Save bitmap to location


Question

I am working on a function to download an image from a web server, display it on the screen, and if the user wishes to keep the image, save it on the SD card in a certain folder. Is there an easy way to take a bitmap and just save it to the SD card in a folder of my choice?

My issue is that I can download the image, display it on screen as a Bitmap. The only way I have been able to find to save an image to a particular folder is to use FileOutputStream, but that requires a byte array. I am not sure how to convert (if this is even the right way) from Bitmap to byte array, so I can use a FileOutputStream to write the data.

The other option I have is to use MediaStore :

MediaStore.Images.Media.insertImage(getContentResolver(), bm,
    barcodeNumber + ".jpg Card Image", barcodeNumber + ".jpg Card Image");

Which works fine to save to SD card, but does not allow you to customize the folder.

1
447
3/13/2013 4:32:08 PM

Accepted Answer

try (FileOutputStream out = new FileOutputStream(filename)) {
    bmp.compress(Bitmap.CompressFormat.PNG, 100, out); // bmp is your Bitmap instance
    // PNG is a lossless format, the compression factor (100) is ignored
} catch (IOException e) {
    e.printStackTrace();
}
884
9/10/2018 4:57:34 PM

You should use the Bitmap.compress() method to save a Bitmap as a file. It will compress (if the format used allows it) your picture and push it into an OutputStream.

Here is an example of a Bitmap instance obtained through getImageBitmap(myurl) that can be compressed as a JPEG with a compression rate of 85% :

// Assume block needs to be inside a Try/Catch block.
String path = Environment.getExternalStorageDirectory().toString();
OutputStream fOut = null;
Integer counter = 0;
File file = new File(path, "FitnessGirl"+counter+".jpg"); // the File to save , append increasing numeric counter to prevent files from getting overwritten.
fOut = new FileOutputStream(file);

Bitmap pictureBitmap = getImageBitmap(myurl); // obtaining the Bitmap
pictureBitmap.compress(Bitmap.CompressFormat.JPEG, 85, fOut); // saving the Bitmap to a file compressed as a JPEG with 85% compression rate
fOut.flush(); // Not really required
fOut.close(); // do not forget to close the stream

MediaStore.Images.Media.insertImage(getContentResolver(),file.getAbsolutePath(),file.getName(),file.getName());

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