There are file explorer style apps that will open it. Or you could download Csv Viewer app from Play Store.

Blurb from it.

CSV File Viewer For Android | CSV Reader - view small and large-sized CSV files.

CSV Reader - Simple, fast, and powerful tool for reading csv files.

I am not associated with it.

Try OpenCSV - it will make your life easier.

First, add this package to your gradle dependencies as follows

implementation 'com.opencsv:opencsv:4.6'

Then you can either do

import com.opencsv.CSVReader;
import java.io.IOException;
import java.io.FileReader;


...

try {
    CSVReader reader = new CSVReader(new FileReader("yourfile.csv"));
    String[] nextLine;
    while ((nextLine = reader.readNext()) != null) {
        // nextLine[] is an array of values from the line
        System.out.println(nextLine[0] + nextLine[1] + "etc...");
    }
} catch (IOException e) {

}

or

CSVReader reader = new CSVReader(new FileReader("yourfile.csv"));
List myEntries = reader.readAll();

Edit after comment

try {
    File csvfile = new File(Environment.getExternalStorageDirectory() + "/csvfile.csv");
    CSVReader reader = new CSVReader(new FileReader(csvfile.getAbsolutePath()));
    String[] nextLine;
    while ((nextLine = reader.readNext()) != null) {
        // nextLine[] is an array of values from the line
        System.out.println(nextLine[0] + nextLine[1] + "etc...");
    }
} catch (Exception e) {
    e.printStackTrace();
    Toast.makeText(this, "The specified file was not found", Toast.LENGTH_SHORT).show();
}

If you want to package the .csv file with the application and have it install on the internal storage when the app installs, create an assets folder in your project src/main folder (e.g., c:\myapp\app\src\main\assets\), and put the .csv file in there, then reference it like this in your activity:

String csvfileString = this.getApplicationInfo().dataDir + File.separatorChar + "csvfile.csv"
File csvfile = new File(csvfileString);

I have something like this;

public final List<String[]> readCsv(Context context) {
  List<String[]> questionList = new ArrayList<String[]>();
  AssetManager assetManager = context.getAssets();

  try {
    InputStream csvStream = assetManager.open(CSV_PATH);
    InputStreamReader csvStreamReader = new InputStreamReader(csvStream);
    CSVReader csvReader = new CSVReader(csvStreamReader);
    String[] line;

    // throw away the header
    csvReader.readNext();

    while ((line = csvReader.readNext()) != null) {
      questionList.add(line);
    }
  } catch (IOException e) {
    e.printStackTrace();
  }
  return questionList;
}

You are indeed confused and mixing some things up. Let's go step by step.

STEP BY STEP, QUESTION BY QUESTION

1. A class and an activity are not the same. You can read about it here and here. To put it in an easy way:

   • A class is a Java form.
   • For each screen in your app you will have a different activity. Each of them might have more than one class.

2. Then, in Android, if you want to do any app (including the one which needs to read the .csv) you will need an activity, so that there is at least one screen in which the user can be. That is to say that the first thing you will need to do is to create an activity and add it to the manifest as the default activity (so that it appears together with the rest of apps). Do this (create activity), and then this (set it as default).

3. Now you should be able to try the app in an emulator or a physical device and see an empty screen that does nothing.

4. So far, so good. Now to the .csv reading problem. We will read the code as soon as the user enters the activity, when the activity is created (in the onCreate method). There should be a piece of code like the following one in your activity, otherwise, create it.

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}

5. Now we will proceed to read the csv inside the onCreate (you could also do it when the user presses a button, etc.). Note that one thing is reading it and the other one is creating visible UI lists with it. Here you can see how to read a csv file (either if you have it in the sd or if you pack it with the app).

EDIT. Let's deep deeper into this step (5). As stated in the answer I have referenced, you need to:

Add this package to your gradle dependencies as follows

implementation 'com.opencsv:opencsv:4.6'

And then modify the onCreate (or wherever you want to read the csv):

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

try {
// OPTION 1: if the file is in the sd
    File csvfile = new File(Environment.getExternalStorageDirectory() + "/csvfile.csv"); 
// END OF OPTION 1

// OPTION 2: pack the file with the app
/* "If you want to package the .csv file with the application and have it install on the internal storage when the app installs, create an assets folder in your project src/main folder (e.g., c:\myapp\app\src\main\assets\), and put the .csv file in there, then reference it like this in your activity:" (from the cited answer) */
String csvfileString = this.getApplicationInfo().dataDir + File.separatorChar + "csvfile.csv"
File csvfile = new File(csvfileString);
// END OF OPTION 2

    CSVReader reader = new CSVReader(new FileReader("csvfile.getAbsolutePath()"));
    String[] nextLine;
    while ((nextLine = reader.readNext()) != null) {
        // nextLine[] is an array of values from the line
        System.out.println(nextLine[0] + nextLine[1] + "etc...");
    }
} catch (Exception e) {
    e.printStackTrace();
    Toast.makeText(this, "The specified file was not found", Toast.LENGTH_SHORT).show();
}
}

FINALLY

Right, so this would be it. If you also wanted to represent this data in a list, a grid, etc., well, this is another question! However, just in case, you just need to use again the activity you created, but add the ListView to your layout and feed the list also in onCreate (for example). See a tutorial here.

There is a small app called aGrep which I use for such search on an old Android. It is open-source and works like "grep" but with an interface.

• User can specify file extension types e.g. csv, txt
• User can specify directory to search
• It can also read SDcard. etc

It has not been updated in a while, but does the job.

Repository: https://github.com/jiro-aqua/aGrep

CSV stands for Comma-Separated Values. Quite good explanation can be found at wiki: CSV. Since you're programming on Android platform consider using one of availible Java libraries such as OpenCSV or JavaCSV.