Question

Does anyone know of a complete choose file dialog? Maybe one where you can filter out all files except for ones with specific extensions?

I have not found anything lightweight enough to implement easily into one of my projects. The only other option seems to be using OI FileManager's open intents, but that requires the user already having the file manager installed.

I would be grateful if someone could point out a Dialog that would allow the user to browse folders and select a file, and return the path.

1
143
11/25/2016 3:01:24 PM

Accepted Answer

You just need to override onCreateDialog in an Activity.

//In an Activity
private String[] mFileList;
private File mPath = new File(Environment.getExternalStorageDirectory() + "//yourdir//");
private String mChosenFile;
private static final String FTYPE = ".txt";    
private static final int DIALOG_LOAD_FILE = 1000;

private void loadFileList() {
    try {
        mPath.mkdirs();
    }
    catch(SecurityException e) {
        Log.e(TAG, "unable to write on the sd card " + e.toString());
    }
    if(mPath.exists()) {
        FilenameFilter filter = new FilenameFilter() {

            @Override
            public boolean accept(File dir, String filename) {
                File sel = new File(dir, filename);
                return filename.contains(FTYPE) || sel.isDirectory();
            }

        };
        mFileList = mPath.list(filter);
    }
    else {
        mFileList= new String[0];
    }
}

protected Dialog onCreateDialog(int id) {
    Dialog dialog = null;
    AlertDialog.Builder builder = new Builder(this);

    switch(id) {
        case DIALOG_LOAD_FILE:
            builder.setTitle("Choose your file");
            if(mFileList == null) {
                Log.e(TAG, "Showing file picker before loading the file list");
                dialog = builder.create();
                return dialog;
            }
            builder.setItems(mFileList, new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int which) {
                    mChosenFile = mFileList[which];
                    //you can do stuff with the file here too
                }
            });
            break;
    }
    dialog = builder.show();
    return dialog;
}
182
10/1/2016 8:47:43 AM

Thanx schwiz for idea! Here is modified solution:

public class FileDialog {
    private static final String PARENT_DIR = "..";
    private final String TAG = getClass().getName();
    private String[] fileList;
    private File currentPath;
    public interface FileSelectedListener {
        void fileSelected(File file);
    }
    public interface DirectorySelectedListener {
        void directorySelected(File directory);
    }
    private ListenerList<FileSelectedListener> fileListenerList = new ListenerList<FileDialog.FileSelectedListener>();
    private ListenerList<DirectorySelectedListener> dirListenerList = new ListenerList<FileDialog.DirectorySelectedListener>();
    private final Activity activity;
    private boolean selectDirectoryOption;
    private String fileEndsWith;    

    /**
    * @param activity 
    * @param initialPath
    */
    public FileDialog(Activity activity, File initialPath) {
        this(activity, initialPath, null);
    }

    public FileDialog(Activity activity, File initialPath, String fileEndsWith) {
        this.activity = activity;
        setFileEndsWith(fileEndsWith);
        if (!initialPath.exists()) initialPath = Environment.getExternalStorageDirectory();
            loadFileList(initialPath);
    }

    /**
    * @return file dialog
    */
    public Dialog createFileDialog() {
        Dialog dialog = null;
        AlertDialog.Builder builder = new AlertDialog.Builder(activity);

        builder.setTitle(currentPath.getPath());
        if (selectDirectoryOption) {
            builder.setPositiveButton("Select directory", new OnClickListener() {
                public void onClick(DialogInterface dialog, int which) {
                    Log.d(TAG, currentPath.getPath());
                    fireDirectorySelectedEvent(currentPath);
                }
            });
        }

        builder.setItems(fileList, new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int which) {
                String fileChosen = fileList[which];
                File chosenFile = getChosenFile(fileChosen);
                if (chosenFile.isDirectory()) {
                    loadFileList(chosenFile);
                    dialog.cancel();
                    dialog.dismiss();
                    showDialog();
                } else fireFileSelectedEvent(chosenFile);
            }
        });

        dialog = builder.show();
        return dialog;
    }


    public void addFileListener(FileSelectedListener listener) {
        fileListenerList.add(listener);
    }

    public void removeFileListener(FileSelectedListener listener) {
        fileListenerList.remove(listener);
    }

    public void setSelectDirectoryOption(boolean selectDirectoryOption) {
        this.selectDirectoryOption = selectDirectoryOption;
    }

    public void addDirectoryListener(DirectorySelectedListener listener) {
        dirListenerList.add(listener);
    }

    public void removeDirectoryListener(DirectorySelectedListener listener) {
        dirListenerList.remove(listener);
    }

    /**
    * Show file dialog
    */
    public void showDialog() {
        createFileDialog().show();
    }

    private void fireFileSelectedEvent(final File file) {
        fileListenerList.fireEvent(new FireHandler<FileDialog.FileSelectedListener>() {
            public void fireEvent(FileSelectedListener listener) {
                listener.fileSelected(file);
            }
        });
    }

    private void fireDirectorySelectedEvent(final File directory) {
        dirListenerList.fireEvent(new FireHandler<FileDialog.DirectorySelectedListener>() {
            public void fireEvent(DirectorySelectedListener listener) {
                listener.directorySelected(directory);
            }
        });
    }

    private void loadFileList(File path) {
        this.currentPath = path;
        List<String> r = new ArrayList<String>();
        if (path.exists()) {
            if (path.getParentFile() != null) r.add(PARENT_DIR);
            FilenameFilter filter = new FilenameFilter() {
                public boolean accept(File dir, String filename) {
                    File sel = new File(dir, filename);
                    if (!sel.canRead()) return false;
                    if (selectDirectoryOption) return sel.isDirectory();
                    else {
                        boolean endsWith = fileEndsWith != null ? filename.toLowerCase().endsWith(fileEndsWith) : true;
                        return endsWith || sel.isDirectory();
                    }
                }
            };
            String[] fileList1 = path.list(filter);
            for (String file : fileList1) {
                r.add(file);
            }
        }
        fileList = (String[]) r.toArray(new String[]{});
    }

    private File getChosenFile(String fileChosen) {
        if (fileChosen.equals(PARENT_DIR)) return currentPath.getParentFile();
        else return new File(currentPath, fileChosen);
    }

    private void setFileEndsWith(String fileEndsWith) {
        this.fileEndsWith = fileEndsWith != null ? fileEndsWith.toLowerCase() : fileEndsWith;
    }
}

class ListenerList<L> {
    private List<L> listenerList = new ArrayList<L>();

    public interface FireHandler<L> {
        void fireEvent(L listener);
    }

    public void add(L listener) {
        listenerList.add(listener);
    }

    public void fireEvent(FireHandler<L> fireHandler) {
        List<L> copy = new ArrayList<L>(listenerList);
        for (L l : copy) {
            fireHandler.fireEvent(l);
        }
    }

    public void remove(L listener) {
        listenerList.remove(listener);
    }

    public List<L> getListenerList() {
        return listenerList;
    }
}

Use it on activity onCreate (directory selection option is commented):

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    File mPath = new File(Environment.getExternalStorageDirectory() + "//DIR//");
    fileDialog = new FileDialog(this, mPath, ".txt");
    fileDialog.addFileListener(new FileDialog.FileSelectedListener() {
        public void fileSelected(File file) {
            Log.d(getClass().getName(), "selected file " + file.toString());
        }
    });
    //fileDialog.addDirectoryListener(new FileDialog.DirectorySelectedListener() {
    //  public void directorySelected(File directory) {
    //      Log.d(getClass().getName(), "selected dir " + directory.toString());
    //  }
    //});
    //fileDialog.setSelectDirectoryOption(false);
    fileDialog.showDialog();
}

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