Saving Data on Android

Reading from external storage
Replace the existing 
return
 statement of the 
getNote
 function with the following 
code:
val
 note = Note(fileName, 
""
) 
// 1
 
if
 (isExternalStorageReadable()) { 
  
// 2
 
  FileInputStream(noteFile(fileName)).use { stream -> 
    
// 4
 
    
val
 text = stream.bufferedReader().use { 
      it.readText() 
    } 
    
// 5
 
    note.noteText = text 
  } 
} 
return
 note
Saving Data on Android
Chapter 1: Using Files
raywenderlich.com
30

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For the most part, the procedure here is the same as reading from the internal 
storage but with a small difference. Here’s how it works:
1. Ensure the external storage is readable.
2. Open and consume the 
FileInputStream
, with 
use
, as you did before.
3. Open a 
BufferedReader
 with 
use
 so that you can efficiently read the file.
4. Assign the text that was read to the file to 
note.noteText
 and return the 
note
.
The above code also relies on the following two functions:
fun
 
isExternalStorageWritable
()
: 
Boolean
 { 
  
return
 Environment.getExternalStorageState() == 
Environment.MEDIA_MOUNTED 
} 
 
fun
 
isExternalStorageReadable
()
: 
Boolean
 { 
  
return
 Environment.getExternalStorageState() 
in
 
      setOf(Environment.MEDIA_MOUNTED, 
Environment.MEDIA_MOUNTED_READ_ONLY) 
}
The 
isExternalStorageWritable
 function determines if the external storage is 
mounted and ready for read/write operations, whereas 
isExternalStorageReadable
 determines only if the storage is ready for reading.
After writing and reading files, you’re ready to add the capability to delete a file from 
external storage.