How to make an Android application automatically create a certain file on installation?

Question

JavaScript

Hello.
There was a question. How can I make the application automatically create a certain file in a certain folder during installation? For example, sample.txt in the Android folder?
Thanks in advance! And sorry for the possibly stupid questions.
MainActivity:

import android.content.Intent;
import android.content.SharedPreferences;
import android.graphics.Typeface;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.support.v7.app.ActionBarActivity;
import android.text.method.LinkMovementMethod;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

import com.google.android.gms.ads.AdRequest;
import com.google.android.gms.ads.AdView;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;

public class MainActivity extends ActionBarActivity {
    private final static String FILENAME = "sample.txt"; // имя файла
    private EditText mEditText;

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        mEditText = (EditText) findViewById(R.id.editText);

        AdView mAdView = (AdView) findViewById(R.id.adView);
        AdRequest adRequest = new AdRequest.Builder().build();
        mAdView.loadAd(adRequest);

        TextView t2 = (TextView) findViewById(R.id.textView8);
        t2.setMovementMethod(LinkMovementMethod.getInstance());
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case R.id.action_save:
                saveFile(FILENAME);
                return true;
            default:
                return true;
            case R.id.action_settings:
                Intent intent = new Intent();
                intent.setClass(this, SettingsActivity.class);
                startActivity(intent);
                return true;
            case R.id.plus:
                intent = new Intent();
                intent.setClass(this, PlusActivity.class);
                startActivity(intent);
                return true;
        }
    }

    @Override
    public void onResume() {
        super.onResume();
        SharedPreferences prefs = PreferenceManager
                .getDefaultSharedPreferences(this);
        // читаем установленное значение из CheckBoxPreference
        if (prefs.getBoolean(getString(R.string.pref_openmode), false)) {
            openFile(FILENAME);

            // читаем стили текста из ListPreference
            String regular = prefs.getString(getString(R.string.pref_style), "");
            int typeface = Typeface.NORMAL;

            if (regular.contains("Bold"))
                typeface += Typeface.BOLD;

            if (regular.contains("Italic"))
                typeface += Typeface.ITALIC;

// меняем настройки в EditText
            mEditText.setTypeface(null, typeface);
        }

    }

    // Метод для открытия файла
    private void openFile(String fileName) {
        try {
            InputStream inputStream = openFileInput(fileName);

            if (inputStream != null) {
                InputStreamReader isr = new InputStreamReader(inputStream);
                BufferedReader reader = new BufferedReader(isr);
                String line;
                StringBuilder builder = new StringBuilder();

                while ((line = reader.readLine()) != null) {
                    builder.append(line + "\n");
                }

                inputStream.close();
                mEditText.setText(builder.toString());
            }
        } catch (Throwable t) {
            Toast.makeText(getApplicationContext(),
                    "Exception: " + t.toString(), Toast.LENGTH_LONG).show();
        }
    }

    // Метод для сохранения файла
    private void saveFile(String fileName) {
        try {
            OutputStream outputStream = openFileOutput(fileName, 0);
            OutputStreamWriter osw = new OutputStreamWriter(outputStream);
            osw.write(mEditText.getText().toString());
            osw.close();
        } catch (Throwable t) {
            Toast.makeText(getApplicationContext(),
                    "Exception: " + t.toString(), Toast.LENGTH_LONG).show();
        }
    }
}

Answer 1

You can do it easier, without a receiver, for this you need to extend Application and specify a new class in the manifest, so in onCreate of your Application you can create a file and if it already existed, do nothing with it. True, when deleting, it is not a fact that the file will be deleted, so it may be worth storing the creation date in the internal storage of your program to verify that the file is recent.

Answer 2

First you need to define a BroadcastReceiver that will respond to installation events, for this you can define the following intent-filter in the manifest:

<receiver android:name=".YourReceiver">
        <intent-filter>
            <action android:name="android.intent.action.PACKAGE_INSTALL" />
            <action android:name="android.intent.action.PACKAGE_ADDED" />
            <data android:scheme="package"/>
        </intent-filter>
</receiver>

Then you need to create a file in your BroadcastReceiver in the onReceive() method:

String content = "hello world";
String dir = Environment.getExternalStorageDirectory() + "/Android";
File file;
FileOutputStream outputStream;
try {
    file = new File(dir, "sample.txt");
    outputStream = new FileOutputStream(file);
    outputStream.write(content.getBytes());
    outputStream.close();
} catch (IOException e) {
    e.printStackTrace();
}