BrowseForFolder.java

package org.limewire.ui.swing.util;

import com.sun.jna.Library;
import com.sun.jna.Native;
import com.sun.jna.Pointer;
import com.sun.jna.Structure;

/**
 * Spawns the BrowseForFolder dialog for Windows.
 *
 */
public final class BrowseForFolder {

    private Shell32 lib;
    private Shell32.BROWSEINFO info;

    //see http://msdn.microsoft.com/en-us/library/bb773205(VS.85).aspx 
    //for documentation on these flags and the BROWSEINFO struct
    public final static int BIF_RETURNONLYFSDIRS = 1;
    public final static int BIF_DONTGOBELOWDOMAIN = 2;
    public final static int BIF_STATUSTEXT = 4;
    public final static int BIF_RETURNFSANCESTORS = 8;
    public final static int BIF_EDITBOX = 16;
    public final static int BIF_VALIDATE = 32;
    public final static int BIF_NEWDIALOGSTYLE = 64;
    public final static int BIF_BROWSEINCLUDEURLS = 128;
    public final static int BIF_USENEWUI = 256;
    public final static int BIF_UAHINT = 512;
    public final static int BIF_NONEWFOLDERBUTTON = 1024;
    public final static int BIF_NOTRANSLATETARGETS = 2048;
    public final static int BIF_BROWSEFORCOMPUTER = 4096;
    public final static int BIF_BROWSEFORPRINTER = 8192;
    public final static int BIF_BROWSEINCLUDEFILES = 16384;
    public final static int BIF_SHAREABLE = 32768;

    /**
     * 
     * @param msg the message to show the user. Appears above the tree.
     * @param showEditBox true shows the edit box below the tree
     * @param allowNewFolder true allows users to create a new folder in this dialog
     */
    public BrowseForFolder(String msg, boolean showEditBox, boolean allowNewFolder){
        
        //initialize the struct
        lib = Shell32.INSTANCE;
        info = new Shell32.BROWSEINFO();
        info.lpszTitle = msg;
        
        int flags = showEditBox ? BIF_EDITBOX : 0;
        flags = flags | (allowNewFolder ? BIF_NEWDIALOGSTYLE : 0);
        
        //always hide recycle bin and see what other flags are set
        info.ulFlags = BIF_RETURNONLYFSDIRS | flags;
    }
    
    /**
     * Shows the widget.
     * @return a string containing the absolute path the user choose
     */
    public String showWidget(){
        Pointer ptr = lib.SHBrowseForFolder(info);
        byte[] path = new byte[1024];
        lib.SHGetPathFromIDList(ptr, path);
        return Native.toString(path);
    }

    //Creates an interface loads the shell32.dll library
    private interface Shell32 extends Library  {
        Shell32 INSTANCE = (Shell32)
        Native.loadLibrary("shell32", Shell32.class);

        //A Java version of the C++ struct used for this dialog
        public class BROWSEINFO extends Structure {
            public Pointer hwndOwner;
           public Pointer pidlRoot;
           public Pointer pszDisplayName;
           public String lpszTitle;
           public int ulFlags;
           public Pointer lpfn;
           public Pointer lParam;
           public int iImage;
        }
    
       //Method headers we will be calling from Java
       Pointer SHBrowseForFolder(BROWSEINFO info);
       Boolean SHGetPathFromIDList(Pointer idl, byte[] path);
    }
}