Implementing a File Picker in Android and copying the selected file to another location

STEP 1 – Use an Implicit Intent:

To choose a file from the device, you should use an implicit Intent

Intent chooseFile = new Intent(Intent.ACTION_GET_CONTENT);
chooseFile.setType("*/*");
chooseFile = Intent.createChooser(chooseFile, "Choose a file");
startActivityForResult(chooseFile, PICKFILE_RESULT_CODE);

STEP 2 – Get the absolute file path:

To get the file path from a Uri, first, try using

Uri uri = data.getData();
String src = uri.getPath();

where data is the Intent returned in onActivityResult().

If that doesn’t work, use the following method:

public String getPath(Uri uri) {

    String path = null;
    String[] projection = { MediaStore.Files.FileColumns.DATA };
    Cursor cursor = getContentResolver().query(uri, projection, null, null, null);

    if(cursor == null){
        path = uri.getPath()
    }
    else{
        cursor.moveToFirst();
        int column_index = cursor.getColumnIndexOrThrow(projection[0]);
        path = cursor.getString(column_index);
        cursor.close();
    }

    return ((path == null || path.isEmpty()) ? (uri.getPath()) : path);
}

At least one of these two methods should get you the correct, full path.

STEP 3 – Copy the file:

What you want, I believe, is to copy a file from one location to another.

To do this, it is necessary to have the absolute file path of both the source and destination locations.

First, get the absolute file path using either my getPath() method or uri.getPath():

String src = getPath(uri);    /* Method defined above. */

or

Uri uri = data.getData();
String src = uri.getPath();

Then, create two File objects as follows:

File source = new File(src);
String filename = uri.getLastPathSegment();
File destination = new File(Environment.getExternalStorageDirectory().getAbsolutePath() + "/CustomFolder/" + filename);

where CustomFolder is the directory on your external drive where you want to copy the file.

Then use the following method to copy a file from one place to another:

private void copy(File source, File destination) {

   FileChannel in = new FileInputStream(source).getChannel();
   FileChannel out = new FileOutputStream(destination).getChannel();

   try {
      in.transferTo(0, in.size(), out);
   } catch(Exception){
      // post to log
   } finally {
      if (in != null)
         in.close();
      if (out != null)
         out.close();
   }
}

Try this. This should work.

Note: Vis-a-vis Lukas’ answer – what he has done is use a method called openInputStream() that returns the content of a Uri, whether that Uri represents a file or a URL.

Another promising approach – the FileProvider:

There is one more way through which it is possible to get a file from another app. If an app shares its files through the FileProvider, then it is possible to get hold of a FileDescriptor object which holds specific information about this file.

To do this, use the following Intent:

Intent mRequestFileIntent = new Intent(Intent.ACTION_GET_CONTENT);
mRequestFileIntent.setType("*/*");
startActivityForResult(mRequestFileIntent, 0);

and in your onActivityResult():

@Override
public void onActivityResult(int requestCode, int resultCode,
        Intent returnIntent) {
    // If the selection didn't work
    if (resultCode != RESULT_OK) {
        // Exit without doing anything else
        return;
    } else {
        // Get the file's content URI from the incoming Intent
        Uri returnUri = returnIntent.getData();
        /*
         * Try to open the file for "read" access using the
         * returned URI. If the file isn't found, write to the
         * error log and return.
         */
        try {
            /*
             * Get the content resolver instance for this context, and use it
             * to get a ParcelFileDescriptor for the file.
             */
            mInputPFD = getContentResolver().openFileDescriptor(returnUri, "r");
        } catch (FileNotFoundException e) {
            e.printStackTrace();
            Log.e("MainActivity", "File not found.");
            return;
        }
        // Get a regular file descriptor for the file
        FileDescriptor fd = mInputPFD.getFileDescriptor();
        ...
    }
}

where mInputPFD is a ParcelFileDescriptor.

References:

1. Common Intents – File Storage.

2. FileChannel.

3. FileProvider.

4. Requesting a Shared File.