成部分結果：（"/","Users","apple","file.text")
NSArray *components = [pathpathComponents];
//2.路徑的最後一個組成部分結果：file.text
NSString *lastName = [pathlastPathComponent];
//3.追加檔案或目錄結果：/Users/apple/file.text/app.text
NSString *filePath = [pathstringByAppendingString:@"app.text"];
//4.刪除最後的組成部分/副檔名
NSString *deletePath = [pathstringByDeletingLastPathComponent];
NSString *deleteExt = [pathstringByDeletingPathExtension];
//5.獲取副檔名/追加副檔名
NSString *ext = [pathpathExtension];
NSString *extPath = [pathstringByAppendingPathExtension:@"jpg"];
2.2 NSData資料處理
NSData是一種對資料的抽象
任何資料都可以通過NSData來儲存，NSMutableData是可變的，繼承於NSData
2.3 NSFileManager
NSFileManager主要對檔案進行管理，主要功能：
NSFileManager管理檔案的常用方法
//NSHomeDirectory : 獲取沙盒的目錄路徑
NSString *homePath =NSHomeDirectory();
NSLog(@"沙盒目錄：%@",homePath);
//1.建立一個檔案並寫入資料
NSString* filePath = [homePathstringByAppendingPathComponent:@"Documents/1.jpg"];
//NSFileManager 只能有一個例項物件，不能用alloc建立
NSFileManager* fileManager = [NSFileManagerdefaultManager];
BOOL result = [fileManagercreateFileAtPath:filePathcontents:nilattributes:nil];
if(result)
NSLog(@"file create success");
else
NSLog(@"file create fail");
//2.建立資料夾
filePath = [homePath stringByAppendingPathComponent:@"Documents/model/Smile/pic/01"];
NSLog(@"%@",filePath);
NSError *error;
result = [fileManager createDirectoryAtPath:filePathwithIntermediateDirectories:YESattributes:nilerror:&error];
if(result)
NSLog(@"file dir create success");
else
NSLog(@"file dir create fail");
//3.讀取檔案中的資料
filePath = [homePath stringByAppendingPathComponent:@"Documents/1.jpg"];
NSData *data = [fileManagercontentsAtPath:filePath];
NSString *string = [[NSStringalloc] initWithData:dataencoding:NSUTF8StringEncoding];
NSLog(@"%@",string);
//4.移動檔案
NSString* targetPath = [homePathstringByAppendingPathComponent:@"Documents/model/Smile/pic/01/1.jpg"];
result = [fileManager moveItemAtPath:filePathtoPath:targetPath error:nil];
if(result)
NSLog(@"file move success");
//5.複製檔案
result = [fileManager copyItemAtPath:targetPathtoPath:filePath error:nil];
if(result)
NSLog(@"file copy success");
//6.刪除檔案
BOOL fileExist = [fileManagerfileExistsAtPath:filePath];
if(fileExist)
{
result = [fileManager removeItemAtPath:filePatherror:nil];
if(result)
NSLog(@"file remove success");
}
//7.獲取檔案大小
NSDictionary* fileAttr = [fileManagerattributesOfItemAtPath:targetPatherror:nil];
NSLog(@"%@",fileAttr);
NSNumber *fileSize = [fileAttrobjectForKey:NSFileSize];
int sizeValue = [fileSizeintValue];
NSLog(@"檔案大小%d",sizeValue);
2.4 寫檔案
陣列NSArray、字典NSDictionary、字串NSString、NSData 都是容納資料的
NSArray、NSDictionary中只能
存入NSNumber、NSString、NSData、NSDate、NSArray、NSDictionary
才能寫入檔案，寫入後以xml方式儲存
它們都有一個writeToFile方法將資料寫入檔案
//NSString 讀寫檔案
filePath = [homePath stringByAppendingPathComponent:@"Documents/file.text"];
NSString *s =@"Hello iOS";
[s writeToFile:filePathatomically:YESencoding:NSUTF8StringEncodingerror:nil];
NSString *fileString = [NSStringstringWithContentsOfFile:filePathencoding:NSUTF8StringEncodingerror:nil];
NSLog(@"%@",fileString);
//NSData 讀寫檔案
NSData *data = [[NSDataalloc] initWithContentsOfFile:filePath];
fileString = [[NSStringalloc] initWithData:dataencoding:NSUTF8StringEncoding];
NSLog(@"%@",fileString);
[data writeToFile:filePathatomically:YES];
//NSArray 讀寫檔案
filePath = [homePath stringByAppendingPathComponent:@"Documents/array.plist"];
NSString *s1 =@"voron";
NSString *s2 =@"lisa";
NSArray *array = [[NSArrayalloc] initWithObjects:s1,s2,nil];
result = [array writeToFile:filePathatomically:YES];
if(result)
NSLog(@"NSArray write to file success");
NSArray* readArray = [[NSArrayalloc] initWithContentsOfFile:filePath];
for(NSString *sin readArray)
NSLog(@"s=%@",s);
//NSDictionary 讀寫檔案
NSDictionary *dict =@{
@"name":@"jack",
@"birth":[NSDatedate],
@"age":@22
};
filePath = [homePath stringByAppendingPathComponent:@"Documents/dict.plist"];
result = [dict writeToFile:filePathatomically:YES];
NSDictionary *readDict = [NSDictionarydictionaryWithContentsOfFile:filePath];
NSLog(@"%@",readDict);
2.5 NSFileHandle NSFileHandle主要是對檔案內容進行讀取和寫入操作 不能建立檔案
//NSFileHandle
//1.追加寫入資料
//建立一個寫入的FileHandle物件
NSFileHandle *writeHandle = [NSFileHandlefileHandleForWritingAtPath:filePath];
[writeHandle seekToEndOfFile];
NSString *appendString =@"appending data";
NSData* data = [appendStringdataUsingEncoding:NSUTF8StringEncoding];
[writeHandle writeData:data];
[writeHandle closeFile];
//2.定位讀取
NSFileHandle *readHandle = [NSFileHandlefileHandleForReadingAtPath:filePath];
//獲得檔案長度
NSDictionary* fileAttr = [fileManagerattributesOfItemAtPath:filePatherror:nil];
NSNumber *fileSize = [fileAttrobjectForKey:NSFileSize];
unsignedlong long sizeValue = [fileSizelongLongValue];
//設定偏移量
[readHandle seekToFileOffset:sizeValue/2];
data = [readHandle readDataToEndOfFile];
NSString *dataString = [[NSStringalloc] initWithData:dataencoding:NSUTF8StringEncoding];
NSLog(@"%@",dataString);
三、檔案讀寫類和檔案管理類實現
3.1 File類
File.h
#ifndef File_h
#define File_h
enum FileType
{
FT_WriteOnly,
FT_ReadOnly,
FT_ReadWrite
};
class File
{
public:
File(const char* relPath,NSString* absolutePath);
virtual ~File();
void Open(FileType type);
void Write(const char* data,int size);
void Read(char*& data,int size);
void Close();
private:
NSFileHandle *fileHandle;
const char* relativePath;
NSString* absolutePath;
};
#endif /* File_h */
File.mm
#import <Foundation/Foundation.h>
#import "File.h"
File::File(const char* relPath,NSString* absPath)
:relativePath(relPath),
absolutePath(absPath)
{
//
}
File::~File()
{
//
}
void File::Open(FileType type)
{
if(FT_WriteOnly == type)
{
fileHandle = [NSFileHandle fileHandleForWritingAtPath:absolutePath];
[fileHandle seekToEndOfFile];
}
else if(FT_ReadOnly == type)
{
fileHandle = [NSFileHandle fileHandleForReadingAtPath:absolutePath];
}
else if(FT_ReadWrite == type)
{
fileHandle = [NSFileHandle fileHandleForUpdatingAtPath:absolutePath];
}
}
void File::Write(const char *data, int size)
{
NSData *data_ = [NSData dataWithBytes:data length:size];
[fileHandle writeData:data_];
}
void File::Read(char *&data, int size)
{
//
}
void File::Close()
{
[fileHandle closeFile];
}
3.2 FileManager類
FileManager.h
#ifndef FileManager_h
#define FileManager_h
#include <map>
#include "Singleton.h"
#include "File.h"
using std::map;
class FileManager : public Singleton<FileManager>
{
public:
FileManager();
virtual ~FileManager();
File* CreateFile(const char* relativePath);
private:
NSFileManager *fileManager;
NSString *mainPath;
map<const char*,File*> fileMap;
};
#endif /* FileManager_h */
FileManager.mm
#import <Foundation/Foundation.h>
#import "FileManager.h"
template<>
FileManager* Singleton<FileManager>::ms_pSingleton(0);
FileManager::FileManager()
{
fileManager = [NSFileManager defaultManager];
NSString *homePath = NSHomeDirectory();
mainPath = [homePath stringByAppendingPathComponent:@"Documents"];
}
FileManager::~FileManager()
{
}
File* FileManager::CreateFile(const char *relativePath)
{
NSString* relPath = [NSString stringWithUTF8String:relativePath];
NSString* relativePathWithoutLast = [relPath stringByDeletingLastPathComponent];
NSString* filePath = [mainPath stringByAppendingPathComponent:relativePathWithoutLast];
NSLog(@"%@",filePath);
BOOL fileExist = [fileManager fileExistsAtPath:filePath];
if(!fileExist)
{
BOOL result = [fileManager createDirectoryAtPath:filePath withIntermediateDirectories:YES attributes:nil error:nil];
if(result)
NSLog(@"file dir create success");
else
NSLog(@"file dir create fail");
}
filePath = [mainPath stringByAppendingPathComponent:relPath];
NSLog(@"%@",filePath);
fileExist = [fileManager fileExistsAtPath:filePath];
if(!fileExist)
{
BOOL result = [fileManager createFileAtPath:filePath contents:nil attributes:nil];
if(result)
{
NSLog(@"file create success");
File* file = new File(relativePath,filePath);
fileMap[relativePath] = file;
return file;
}
else
NSLog(@"file create fail");
}
else
{
if(fileMap.find(relativePath) != fileMap.end())
return fileMap[relativePath];
File* file = new File(relativePath,filePath);
fileMap[relativePath] = file;
return file;
}
return 0;
}