Android file copy

android, copy, file-io

Solution

If you are pulling the file in for use in your application what I suggest you do is read in the data then stuff the in memory data you have collected into some kind of reader (BufferedReader perhaps) so that you can then read the lines from there.

Here is an example of what I typically do:

// Assumption: I already have the file object I want to read
// Note: I'm not doing any error handling.
InputStream input = new FileInputStream(file);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];
int bytesRead = 0;
while( (bytesRead = input.read(buffer)) > 0){
    baos.write(buffer, 0, bytesRead);
}
StringReader stringReader = new StringReader( new String(baos.toByteArray()) );
BufferedReader bufferedReader = new BufferedReader( stringReader );
for(String line : bufferedReader.readLine()){
    // TODO: Handle each line appropriately or something
    Log.d("Reading Data Example", line);
}

Problem

I am finding that reading one line at a time from a text file on the SD card is rather slow. I imagine that it might be quicker if the file is in internal memory, so I want to copy files from the SD card to internal storage. The file copy examples I can find on the web seem to involve copying one byte at a time from an InputStream to an OutputStream or from a FileReader to a FileWriter. Is this really the quickest and most efficient method?

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