At last I concluded, it is ContentProvider which we need to use for database operation ..
ContentProviderDb.java
Content Providers
Content providers store and retrieve data and make it accessible to all applications. They're the only way to share data across applications;
- Yes content providers are mainly aimed to share data amount different application
- It can be also used inside our single application
- There is no worries of closing and locking of db
- It can be accessed from different activities, services and Thread. Anywhere that have context object
- I don't know is this a bad idea, I don't think so. Don't think it will reduce our data security. Our data can be accessed only with our AUTHORITY url
When a request is made via a ContentResolver the system inspects the authority of the given URI and passes the request to the content provider registered with the authority.
Now I'm trying to demonstrate the way how we can use ContentProvider in most simple way...ContentProviderDb.java
public class ContentProviderDb extends ContentProvider{
OurDatabaseHelper dbHelper ;
public static final String AUTHORITY = "ourContentProviderAuthorities";//specific for our our app, will be specified in maninfed
public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY);
@Override
public boolean onCreate() {
dbHelper = new OurDatabaseHelper(getContext());
return true;
}
@Override
public int delete(Uri uri, String where, String[] args) {
String table = getTableName(uri);
SQLiteDatabase dataBase=dbHelper.getWritableDatabase();
return dataBase.delete(table, where, args);
}
@Override
public String getType(Uri arg0) {
// TODO Auto-generated method stub
return null;
}
@Override
public Uri insert(Uri uri, ContentValues initialValues) {
String table = getTableName(uri);
SQLiteDatabase database = dbHelper.getWritableDatabase();
long value = database.insert(table, null, initialValues);
return Uri.withAppendedPath(CONTENT_URI, String.valueOf(value));
}
@Override
public Cursor query(Uri uri, String[] projection, String selection,
String[] selectionArgs, String sortOrder) {
String table =getTableName(uri);
SQLiteDatabase database = dbHelper.getReadableDatabase();
Cursor cursor =database.query(table, projection, selection, selectionArgs, null, null, sortOrder);
return cursor;
}
@Override
public int update(Uri uri, ContentValues values, String whereClause,
String[] whereArgs) {
String table = getTableName(uri);
SQLiteDatabase database = dbHelper.getWritableDatabase();
return database.update(table, values, whereClause, whereArgs);
}
public static String getTableName(Uri uri){
String value = uri.getPath();
value = value.replace("/", "");//we need to remove '/'
return value;
}
}
Here OurDatabaseHelper is the database helper class (extends SQLiteOpenHelper )
getTableName is used to get the specific Table name
Don't forget to add this in your manifest.xml file
<provider android:authorities="ourContentProviderAuthorities"
android:name=".ContentProviderDb">We specify our AUTHORITY as android:authorities
So the db operation will be like this:
Uri contentUri = Uri.withAppendedPath(ContentProviderDb.CONTENT_URI, "TableName");
Using these contentUri we are specifying our table where we need to perform our operation
We can perform db operation using our context
context.getContentResolver().insert(.....);
context.getContentResolver().query(.....);
context.getContentResolver().delete(.....);
context.getContentResolver().update(.....);
And if you are inside an activity class
getContentResolver().insert(.....);
getContentResolver().query(.....);
getContentResolver().delete(.....);
getContentResolver().update(.....);
For an example an insert operation will look like this
ContentValues initialValues = new ContentValues();
initialValues.put("Column", "value");
Uri contentUri = Uri.withAppendedPath(ContentProviderDb.CONTENT_URI, "TableName");
Uri resultUri = context.getContentResolver().insert(contentUri, initialValues);
Hope this help.
And please feel free to point out my mistakes...
