Android SQLite native NDK connector

Java classes with abstract interface layers to provide a simple, easy-to-use Java interface to the NDK library (may be adapted for other Java environments).

With a simple test Android app included.

Based on: liteglue / Android-sqlite-connector

by Christopher J. Brody aka Chris Brody mailto: chris.brody+brodybits@gmail.com

with some complex API response type enhancements by Luis Silva of OutSystems (luis dot silva at outsystems dot com)

License: UNLICENSE (public domain).

Dependencies

Included:

TBD

Not included

Android NDK library JAR build, from this for example: brodybits / android-sqlite-ndk-native-driver

Alternative native library builds

TBD

Installation

Include the following in your libs directory:

• NDK JAR library
• sqlite-native-ndk-connector.jar, which is built by simply issuing the make command in this project

Testing

There is a simple test project in the Android-SQLiteConnectorTest subdirectory. To test:

• Use the make command to build the JAR
• Build the NDK JAR
• cd Android-SQLiteConnectorTest
• Install the JAR files into the libs subdirectory of Android-SQLiteConnectorTest
• Use a tool such as Android Studio to build and run (import is needed for newer versions of Android Studio)

Sample API Usage

IMPORTANT: Most of the methods described here will throw java.sql.SQLException if the sqlite library reports an error or if they detect a problem with the usage.

First step

Import io.liteglue package:

import io.liteglue.*;

Get a SQLiteConnector (factory) instance:

SQLiteConnector myconnector = new SQLiteConnector();

Open a database

File dbfile = new File(getFilesDir(), "my.db");

SQLiteConnection mydbc = myconnector.newSQLiteConnection(dbfile.getAbsolutePath(),
    SQLiteOpenFlags.READWRITE | SQLiteOpenFlags.CREATE);

Prepare and run a simple statement (with no parameters)

SQLiteStatement mystatement = mydbc.prepareStatement("CREATE TABLE IF NOT EXISTS mytable (text1 TEXT, num1 INTEGER, num2 INTEGER, real1 REAL)");
mystatement.step();
mystatement.dispose();

IMPORTANT: Whenever SQLiteConnection.prepareStatement() successfully returns a SQLiteStatement, it must be cleaned up using its dispose() method.

Prepare and run a statement with parameter values

SQLiteStatement mystatement = mydbc.prepareStatement("INSERT INTO mytable (text1, num1, num2, real1) VALUES (?,?,?,?)");

mystatement.bindTextNativeString(1, "test");
mystatement.bindInteger(2, 10100);
mystatement.bindLong(3, 0x1230000abcdL);
mystatement.bindDouble(4, 123456.789);

mystatement.step();
mystatement.dispose();

SELECT data and get row result(s)

SQLiteStatement mystatement = mydbc.prepareStatement("SELECT * FROM mytable;");

boolean keep_going = mystatement.step();
while (keep_going) {
    int colcount = colcount = mystatement.getColumnCount();
    android.util.Log.e("MySQLiteApp", "Row with " + colcount + " columns");

    for (int i=0; i<colcount; ++i) {
        int coltype = mystatement.getColumnType(i);
        switch(coltype) {
        case SQLColumnType.INTEGER:
            android.util.Log.e("MySQLiteApp",
                "Col " + i + " type: INTEGER (long) value: 0x" +
                    java.lang.Long.toHexString(mystatement.getColumnLong(i)));
            break;

        case SQLColumnType.REAL:
            android.util.Log.e("MySQLiteApp",
                "Col " + i + " type: REAL value: " + mystatement.getColumnDouble(i));
            break;

        case SQLColumnType.NULL:
            android.util.Log.e("MySQLiteApp", "Col " + i + " type: NULL (no value)");
            break;

        default:
            android.util.Log.e("MySQLiteApp",
                "Col " + i + " type: " + ((coltype == SQLColumnType.BLOB) ? "BLOB" : "TEXT") +
                    " value: " + mystatement.getColumnTextNativeString(i));
            break;
        }
    }
    keep_going = mystatement.step();
}
mystatement.dispose();

Close the database connection

mydbc.dispose();

Internals

• Multiple layers with abstract interfaces to make it easier to replace the lower-level SQLiteGlue native database interface