Android filechooser没有显示所有文件夹/文件但显示了一些

Question

为什么filechooser没有显示所有文件夹（文件夹和文件），但显示了一些文件/文件夹？

Android Manifest：

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

FileChooser类：

public class FileChooser extends ListActivity {
    private File directory;
    private FileArrayAdapter adapter;



    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        directory = new File("/sdcard/");
        fill(directory);
    }

    public void fill(File f){
        File[] dirs = f.listFiles();
        this.setTitle("Dir:"+f.getName());
        List<Option> dir = new ArrayList<Option>();
        List<Option> files = new ArrayList<Option>();
        try{
            for(File ff:dirs){
                if(ff.isDirectory()){
                    dir.add(new Option(ff.getName(),"[+]Pasta ",ff.getPath()));
                }else{
                    long size;
                    if(ff.length()>0){
                        size=ff.length()/1024;
                    }else{
                        size=ff.length();
                    }
                    files.add(new Option(ff.getName(),"Tamanho "+size+"kb",ff.getPath()));
                }

            }
        }catch (Exception e){}
        Collections.sort(dir);
        Collections.sort(files);
        dir.addAll(files);


        if(!f.getName().equalsIgnoreCase("")){
            dir.add(0,new Option("..","pasta anterior",f.getParent()));
        }


        adapter = new FileArrayAdapter(FileChooser.this,R.layout.activity_file_chooser,dir);
        this.setListAdapter(adapter);
    }
    protected void onListItemClick(ListView listView, View view, int position, long id){
        super.onListItemClick(listView,view,position,id);
        Option o = adapter.getItems(position);

        if(o.getData().equalsIgnoreCase("[+]Pasta ")||o.getData().equalsIgnoreCase("pasta anterior")){
            directory = new File((o.getPath()));
            fill(directory);
        }else{
            try {
                Bundle extras = getIntent().getExtras();
                String classname = extras.getString("class");
                Class<?> clazz = Class.forName(classname);
                Intent intent = new Intent(FileChooser.this, clazz);
                intent.putExtra("path", o.getPath());
                startActivity(intent);
            }catch (Exception e){
                Log.d(">>>>", String.valueOf(e));
            }
        }
    }
}

模拟器上的SDFOLDER

使用filebrowser apk

SDFOLDER或/ Storage / Emulated / on Emulator（空）

用我的apk

/ sys / kernel / on Emulator

用我的apk（工作正常！）