Content Provider in Android
ContentProvider are used to provide data from an
application to another. ContentProvider do not store the data but provide the
interface for other applications to access the data.
The following example will use an existing
context provider from "Contacts".
Create contacts on your emulator
For this example we need a few maintained
contacts. Select the home menu and then the menu entry "Contacts" to create contacts.
Press Menu and select "New Contact".
As a result you should have a few new
contacts.
Using the Contact Content Provider
Create a new Android project
"com.android.contentprovider" with the activity "ContactsView".
Rename the id of the existing TextView from the
example wizard to "contactview". Delete the default text. Also change the
layout_height to "fill_parent".
The resulting main.xml should look like the
following.
<?xml
version="1.0"
encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="@+id/contactview"
/>
</LinearLayout>
Access to the contact content provider requires a
certain permission as not all applications should have access to
the contact information. Open the
AndroidManifest.xml, and select the
Permissions tab. On that tab click
the "Add" button, and select "Uses Permission". From the drop-down
list select the entry "android.permission.READ_CONTACTS".
Change the coding of the activity.
package
com.android.contentprovider;
import
android.app.Activity;
import
android.database.Cursor;
import android.net.Uri;
import
android.os.Bundle;
import
android.provider.ContactsContract;
import
android.widget.TextView;
public
class ContactsView
extends Activity {
/** Called when the activity is first created. */
@Override
public
void onCreate(Bundle
savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
TextView contactView =
(TextView) findViewById(R.id.contactview);
Cursor cursor =
getContacts();
while
(cursor.moveToNext())
{
String displayName = cursor.getString(cursor
.getColumnIndex(ContactsContract.Data.DISPLAY_NAME));
contactView.append("Name: ");
contactView.append(displayName);
contactView.append("\n");
}
}
private Cursor getContacts() {
// Run query
Uri uri = ContactsContract.Contacts.CONTENT_URI;
String[] projection =
new String[] {
ContactsContract.Contacts._ID,
ContactsContract.Contacts.DISPLAY_NAME };
String selection = ContactsContract.Contacts.IN_VISIBLE_GROUP +
" = '"
+ ("1") +
"'";
String[] selectionArgs =
null;
String sortOrder = ContactsContract.Contacts.DISPLAY_NAME
+
" COLLATE LOCALIZED ASC";
return managedQuery(uri,
projection, selection, selectionArgs,
sortOrder);
}
}
Right click on the project
à Select Run As
à Android
Application.
When you run your application it will show you
all the names of the available contacts.
Thanks.
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