轉載:http://www.oschina.net/ios/302/ios-file-operations
1、在Documents裏創建目錄
創建一個叫test的目錄,先找到Documents的目錄,
- NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
- NSString *documentsDirectory = [paths objectAtIndex:0];
- NSLog(@"documentsDirectory%@",documentsDirectory);
- NSFileManager *fileManager = [NSFileManager defaultManager];
- NSString *testDirectory = [documentsDirectory stringByAppendingPathComponent:@"test"];
- // 創建目錄
- [fileManager createDirectoryAtPath:testDirectory withIntermediateDirectories:YES attributes:nil error:nil];
啓動程序,這時候目錄就創建了:
2、在test目錄下創建文件
創建文件怎麼辦呢?接着上面的代碼 testPath 要用stringByAppendingPathComponent拼接上你要生成的文件名,比如test00.txt。這樣才能在test下寫入文件。
testDirectory是上面代碼生成的路徑哦,不要忘了。我往test文件夾裏寫入三個文件,test00.txt ,test22.txt,text.33.txt。內容都是寫入內容,write String。
實現代碼如下:
- NSString *testPath = [testDirectory stringByAppendingPathComponent:@"test00.txt"];
- NSString *testPath2 = [testDirectory stringByAppendingPathComponent:@"test22.txt"];
- NSString *testPath3 = [testDirectory stringByAppendingPathComponent:@"test33.txt"];
- NSString *string = @"寫入內容,write String";
- [fileManager createFileAtPath:testPath contents:[string dataUsingEncoding:NSUTF8StringEncoding] attributes:nil];
- [fileManager createFileAtPath:testPath2 contents:[string dataUsingEncoding:NSUTF8StringEncoding] attributes:nil];
- [fileManager createFileAtPath:testPath3 contents:[string dataUsingEncoding:NSUTF8StringEncoding] attributes:nil];
在Documents目錄下創建就更簡單了,不用加test就ok了
3、獲取目錄列裏所有文件名
兩種方法獲取:subpathsOfDirectoryAtPath 和 subpathsAtPath
- NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
- NSString *documentsDirectory = [paths objectAtIndex:0];
- NSLog(@"documentsDirectory%@",documentsDirectory);
- NSFileManager *fileManage = [NSFileManager defaultManager];
- NSString *myDirectory = [documentsDirectory stringByAppendingPathComponent:@"test"];
- NSArray *file = [fileManage subpathsOfDirectoryAtPath: myDirectory error:nil];
- NSLog(@"%@",file);
- NSArray *files = [fileManage subpathsAtPath: myDirectory ];
- NSLog(@"%@",files);
獲取上面剛纔test文件夾裏的文件名
打印結果
2012-06-17 23:23:19.684 IosSandbox[947:f803] fileList:(
".DS_Store",
"test00.txt",
"test22.txt",
"test33.txt"
)
2012-06-17 23:23:19.686 IosSandbox[947:f803] fileLit(
".DS_Store",
"test00.txt",
"test22.txt",
"test33.txt"
)
兩個方法都可以,隱藏的文件也打印出來了。4、fileManager使用操作當前目錄
- //創建文件管理器
- NSFileManager *fileManager = [NSFileManager defaultManager];
- NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
- NSString *documentsDirectory = [paths objectAtIndex:0];
- //更改到待操作的目錄下
- [fileManager changeCurrentDirectoryPath:[documentsDirectory stringByExpandingTildeInPath]];
- //創建文件fileName文件名稱,contents文件的內容,如果開始沒有內容可以設置爲nil,attributes文件的屬性,初始爲nil
- NSString * fileName = @"testFileNSFileManager.txt";
- NSArray *array = [[NSArray alloc] initWithObjects:@"hello world",@"hello world1", @"hello world2",nil];
- [fileManager createFileAtPath:fileName contents:array attributes:nil];
changeCurrentDirectoryPath目錄更改到當前操作目錄時,做文件讀寫就很方便了,不用加上全路徑
5、刪除文件
接上面的代碼,remove就ok了。
- [fileManager removeItemAtPath:fileName error:nil];
用NSMutableData創建混合數據,然後寫到文件裏。並按數據的類型把數據讀出來
6.1寫入數據:- NSString * fileName = @"testFileNSFileManager.txt";
- NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
- NSString *documentsDirectory = [paths objectAtIndex:0];
- //獲取文件路徑
- NSString *path = [documentsDirectory stringByAppendingPathComponent:fileName];
- //待寫入的數據
- NSString *temp = @"nihao 世界";
- int dataInt = 1234;
- float dataFloat = 3.14f;
- //創建數據緩衝
- NSMutableData *writer = [[NSMutableData alloc] init];
- //將字符串添加到緩衝中
- [writer appendData:[temp dataUsingEncoding:NSUTF8StringEncoding]];
- //將其他數據添加到緩衝中
- [writer appendBytes:&dataInt length:sizeof(dataInt)];
- [writer appendBytes:&dataFloat length:sizeof(dataFloat)];
- //將緩衝的數據寫入到文件中
- [writer writeToFile:path atomically:YES];
我們看看數據怎麼樣了:
我們看到後面的是亂碼,那是中文被轉成了NSData後,還有int float的二進制
6.2讀取剛纔寫入的數據:
- //讀取數據:
- int intData;
- float floatData = 0.0;
- NSString *stringData;
- NSData *reader = [NSData dataWithContentsOfFile:path];
- stringData = [[NSString alloc] initWithData:[reader subdataWithRange:NSMakeRange(0, [temp length])]
- encoding:NSUTF8StringEncoding];
- [reader getBytes:&intData range:NSMakeRange([temp length], sizeof(intData))];
- [reader getBytes:&floatData range:NSMakeRange([temp length] + sizeof(intData), sizeof(floatData))];
- NSLog(@"stringData:%@ intData:%d floatData:%f", stringData, intData, floatData);
打印出來的結果:
2012-06-17 23:51:14.723 IosSandbox[1285:f803] stringData:nihao hello! intData:1234332 floatData:3.140000
這裏把寫入的漢字改成了 hello。因爲[temp length]算長度是,把中文算成一位了,出來的結果有誤。