77.5 Reading the Content of a File

The exact steps required to read the content of a file hosted by a document provider will depend to a large extent on the type of the file. The steps to read lines from a text file, for example, differ from those for image or audio files.

An image file can be assigned to a Bitmap object by extracting the file descriptor from the Uri object and then decoding the image into a BitmapFactory instance. For example:

val pFileDescriptor = contentResolver.openFileDescriptor(uri, "r")

val fileDescriptor = pFileDescriptor.fileDescriptor

 

val image = BitmapFactory.decodeFileDescriptor(fileDescriptor)

 

pFileDescriptor.close()

 

val myImageView = ImageView(this)

myImageView.setImageBitmap(image)

Note that the file descriptor is opened in “r” mode. This indicates that the file is to be opened for reading. Other options are “w” for write access and “rwt” for read...