Hello !! Friends in this tutorial we are going to insert data and retrieve the data using our Own ContentProvider.
- Steps are as Follows :
- Create a new project and name it as “MyContentProvider”.
- Now your MainActivity.Java and activity_main.xml will be generated.
- Go to your activity_main.xml file and design the graphical layout for your display.
- Take two TextView and set its text as NAME and GRADE .
- Also take two EditText and place them below NAME and GRADE respectively.
- Also take two buttons and name it as Add Name and Retrive Students .
- The code for the activity_main.xml file is given below :
- The Layout will look as shown :
- Thus the window will look like as shown below :
- Now go to your MainActivity.Java file and write the Code for Add and Retrive button as shown below :
- Your MainActivity.Java file will look as shown below :
- Now create another class named StudentsProvider.Java and write the following code :
- So your coded window will look like as shown below :
- Now go to your AndroidManifest.xml file and write the following code inside the application :
- Your AndroidManifest.xml file will look as shown below :
- Now run your application and you will have the following Output :
- Now enter the name and grade and click on the add button and Your record will be added .
- Now when you will click on Retrive Students button you will get an toast message displaying the inserted student’s name grade and Id’s.
- Thus we have implemented our own ContentProvider .
[code language=”xml”]<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_height="wrap_content"
android:layout_width="fill_parent" />
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Grade" />
<EditText
android:id="@+id/txtGrade"
android:layout_height="wrap_content"
android:layout_width="fill_parent" />
<Button
android:text="Add Name"
android:id="@+id/btnAdd"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:onClick="onClickAddName" />
<Button
android:text="Retrieve Students"
android:id="@+id/btnRetrieve"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:onClick="onClickRetrieveStudents" />
</LinearLayout>
[/code]
[code language=”java”]public void onClickAddName(View view)
{
// Add a new student record
ContentValues values = new ContentValues();
//Add the NAME in the database:
values.put(StudentsProvider.NAME,
((EditText)findViewById(R.id.txtName)).getText().toString());
//Add the GRADE in the database:
values.put(StudentsProvider.GRADE,
((EditText)findViewById(R.id.txtGrade)).getText().toString());
//Insert the values in StudentsProvider :
Uri uri = getContentResolver().insert(
StudentsProvider.CONTENT_URI, values);
//Set the Toast message:
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
{
//Display the Id,Name,Grade on clicking the retrieve button :
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());
}
}
[/code]
[code language=”java”]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;
static
{
uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
uriMatcher.addURI(PROVIDER_NAME, "students", STUDENTS);
uriMatcher.addURI(PROVIDER_NAME, "students/#", STUDENT_ID);
}
/**
* Database specific constant declarations
*/
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);";
/**
* 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 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 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);
}
}
@Override
public Uri insert(Uri uri, ContentValues values) {
// TODO Auto-generated method stub
/*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 int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
// TODO Auto-generated method stub
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;
}
}
[/code]
[code language=”xml”]
<provider android:name="StudentsProvider"
android:authorities="com.example.provider.College">
</provider>
[/code]
//StudentsProvider is the name of the class and com.example.provider.College is the PROVIDER_NAME given in the StudentsProvider.Java class.