Working With Android SQLITE

Step 1 : Make and Android project named “MycontentProvider”.

Step 2: Paste the following code in MainActivity.java file.

import android.app.Activity;

import android.content.ContentValues;

import android.database.Cursor;

import android.net.Uri;

import android.os.Bundle;

import android.view.Menu;

import android.view.View;

import android.widget.EditText;

import android.widget.Toast;

 public class MainActivity extends Activity

 {

        @Override protected void onCreate(Bundle savedInstanceState)

        {

               super.onCreate(savedInstanceState);

               setContentView(R.layout.activity_main);

        }

        @Override public boolean onCreateOptionsMenu(Menu menu)

        {

               getMenuInflater().inflate(R.menu.main, menu);

               return true;

        }

        public void onClickAddName(View view)

        {

               // Add a new student record

               ContentValues values = new ContentValues();

               values.put(StudentsProvider.NAME, ((EditText)findViewById(R.id.txtName)).getText().toString());

               values.put(StudentsProvider.GRADE, ((EditText)findViewById(R.id.txtGrade)).getText().toString());

               Uri uri = getContentResolver().insert( StudentsProvider.CONTENT_URI, values);

               Toast.makeText(getBaseContext(), uri.toString(), Toast.LENGTH_LONG).show();

        }

        public void onClickRetrieveStudents(View view)

        {

               // Retrieve student records

               String URL = "content://com.example.provider.College/students";

               Uri students = Uri.parse(URL);

               Cursor c = managedQuery(students, null, null, null, "name");

               if (c.moveToFirst())

               {

                      do

                      {

                            Toast.makeText(this, c.getString(c.getColumnIndex(StudentsProvider._ID)) + ", " + c.getString(c.getColumnIndex( StudentsProvider.NAME)) + ", " + c.getString(c.getColumnIndex( StudentsProvider.GRADE)), Toast.LENGTH_SHORT).show();

                      }

                      while (c.moveToNext());

               }

        }

        

        }

Step 3 : Make another java class named “StudentsProvider”.

Step 4 : Paste the following code in StudentsProvider.java file.

import java.util.HashMap;

import android.content.ContentProvider;

import android.content.ContentUris;

import android.content.ContentValues;

import android.content.Context;

import android.content.UriMatcher;

import android.database.Cursor;

import android.database.SQLException;

import android.database.sqlite.SQLiteDatabase;

import android.database.sqlite.SQLiteOpenHelper;

import android.database.sqlite.SQLiteQueryBuilder;

import android.net.Uri;

import android.text.TextUtils;

 public class StudentsProvider extends ContentProvider

 {

        static final String PROVIDER_NAME = "com.example.provider.College";

        static final String URL = "content://" + PROVIDER_NAME + "/students";

        static final Uri CONTENT_URI = Uri.parse(URL);

        static final String _ID = "_id";

        static final String NAME = "name";

        static final String GRADE = "grade";

        private static HashMap<String, String> STUDENTS_PROJECTION_MAP;

        static final int STUDENTS = 1;

        static final int STUDENT_ID = 2;

        static final UriMatcher uriMatcher;

        private SQLiteDatabase db;

        static final String DATABASE_NAME = "College";

        static final String STUDENTS_TABLE_NAME = "students";

        static final int DATABASE_VERSION = 1;

        static final String CREATE_DB_TABLE = " CREATE TABLE " + STUDENTS_TABLE_NAME + " (_id INTEGER PRIMARY KEY AUTOINCREMENT, " + " name TEXT NOT NULL, " + " grade TEXT NOT NULL);";

        

        static

        {

        uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);

        uriMatcher.addURI(PROVIDER_NAME, "students", STUDENTS);

        uriMatcher.addURI(PROVIDER_NAME, "students/#", STUDENT_ID);

        }

        /** * Database specific constant declarations */

        /** * Helper class that actually creates and manages * the provider's underlying data repository. */

        private static class DatabaseHelper extends SQLiteOpenHelper

        {

               DatabaseHelper(Context context)

               {

                      super(context, DATABASE_NAME, null, DATABASE_VERSION);

               }

               @Override

               public void onCreate(SQLiteDatabase db)

               {

                      db.execSQL(CREATE_DB_TABLE);

               }

               @Override

               public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)

               {

                      db.execSQL("DROP TABLE IF EXISTS " + STUDENTS_TABLE_NAME);

                      onCreate(db);

               }

               

         }

        @Override

        public boolean onCreate()

        {

               Context context = getContext();

               DatabaseHelper dbHelper = new DatabaseHelper(context);

               /** * Create a write able database which will trigger its * creation if it doesn't already exist. */

               db = dbHelper.getWritableDatabase();

               return (db == null)? false:true;

        }

        @Override

        public Uri insert(Uri uri, ContentValues values)

        {

               /** * Add a new student record */

               long rowID = db.insert( STUDENTS_TABLE_NAME, "", values);

               /** * If record is added successfully */

               if (rowID > 0)

               {

                      Uri _uri = ContentUris.withAppendedId(CONTENT_URI, rowID);

                      getContext().getContentResolver().notifyChange(_uri, null); return _uri;

             

               }

               throw new SQLException("Failed to add a record into " + uri);

        }

        @Override

        public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder)

        {

               SQLiteQueryBuilder qb = new SQLiteQueryBuilder();

               qb.setTables(STUDENTS_TABLE_NAME);

               switch (uriMatcher.match(uri))

               {

               case STUDENTS: qb.setProjectionMap(STUDENTS_PROJECTION_MAP);

               break;

               case STUDENT_ID: qb.appendWhere( _ID + "=" + uri.getPathSegments().get(1));

               break;

               default:

                      throw new IllegalArgumentException("Unknown URI " + uri);

               }

               if (sortOrder == null || sortOrder == "")

               {

                      /** * By default sort on student names */

                      sortOrder = NAME;

               }

               Cursor c = qb.query(db, projection, selection, selectionArgs, null, null, sortOrder);

               /** * register to watch a content URI for changes */

               c.setNotificationUri(getContext().getContentResolver(), uri);

               return c;

               }

        @Override

        public int delete(Uri uri, String selection, String[] selectionArgs)

        {

               int count = 0; switch (uriMatcher.match(uri))

               {

               case STUDENTS: count = db.delete(STUDENTS_TABLE_NAME, selection, selectionArgs);

               break;

               case STUDENT_ID: String id = uri.getPathSegments().get(1);

               count = db.delete( STUDENTS_TABLE_NAME, _ID + " = " + id + (!TextUtils.isEmpty(selection) ? " AND (" + selection + ')' : ""), selectionArgs);

               break;

               default:

                      throw new IllegalArgumentException("Unknown URI " + uri);

               }

               getContext().getContentResolver().notifyChange(uri, null);

               return count;

        }

        @Override

        public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs)

        {

               int count = 0; switch (uriMatcher.match(uri))

               {

               case STUDENTS: count = db.update(STUDENTS_TABLE_NAME, values, selection, selectionArgs);

               break;

               case STUDENT_ID: count = db.update(STUDENTS_TABLE_NAME, values, _ID + " = " + uri.getPathSegments().get(1) + (!TextUtils.isEmpty(selection) ? " AND (" + selection + ')' : ""), selectionArgs);

               break;

               default:

                      throw new IllegalArgumentException("Unknown URI " + uri );

               }

               getContext().getContentResolver().notifyChange(uri, null);return count;

}

        @Override

        public String getType(Uri uri)

        {

               switch (uriMatcher.match(uri))

               {

               /** * Get all student records */

               case STUDENTS: return "vnd.android.cursor.dir/vnd.example.students";

               /** * Get a particular student */

               case STUDENT_ID: return "vnd.android.cursor.item/vnd.example.students";

               default: throw new IllegalArgumentException("Unsupported URI: " + uri);

               }

        }

        }

Step 5 : Paste the following code in activity_main.xml file.

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="fill_parent"

    android:layout_height="fill_parent"

    android:orientation="vertical" >

    <TextView

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:text="Name" />

    <EditText

        android:id="@+id/txtName"

        android:layout_width="fill_parent"

        android:layout_height="wrap_content" />

    <TextView

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:text="Grade" />

    <EditText

        android:id="@+id/txtGrade"

        android:layout_width="fill_parent"

        android:layout_height="wrap_content" />

    <Button

        android:id="@+id/btnAdd"

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:onClick="onClickAddName"

        android:text="Add Name" />

    <Button

        android:id="@+id/btnRetrieve"

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:onClick="onClickRetrieveStudents"

        android:text="Retrieve Students" />

</LinearLayout>

Step 6 : Pate the following code in strings.xml file.

<?xml version="1.0" encoding="utf-8"?>

<resources>

    <string name="app_name">mycontentprovider</string>

    <string name="hello_world">Hello world!</string>

    <string name="action_settings">Settings</string>

</resources>

Step 7 : Paste the following code in AndroidManifest.xml file.

<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

    package="com.example.mycontentprovider"

    android:versionCode="1"

    android:versionName="1.0" >

    <uses-sdk

        android:minSdkVersion="8"

        android:targetSdkVersion="17" />

    <application

        android:allowBackup="true"

        android:icon="@drawable/ic_launcher"

        android:label="@string/app_name"

        android:theme="@style/AppTheme" >

        <activity

            android:name="com.example.mycontentprovider.MainActivity"

            android:label="@string/app_name" >

            <intent-filter>

                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />

            </intent-filter>

        </activity>

        <provider

            android:name="StudentsProvider"

            android:authorities="com.example.provider.College" >

        </provider>

    </application>

</manifest>

Step 8 : Run your program.