Android, create and populate SQLite database using InsertHelper and Assets

Question

I am new to Android development and would like to create and pre-populate a SQLite database using csv files from the Assets folder. I am using a database adapter class and in the onCreate method after creating the database I want to read the csv file fromt the assets folder and use it to insert rows using DatabaseUtils.InsertHelper.

import android.database.DatabaseUtils.InsertHelper; 
//... 

public void onCreate(SQLiteDatabase db) {
    db.execSQL(DATABASE_CREATE);

    // need to read the path csv data here containing columns "_id" and "path"

    try {
        InputStream is = getAssets().open("pathcsv"); 

        int size = is.available();

        // Read the entire asset into a local byte buffer.
        byte[] buffer = new byte[size];
        is.read(buffer);
        is.close();

        // Convert the buffer into a string.
        String text = new String(buffer);

    } catch (IOException e) {
        // Should never happen!
        throw new RuntimeException(e);
    }


    // Create a single InsertHelper to handle this set of insertions. 
    InsertHelper ih = new InsertHelper(db, "path_table"); 

    // Get the numeric indexes for each of the columns that we're updating 
    final int id_Column = ih.getColumnIndex("_id"); 
    final int path_Column = ih.getColumnIndex("path"); 

    while (moreRowsToInsert) { 
        // ... Create the data for this row (not shown) ... 

        // Get the InsertHelper ready to insert a single row 
        ih.prepareForInsert(); 

        // Add the data for each column 
        ih.bind(id_Column, idData); 
        ih.bind(path_Column, pathData); 

        // Insert the row into the database. 
        ih.execute(); 
    } 
} 
//... 


}

I am getting an eclipse error on the getAssets() line saying :

-The method getAssets() is undefined for the type DatabaseHelper

I can't seem to get context working at all, any help would be appreciated.

Update:

I should have included all of the code, which is :

private static class DatabaseHelper extends SQLiteOpenHelper {

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

    @Override
    public void onCreate(SQLiteDatabase db) {
           db.execSQL(PATH_TABLE_CREATE);
           try {
               InputStream is = getAssets().open("@string/path");  

    // the rest is as in my first post above....

If I add in a context as follows I get an error:

private static class DatabaseHelper extends SQLiteOpenHelper {

    private Context myContext; 

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

    @Override
    public void onCreate(SQLiteDatabase db, Context context) {
           db.execSQL(PATH_TABLE_CREATE);
           myContext = context; 
           try {
               InputStream is = myContext.getAssets().open("@string/path");  

    // the rest is as in my first post above....

The error I get is:

The method onCreate(SQLiteDatabase, Context) of type DQDbAdapter.DatabaseHelper must   override or implement a supertype method

Please can you help me to resolve this error. Thanks

score 4 · Answer 1 · edited May 23 '17 at 12:04

Do you need to populate the database in your app, or could you prepare it ahead of time? See here:

Populate Android Database From CSV file?

If you really want to do what you're trying to do in the code you posted, you could do something like this:

public class DatabaseHelper extends SQLiteOpenHelper {
...
    private Context context;

    DatabaseHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
        this.context = context;
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        ...
        context.getAssets()...
    }

Android, create and populate SQLite database using InsertHelper and Assets

1 Answers1