Searching subdirectories

Question

hi can anyone take a look at this code and tell me how to correct it. i am trying to search a directory and sub folders within it.
public ArrayList<File> arrfiles = new ArrayList<File>();
public File[] list =  null;      
public  ArrayList<File> listfiles(File folder){         
     try{
          list = folder.listFiles();
          for(int i = 0; i < list.length; i++){
               File file = list;
               if(file.isFile()){
                    arrfiles.add(file);
               else if(file.isDirectory()){
                    listfiles(file);
     catch(Exception e){
          System.out.print("Error" + e.toString());
     return arrfiles;
}problem is variable 'list' is overwritten every time there is a recursive call..                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           

Answer 1

For one thing, neither arrfiles nor list should be defined as class members outside of that method. That is not making for a good clean API, as you are making listfiles() depend on state before invoking it.
Instead, you should do it more like this (taking your existing code and just slightly modifying it):
// remove arrfiles and list variables...
public  ArrayList<File> listfiles(File folder){         
  ArrayList<File> arrfiles = new ArrayList<File>(); // declare and initialise here
  try{
    File[] list = folder.listFiles(); // declare and initialise here
    for(int i = 0; i < list.length; i++){
      File file = list;
if(file.isFile()){
arrfiles.add(file);
else if(file.isDirectory()){
arrfiles.addAll(listfiles(file)); // add returned list from recursive call into the list
catch(Exception e){
System.out.print("Error" + e.toString());
return arrfiles;