Write a Program to Create Grade Report Using Content Providers in Android

package com.example.mycontentprovider1;
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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 onClickAddRecord(View view) {
        // Adding a new record
        ContentValues values = new ContentValues();
 
        values.put(ReportProvider.NAME,
                ((EditText) findViewById(R.id.CourseName)).getText().toString());
 
        values.put(ReportProvider.GRADE,
                ((EditText) findViewById(R.id.txtGrade)).getText().toString());
 
        Uri uri = getContentResolver().insert(ReportProvider.CONTENT_URI,
                values);
 
        Toast.makeText(getBaseContext(), uri.toString(), Toast.LENGTH_LONG)
                .show();
    }
 
    public void onClickRetrieveRecords(View view) {
        // Retrieve all records
        String URL = "content://com.example.provider.Report/students";
        Uri var = Uri.parse(URL);
        Cursor c = managedQuery(var, null, null, null, "name");
        if (c.moveToFirst()) {
            do {
                Toast.makeText(
                        this,
                        c.getString(c.getColumnIndex(ReportProvider._ID))
                                + ", "
                                + c.getString(c
                                        .getColumnIndex(ReportProvider.NAME))
                                + ", "
                                + c.getString(c
                                        .getColumnIndex(ReportProvider.GRADE)),
                        Toast.LENGTH_SHORT).show();
            } while (c.moveToNext());
        }
    }
 
}

 
<pre lang="xml" cssfile="hk1_style">
package com.example.mycontentprovider1;
 
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 ReportProvider extends ContentProvider {
 
    static final String PROVIDER_NAME = "com.example.provider.Report";
    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> PROJECTION_MAP;
 
    static final int STUDENTS = 1;
    static final int STUDENT_ID = 2;
 
    static final UriMatcher uriMatcher;
    static {
        uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
        uriMatcher.addURI(PROVIDER_NAME, "students", STUDENTS);
        uriMatcher.addURI(PROVIDER_NAME, "students/#", STUDENT_ID);
    }
 
    private SQLiteDatabase db;
    static final String DATABASE_NAME = "College";
    static final String TABLE_NAME = "students";
    static final int DATABASE_VERSION = 1;
    static final String CREATE_DB_TABLE = " CREATE TABLE "
            + TABLE_NAME + " (_id INTEGER PRIMARY KEY AUTOINCREMENT, "
            + " name TEXT NOT NULL, " + " grade TEXT NOT NULL);";
 
    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 " + TABLE_NAME);
            onCreate(db);
        }
    }
 
    @Override
    public boolean onCreate() {
        Context context = getContext();
        DatabaseHelper dbHelper = new DatabaseHelper(context);
        /*
         * Create a write-able database and would create it if the database
         * dosen't exists already
         */
        db = dbHelper.getWritableDatabase();
        return (db == null) ? false : true;
    }
 
    @Override
    public Uri insert(Uri uri, ContentValues values) {
        /*
         * Add a new student
         */
        long rowID = db.insert(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(TABLE_NAME);
 
        switch (uriMatcher.match(uri)) {
        case STUDENTS:
            qb.setProjectionMap(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 == "") {
            // sort on the name of the courses
            sortOrder = NAME;
        }
        Cursor c = qb.query(db, projection, selection, selectionArgs, null,
                null, sortOrder);
 
        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(TABLE_NAME, selection, selectionArgs);
            break;
        case STUDENT_ID:
            String id = uri.getPathSegments().get(1);
            count = db.delete(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(TABLE_NAME, values, selection,
                    selectionArgs);
            break;
        case STUDENT_ID:
            count = db.update(
                    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 records
         */
        case STUDENTS:
            return "vnd.android.cursor.dir/vnd.example.students";
            /**
             * Get a particular record
             */
        case STUDENT_ID:
            return "vnd.android.cursor.item/vnd.example.students";
        default:
            throw new IllegalArgumentException("Unsupported URI: " + uri);
        }
    }
}