How to save image in android gallery

Question

I try to save the image into WathsappIMG but when I go to image gallery android I don't see the image and the image there into the directory can be seen from ES File Explorer

OutputStream output;
       // Find the SD Card path
        File filepath = Environment.getExternalStorageDirectory();

      // Create a new folder in SD Card
     File dir = new File(filepath.getAbsolutePath()
              + "/WhatSappIMG/");
        dir.mkdirs(); 

     // Retrieve the image from the res folder
        BitmapDrawable drawable = (BitmapDrawable) principal.getDrawable();
        Bitmap bitmap1 = drawable.getBitmap();

        // Create a name for the saved image
        File file = new File(dir, "Wallpaper.jpg" );

        try {

            output = new FileOutputStream(file);

            // Compress into png format image from 0% - 100%
            bitmap1.compress(Bitmap.CompressFormat.JPEG, 100, output);
            output.flush();
            output.close();

        }

        catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

Answer 1

the gallery don't displaying (necessarily) files from external storage.

this is a common mistake.

the gallery displays images stored on the media store provider

you can use this method to store image file on media store provider:

public static void addImageToGallery(final String filePath, final Context context) {

    ContentValues values = new ContentValues();

    values.put(Images.Media.DATE_TAKEN, System.currentTimeMillis());
    values.put(Images.Media.MIME_TYPE, "image/jpeg");
    values.put(MediaStore.MediaColumns.DATA, filePath);

    context.getContentResolver().insert(Images.Media.EXTERNAL_CONTENT_URI, values);
}