final SharedPreferences myPrefs = getSharedPreferences("cumstom_prefs", MODE_PRIVATE);
        final SharedPreferences.Editor editor = myPrefs.edit();
        editor.putInt("age", 15);
        editor.putString("name","小明");
        editor.apply();

    final String name = myPrefs.getString("name", "匿名");

        final String editContent = editText.getText().toString();
        FileOutputStream fos = null;
        try {
            fos = openFileOutput("my_file.txt", MODE_PRIVATE);
            fos.write(editContent.getBytes(Charset.forName("utf-8")));
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (fos != null) {
                    fos.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        BufferedReader br = null;
        try {
            FileInputStream fis = openFileInput("my_file.txt");
            br = new BufferedReader(new InputStreamReader(fis));
            String line = null;
            StringBuilder result = new StringBuilder();
            while (null != (line = br.readLine())) {
                result.append(line);
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if(br!=null){
                try {
                    br.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

public class MySqlite extends SQLiteOpenHelper {
    private static final int DATABASE_VERSION = 1;
    private static final String DATABASE_NAME = "my_database";
    private static final String TABLE_STUDENT = "table_student";
    private static final String COLUMN_ID = "id";
    private static final String COLUMN_NAME = "name";
    private static final String COLUMN_PHONE = "phone";

    public MySqlite(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        final String createTableStudent = "CREATE TABLE " + TABLE_STUDENT + " ("
                + COLUMN_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, "
                + COLUMN_NAME + " VARCHAR(20), "
                + COLUMN_PHONE + " VARCHAR(20)"
                + ")";
        db.execSQL(createTableStudent);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        if (oldVersion < newVersion) {
            String alterTableStudent = "ALTER TABLE " + TABLE_STUDENT + " ADD sex INTEGER";
            db.execSQL(alterTableStudent);
        }
    }
}

MySqlite mySqlite = new MySqlite(this);
final SQLiteDatabase writableDatabase = mySqlite.getWritableDatabase();