Android context

Question

I 'm reading on how to write to internal storage, and found the following code methods on the Android Developer forum.

In both the the cases, I do not know how to get/invoke the "context"'s method.

I don't understand what the context variable is and how I can create one.

Say I want app read a file on start up.

What is context and how can I use it to achieve reading from storage.

File file = new File(context.getFilesDir(), filename);

    FileInputStream fis = context.openFileInput("Data.dat",
                                                 Context.MODE_PRIVATE);

    InputStreamReader isr = new InputStreamReader(fis);
    BufferedReader bufferedReader = new BufferedReader(isr);
    StringBuilder sb = new StringBuilder();
    String line;
    while ((line = bufferedReader.readLine()) != null) {
        sb.append(line);
    }

Answer 1

Android Developer site's Documentation about File reading from internal storage says...

To read a file from internal storage:

1. Call openFileInput() and pass it the name of the file to read. This returns a FileInputStream.
2. Read bytes from the file with read().
3. Then close the stream with close().

So, your code to read the file named Data.dat should be as below.

FileInputStream fis = context.openFileInput("Data.dat");
InputStreamReader isr = new InputStreamReader(fis);
BufferedReader bufferedReader = new BufferedReader(isr);
StringBuilder sb = new StringBuilder();
String line;
while ((line = bufferedReader.readLine()) != null) {
    sb.append(line);
}