目录和文件之间的Collections.sort

Question

I am using Arraylist of strings: ArrayList entries = new ArrayList(Arrays.asList(""));

and giving values dynamically. It may contain the names of Directories or Files.

I need to show entries in ListView such that, first all directories are shown in sort order then files in sort order.

Is this possible? if yes, any hint? Appreciate the help.. I am using

Collections.sort(entries); to sort my entries.

Answer 1

Use the 2 parameter version with a custom comparator. Compare it such that:

boolean firstFileIsDirectory = file1.isDirectory();
boolean secondFileIsDirectory = file2.isDirectory();
if(firstFileIsDirectory  && !secondFileIsDirectory){
    return -1;
}
if(!firstFileIsDirectory  && secondFileIsDirectory){
    return 1;
}
return String.compare(filename1, filename2);

Answer 2

I have done it. Logic used: separate the entries into two ArrayList. One having directories other files. Sort these two ArrayLists separately. Finally add these two to "entries". Here is the code:

private void sortEntries(String path){
    ArrayList<String> entriesDir = new ArrayList<String>(Arrays.asList(""));
    ArrayList<String> entriesFile = new ArrayList<String>(Arrays.asList(""));
    entriesDir.removeAll(entriesDir);
    entriesFile.removeAll(entriesFile);
    int fileCounter=0, dirCounter=0;
    path = path.equals("/") ? "" : path;
    for(int i=1;i<=entries.size();i++){
        if((new File(path+"/"+entries.get(i-1))).isFile()) entriesFile.add(fileCounter++, entries.get(i-1));
        else entriesDir.add(dirCounter++, entries.get(i-1));
    }
    Collections.sort(entriesDir,String.CASE_INSENSITIVE_ORDER);
    Collections.sort(entriesFile,String.CASE_INSENSITIVE_ORDER);
    entries.removeAll(entries);
    entries.addAll(entriesDir);
    entries.addAll(entriesFile);
}