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Content provider

By using content provider, users can choose to share only some part of the data in one application, thus can avoid privacy data leak in the program. At present, the use of content provider is the standard way for Android to share data across applications.

Content resolver: Each android application can be a content provider. For example, android phone contacts, short message system and android media library.; To get data from a content provider, you need to use a ContentResolver instance in your app. Generally the ContentResolver instance can be obtained by Activity‘s getContentResolver method.
Content URI: Content URI is a unique resource identifier that content provider app provides for client app to access it’s shared data.

Query Content Provider Data

query(Uri uri, String columnArray[], String whereClause, String wherePlaceHolderValue[], String orderByClause)
The query method return a android.database.Cursor object, if it is not null, then use it’s moveToFirst method to move to the first row.Then loop in the cursor to get each row use it’s moveToNext method.

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Broadcast receiver

A broadcast receiver (receiver) is an Android component which allows you to register for system or application events. All registered receivers for an event are notified by the Android runtime once this event happens.

For example, applications can register for the ACTION_BOOT_COMPLETED system event which is fired once the Android system has completed the boot process.

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