通過一個demo，我們來一起認識一下ios檔案系統。我們一起寫一個檔案管理器。可以查詢檔案，瀏覽目錄，並且可以識別檔案型別，開啟圖片，音訊，視訊等。
首先獲取路徑下的全部檔案路徑

- (void)viewDidLoad {
    [super viewDidLoad];

    NSString *path = self.path ? self.path:@"/Users/liuzixuan/Desktop/三階段（liu）";



    self.title = [path lastPathComponent];
    self.filePaths = [NSMutableArray array];
    NSArray
 
 *fileNames = [[NSFileManager defaultManager]contentsOfDirectoryAtPath:path error:nil];

    for (NSString *fileName in fileNames) {
        if ([fileName hasPrefix:@"."]) {
            continue;
        }
        NSLog(@"%@",fileName);
        NSString *filePath = [path stringByAppendingPathComponent:fileName];

        [self
 
.filePaths addObject:filePath];

    }


    self.navigationItem.rightBarButtonItem =  self.editButtonItem;
}

實現tableview

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    return self.filePaths.count;
}


- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath
 
 *)indexPath {
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"cell"];
    if (!cell) {
        cell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"cell"];
    }

    NSString *filePath = self.filePaths[indexPath.row];
    cell.textLabel.text = [filePath lastPathComponent];


    //判斷是否是資料夾
    if ([self isDirectoryOfPath:filePath]) {
        cell.imageView.image = [UIImage imageNamed:@"directory.png"];
    }else{
        cell.imageView.image = [UIImage imageNamed:@"other.png"];
    }
    return cell;
}

判斷是否為資料夾的 function

- (BOOL)isDirectoryOfPath:(NSString *)path{

    NSFileManager *fm = [NSFileManager defaultManager];

    BOOL isDir = NO;
    //方法返回值判斷的是檔案是否存在
    if ([fm fileExistsAtPath:path isDirectory:&isDir]&&isDir) {
        return YES;
    }

    return NO;
}

tableview的點選事件，並且識別檔案型別，實現對應的開啟方式

-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{

    NSString *filePath = self.filePaths[indexPath.row];

    //判斷是否是資料夾
    if ([self isDirectoryOfPath:filePath]) {

        FilesTableViewController *vc = [FilesTableViewController new];
        vc.path = filePath;
        [self.navigationController pushViewController:vc animated:YES];

    }else if ([filePath hasSuffix:@"mp4"]){

        AVPlayerViewController *vc = [AVPlayerViewController new];
        vc.player = [[AVPlayer alloc]initWithURL:[NSURL fileURLWithPath:filePath]];

        [vc.player play];

        [self.navigationController pushViewController:vc animated:YES];
    }else if ([filePath hasSuffix:@"jpg"]||[filePath hasSuffix:@"png"]){
        UIViewController *vc = [UIViewController new];
        vc.view.backgroundColor = [UIColor whiteColor];
        UIImageView *iv = [[UIImageView alloc]initWithFrame:self.view.bounds];
        [vc.view addSubview:iv];
        iv.image = [UIImage imageWithContentsOfFile:filePath];

        [self.navigationController pushViewController:vc animated:YES];

    }else if ([filePath hasSuffix:@"mp3"]){
        self.player = [[AVAudioPlayer alloc]initWithContentsOfURL:[NSURL fileURLWithPath:filePath] error:nil];
        [self.player play];
    }else if([filePath hasSuffix:@"rtf"]||[filePath hasSuffix:@"txt"]||[filePath hasSuffix:@".h"]||[filePath hasSuffix:@".m"]){


        UIViewController *vc = [UIViewController new];
        vc.view.backgroundColor = [UIColor whiteColor];
        UITextView *tv = [[UITextView alloc]initWithFrame:self.view.bounds];
        [vc.view addSubview:tv];
        tv.text = [NSString stringWithContentsOfFile:filePath encoding:NSUTF8StringEncoding error:nil];

        [self.navigationController pushViewController:vc animated:YES];




    }else{

        UIAlertController *ac = [UIAlertController alertControllerWithTitle:@"提示" message:@"目前版本暫不支援此格式，請期待下一版本！" preferredStyle:UIAlertControllerStyleAlert];

        UIAlertAction *action1 = [UIAlertAction actionWithTitle:@"確定" style:UIAlertActionStyleDefault handler:nil];

        [ac addAction:action1];


        [self presentViewController:ac animated:YES completion:nil];


    }
}

效果如下圖：