如何获取Android目录中的所有文件名？

Question

Im trying to list all the files in a particular folder of my android emulator and i keep getting null answer.

Heres my code:

File sdCardRoot = Environment.getExternalStorageDirectory();
File[] file= new File(sdCardRoot+"path");
for (File f : file.listFiles()) {
    if (f.isFile())
        String name = f.getName();

}

This doesnt seem to work dont know why.

Answer 1

I've split the function in two parts, first function gets all the files in the given path and the second function gets the filenames from the file array.

public File[] GetFiles(String DirectoryPath) {
    File f = new File(DirectoryPath);
    f.mkdirs();
    File[] file = f.listFiles();
    return file;
}

public ArrayList<String> getFileNames(File[] file){
    ArrayList<String> arrayFiles = new ArrayList<String>();
     if (file.length == 0)
            return null;
        else {
            for (int i=0; i<file.length; i++) 
                arrayFiles.add(file[i].getName());
        }

    return arrayFiles;
}

Answer 2

change

File[] file= new File(sdCardRoot+"path");

with

File[] file= new File(sdCardRoot, "path");

and make sure the directory path exits

Answer 3

Just Check this:

  List<File> files = getListFiles(new File("YOUR ROOT")); 
  private List<File> getListFiles(File parentDir) {
      ArrayList<File> inFiles = new ArrayList<File>();
      File[] files = parentDir.listFiles();
      for (File file : files) {
          if (file.isDirectory()) {
          inFiles.addAll(getListFiles(file));
      } else {
          if(file.getName().endsWith(".csv")) {
              inFiles.add(file);
          }
      }
}

return inFiles;

Answer 4

Since sdCardRoot is instance of File , sdCardRoot+"path" will return the same thing as sdCardRoot.toString() + "path" .

However, calling file.toString() returns file name, but not absolute path. You need to call sdCardRoot.getAbsolutePath() + "path" .

Also, make sure that you have allowed the emulator to use a certain amount of memory for external storage.