IOS文件系统

/*
ios文件系统
当第一次启动app时，ios操作系统就为此app创建了一个文件系统，该文件系统下就默认有4个目录，分别是：
Documents: 存储用户在操作app时产生的数据，次目录下地数据可以通过iCloud进行同步

Library: 用户偏好设置数据，通常和此类NSUserDefaults搭配使用，此目录下地数据可以通过iCloud进行同步

tmp: 存放临时数据（缓存），此目录下地数据不会通过iCloud进行同步

app: 开发者不会操作此目录，通常是通过此类NSBundle类来获取包内资源，如工程素材
*/

//获取程序根目录
NSString *rootPath = NSHomeDirectory();

//获取程序根目录下的Documents
NSString *documentsPath = [rootPath stringByAppendingFormat:@"/%@",@"Documents"];
//或者
documentsPath = [rootPath stringByAppendingPathComponent:@"Documents"];

NSLog(@"documentsPath = %@",documentsPath);

//常用的获取documents目录方法
/*
<#NSSearchPathDirectory directory#> :指定了搜索的路径名称
<#NSSearchPathDomainMask domainMask#> :限定了文件的检索范围只在沙盒（sandbox）内部
<#BOOL expandTilde#> :决定了是否展开波浪线符号，展开后才是完整的路径，这个布尔值设为YES时才会产开路径

该方法返回的为一个数组，在iphone中由于只有一个唯一路径，所以直接取数组第一个元素即可
*/
documentsPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];

NSLog(@"documentsPath = %@",documentsPath);

//下载一个视频文件到Documents目录下地Video文件夹

//这里我们封装一个函数，使得这个函数返回的时Documents目录下想要的文件夹的路径

NSString *videoPath = [self creatDirInDocuments:@"Video"];
NSLog(@"videoPath = %@",videoPath);

if (videoPath != nil) {
NSFileManager *fileManager = [NSFileManager defaultManager];

NSString *videoString = @"http://v8.tv.cctv5.cctv.com/r5wbth/4d/e7/4de76971-63f4-4717-f28b-03d757a7704f/mp4h.mp4";
//截取videoString最后一个/后的字符串
NSString *fileVideo = [videoPath stringByAppendingPathComponent:[videoString lastPathComponent]];
//如果文件夹不存在该路径
if (![fileManager fileExistsAtPath:fileVideo])
{
//进行编码
//            [videoString stringByAddingPercentEscapesUsingEncoding:<#(NSStringEncoding)#>];
NSCharacterSet *characterSet = [NSCharacterSet URLQueryAllowedCharacterSet];

videoString = [videoString stringByAddingPercentEncodingWithAllowedCharacters:characterSet];
//我们的图片，视频，音频在网络中都是以二进制文件传输，所以这里我们拿到的是data
NSData *data = [NSData dataWithContentsOfURL:[NSURL URLWithString:videoString]];

if (data == nil) {
NSLog(@"网络不给力，请稍后在试");
}
else
{
//用单例类NSFileManager的对象，将文件写入本地
BOOL isSuccess = [fileManager createFileAtPath:fileVideo contents:data attributes:nil];
if (isSuccess) {
NSLog(@"视频下载成功");
}
else
{
NSLog(@"视频下载失败");
}

}
}
}

//字符串拼接，获取Library目录
NSString *libraryPath = [rootPath stringByAppendingPathComponent:@"Library"];
NSLog(@"libraryPath = %@",libraryPath);

//第二种
libraryPath = [NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, YES) objectAtIndex:0];
NSLog(@"libraryPath = %@",libraryPath);

//tmp
NSString *tmpString = NSTemporaryDirectory();
NSLog(@"tmpString = %@",tmpString);

NSArray *imgsArray = @[@"http://d.hiphotos.baidu.com/image/pic/item/6a63f6246b600c331c964cf21d4c510fd9f9a119.jpg",@"http://c.hiphotos.baidu.com/image/pic/item/023b5bb5c9ea15ce9c017233b1003af33a87b219.jpg",@"http://f.hiphotos.baidu.com/image/pic/item/e1fe9925bc315c60d916f9d58ab1cb134954770d.jpg",@"http://h.hiphotos.baidu.com/image/pic/item/30adcbef76094b366b2389d7a4cc7cd98d109d53.jpg",@"http://d.hiphotos.baidu.com/image/pic/item/b17eca8065380cd72aaf30d7a644ad3459828153.jpg"];

//下载一些图片，放在tmp目录下地Imgs文件夹下，如果有些图片已经下载了，那么不会继续下载
NSString *imgsTmpPath =[self creatDirInTmp:@"Imgs"];
if (imgsTmpPath != nil) {
NSLog(@"imgsTmpPath = %@",imgsTmpPath);
for (int i=0; i<imgsArray.count; i++) {
NSString *imgsString = [imgsArray[i] lastPathComponent];

//获得每张图片的路径
NSString *imgsPath = [imgsTmpPath stringByAppendingPathComponent:imgsString];

NSFileManager *fileManager = [NSFileManager defaultManager];
if (![fileManager fileExistsAtPath:imgsPath])
{
NSString *urlString = [imgsArray[i] stringByAddingPercentEncodingWithAllowedCharacters:[NSCharacterSet URLQueryAllowedCharacterSet]];
NSData *data = [NSData dataWithContentsOfURL:[NSURL URLWithString:urlString]];

if (data == nil) {
NSLog(@"网路有问题，请稍后在试");
}
else
{
BOOL isSuccess = [data writeToFile:imgsPath atomically:YES];
if (isSuccess) {
NSLog(@"图片下载成功");
}
else
{
NSLog(@"图片下载失败");
}
}
}

}
}

//将字符串写入本地
NSString *targetString = @"Hello guys";
BOOL flag = [targetString writeToFile:[imgsTmpPath stringByAppendingPathComponent:@"a.txt"] atomically:YES encoding:4 error:nil];
if (flag) {
NSLog(@"成功将字符串写入本地");
}
else
{
NSLog(@"将字符串写入本地失败");
}

//将数字写入本地文件
NSArray *array = @[@"都是",@"爱情",@"惹得",@"祸"];
flag = [array writeToFile:[imgsTmpPath stringByAppendingPathComponent:@"array.txt"] atomically:YES];
if (flag) {
NSLog(@"成功将数组写入本地");
}
else
{
NSLog(@"将数组写入本地失败");
}

//将字典写入本地
NSDictionary *dictionary = @{@"name":@"Rick",@"age":@"25",@"address":@"GZ"};
flag = [dictionary writeToFile:[imgsTmpPath stringByAppendingPathComponent:@"dic.txt"] atomically:YES];
if (flag) {
NSLog(@"成功将地址写入本地");
}
else
{
NSLog(@"将地址写入本地失败");
}

//计算文件大小
//获得将要计算的文件夹
NSFileManager *fileManager = [NSFileManager defaultManager];

//获得imgs目录下文件名组成的数组
NSArray *imgsFileArray = [fileManager subpathsAtPath:imgsTmpPath];

NSLog(@"imgsFileArray = %@",imgsFileArray);

CGFloat count = 0;

for (NSString *ele in imgsFileArray) {
NSData *data = [NSData dataWithContentsOfFile:[imgsTmpPath stringByAppendingPathComponent:ele]];
count += data.length;
}

count = count/1024/1024;
NSLog(@"缓存文件的大小为%.2f M",count);

//删除文件
for (NSString *ele in imgsFileArray)
{
BOOL isSuccess = [fileManager removeItemAtPath:[imgsTmpPath stringByAppendingPathComponent:ele] error:nil];
if (isSuccess) {
NSLog(@"删除成功");
}
else
{
NSLog(@"删除失败");
}
}

//app包，获取包内图片，显示在UI
NSBundle *bundle = [NSBundle mainBundle];
NSLog(@"bundle = %@",bundle);

NSString *imgPath = [bundle pathForResource:@"023b5bb5c9ea15ce9c017233b1003af33a87b219" ofType:@".jpg"];

NSData *data = [NSData dataWithContentsOfFile:imgPath];

NSLog(@"data = %@",data);

self.imageview.image = [UIImage imageWithData:data];

}

-(NSString *)creatDirInDocuments:(NSString *)dirName
{
//获得Documents文件路径
NSString *documentsPath =[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];

//拼接成我们想要文件的路径的字符串
NSString *dirDocuments = [documentsPath stringByAppendingPathComponent:dirName];

//获取NSFileManager 单例类，用于文件操作
NSFileManager *fileManager = [NSFileManager defaultManager];

//判断本地是否存在某个文件或文件夹
BOOL isExist = [fileManager fileExistsAtPath:dirDocuments];
if (!isExist)
{
//创建文件夹
NSError *error;
BOOL isSuccess = [fileManager createDirectoryAtPath:dirDocuments withIntermediateDirectories:YES attributes:nil error:&error];
if (!isSuccess) {
//如果文件创建失败，将打印错误的信息
NSLog(@"error = %@",error.debugDescription);
dirDocuments = nil;
}
}
return dirDocuments;

}

-(NSString *)creatDirInTmp:(NSString *)dirname
{
NSString *tmp = NSTemporaryDirectory();

//想要文件的路劲
NSString *dirPath = [tmp stringByAppendingPathComponent:dirname];

NSFileManager *fileManager = [NSFileManager defaultManager];

if (![fileManager fileExistsAtPath:dirPath])
{
NSError *error;
BOOL isSuccess = [fileManager createDirectoryAtPath:dirPath withIntermediateDirectories:YES attributes:nil error:&error];
if (!isSuccess) {
dirPath = nil;
NSLog(@"error = %@",error.debugDescription);
}
}
return dirPath;
}