android创建和删除文件夹

android如何创建和删除文件夹，网上说的各种方法都试过了

下面是代码

 //创建文件夹?????????????????????????????????????????
 void createFile(File onClickFile, String fileName) {
 File f = new File(onClickFile.getAbsolutePath() + File.separator + fileName + File.separator);
 if (f.exists()) {
 Toast.makeText(listActivity, "文件夹已存在", Toast.LENGTH_SHORT).show();
 } else {
 boolean bol = f.mkdir();
 System.out.println("f.getAbsolutePath()---------" + f.getAbsolutePath());
 if (bol) {
 Toast.makeText(listActivity, "文件夹创建成功", Toast.LENGTH_SHORT).show();
 } else {
 Toast.makeText(listActivity, "文件夹创建失败1", Toast.LENGTH_SHORT).show();
 }
 }
 }
//删除文件???????????????????????????????????????????
void deleteFile(File f) {
    System.out.println("f.getAbsolutePath()-----------" + f.getAbsolutePath());
    System.out.println("f.exists()-----------" + f.exists());
    System.out.println("f.canRead()-----------" + f.canRead());
    System.out.println("f.canWrite()-----------" + f.canWrite());
    System.out.println("f.isDirectory()-----------" + f.isDirectory());
    if (f.isFile()) {
        f.delete();
    } else if (f.isDirectory()) {
        File[] files = f.listFiles();
        if (files.length == 0) {
            f.delete();
        } else {
            for (int i = 0; i < files.length; i++) {
                deleteFile(files[i]);
            }
        }
    }
            //重新遍历父目录
    clickItem(parentFile);
    if (!f.exists()) {
        Toast.makeText(listActivity, "文件删除成功", Toast.LENGTH_SHORT).show();
    } else {
        Toast.makeText(listActivity, "文件删除失败", Toast.LENGTH_SHORT).show();
    }

}