Android Contentprovider+contentobserver

Description: The article is only for my study record.

1. Understand the meaning:

ContentProvider: The content provider that operates the data as a table. the main implementation of data sharing between applications, operating system Local data (including SMS, audio, video, database).

Contentobserver: Content Watcher, monitor data changes.

2. How to use:

ContentProvider:

1) Step: New MyProvider class inherits ContentProvider class; register URI; override method (OnCreate, query, Bulkinsert, INSERT, delete, update); in Androidmanife St.xml configuration of provider;

2) Code:

Public class myprovider extends contentprovider {private static urimatcher  matcher = new urimatcher (urimatcher.no_match);p Rivate static final int  INSERT = 1;private static final int UPDATE = 2;private  static final int delete = 3;private static final int query =  4;private static final int INSERTS = 5;private DBHelper  dbopenhelper;private string tag =  "Provider";static {//  For urimatcher registration si four Urimatcher.adduri (picture.authority,  "Insert",  insert); Matcher.adduri ( picture.authority,  "Update",  update), Matcher.adduri (picture.authority,  "Delete",  delete); Matcher.adduri (picture.authority,  "Query",  query); Matcher.adduri (picture.authority,  "inserts",  inserts);//Description picture.authority: Represents the contentprovider you want to operate, generally to operateis named for the package name of the entity class. } @Overridepublic  boolean oncreate ()  {        // Gets the database helper class Dbopenhelper = dbhelper.getinstance (GetContext ());D atabasemanager.initializeinstance ( Dbopenhelper); return true;} @Overridepublic  cursor query (uri uri, string[] projection, string selection , String[] selectionargs, string sortorder)  {// todo auto-generated method  stubint code = matcher.match (URI); cursor c = null;switch  (Code)  {case query:sqlitedatabase database =  dbopenhelper.getreadabledatabase (); C = database.query ("Picture", projection,  Selection, selectionargs,null, null, sortorder); C.setnotificationuri (GetContext (). Getcontentresolver (),  uri);D atabasemanager.getinstance (). CloseDatabase (); Case urimatcher.no_match: LOG.I (tag,  "------------unknown uri"  + uri); RetuRn c;} @Overridepublic  string gettype (Uri uri)  {// todo auto-generated method  stubreturn null;} @Overridepublic  uri insert (uri uri, contentvalues values)  {int code =  matcher.match (URI);switch  (code)  {case INSERT:SQLiteDatabase database =  Databasemanager.getinstance (). OpenDatabase ();//  thread-safe concurrency Operations Database try {//  Get DB instance Database.insert (" Picture ",  null, values); GetContext (). Getcontentresolver (). Notifychange (uri, null);}  catch  (Exception ex)  {log.i (tag,  "insert ex====="  + ex.tostring ());}  finally {databasemanager.getinstance (). CloseDatabase ();} BREAK;CASE&NBSP;URIMATCHER.NO_MATCH:LOG.I (tag,  "------------unknown uri"  + uri); Return null;} /** *  BULK Insert  */@Overridepublic  int bulkinsert (uri uri, contentvalues[]  Values)  {int code =&Nbsp;matcher.match (URI);switch  (code)  {case INSERTS:SQLiteDatabase database =  Databasemanager.getinstance (). OpenDatabase ();//  thread-safe concurrency Operations Database try {//  Get DB instance Int numvalues  = 0;numValues = values.length;for  (int i = 0; i <  numvalues; i++)  {contentvalues value = values[i];d atabase.delete ("Picture",  " name = ? ", New string[] { string.valueof (Value.get (" name "))  }); LOG.I (TAG, "Name===== values" + string.valueof (Value.get ("name")));d Atabase.insert ("Picture",  Null, values[i]); LOG.I (tag,  "value insert===="  + i); GetContext (). Getcontentresolver (). Notifychange (uri, null);}  catch  (Exception ex)  {log.i (tag,  "insert ex====="  + ex.tostring ());}  finally {databasemanager.getinstance (). CloseDatabase ();} BREAK;CASE&NBSP;URIMATCHER.NO_MATCH:LOG.I (tag, "------------unknown uri"  + uri); return 0;} @Overridepublic  int delete (uri uri, string selection, string[]  Selectionargs)  {int code = matcher.match (URI);switch  (code)  {case delete: Sqlitedatabase database = databasemanager.getinstance (). OpenDatabase (); int i = 0 ; Try {i = database.delete ("Picture",  selection, selectionargs);if  (i >  0)  {getcontext (). Getcontentresolver (). Notifychange (Uri, null);}}  catch  (Exception ex)  {log.i (tag,  "delete ex===="  + ex.tostring ());}  finally {// database.close ();D atabasemanager.getinstance (). CloseDatabase ();} RETURN&NBSP;I;CASE&NBSP;URIMATCHER.NO_MATCH:LOG.I (tag,  "------------unknown uri"  + uri); return 0;} @Overridepublic  int update (Uri uri, contentvalues values, string selection, String[] selectionargs)  {// TODO Auto-generated method stubint code =  Matcher.match (URI);switch  (code)  {case UPDATE:// SQLiteDatabase database =  Dbopenhelper.getreadabledatabase (); Sqlitedatabase database = databasemanager.getinstance (). OpenDatabase (); int i = 0 ; Try {i = database.update ("Picture",  values, selection, selectionargs);if  ( i != 0)  {getcontext (). Getcontentresolver (). Notifychange (Uri, null);}}  catch  (Exception ex)  {log.i (tag,  "update ex==="  + ex.tostring ());}  finally {// database.close ();D atabasemanager.getinstance (). CloseDatabase ();} RETURN&NBSP;I;CASE&NBSP;URIMATCHER.NO_MATCH:LOG.I (tag,  "------------unknown uri"  + uri); return 0;}} Add the following methods in the database operations class. Single Data add public static void addpicture (picture picture)  {uri uri = uri.parse ("content://"  + Picture.AUTHORITY +  "/insert"); Contentvalues values = new contentvalues ();//Package Data Values.put ("name",  picture.name); Appapplication.getinstance (). Getcontentresolver (). Insert (uri, values);} Multiple Data add public static void addpictures (list<picture> pictures)  {Uri uri  = uri.parse ("content://"  + Picture.AUTHORITY +  "/inserts"); Contentvalues[] values = new contentvalues[pictures.size ()];for  (int i =  0; i < pictures.size ();  i++)  {picture picture = pictures.get ( i); Contentvalues value = new contentvalues (); Value.put ("name",  picture.name); values[i ] = value;} LOG.I (tag,  "addpictures_values_size====="  + values.length); Appapplication.getinstance (). Getcontentresolver (). Bulkinsert (uri, values);} Delete Operation public static Void deletepicturetag ()  {uri uri = uri.parse ("content://"  +  picture.authority +  "/delete"); Int i = appapplication.getinstance (). Getcontentresolver (). Delete (uri,  "wherename = ?", new string[] {  "Value"  });} Modify Operation Public static void updatepicture (Picture picture)  {Uri uri =  Uri.parse ("content://"  + Picture.AUTHORITY +  "/update"); Contentvalues values = new contentvalues (); Values.put ("Tagstatus",  picture.tagStatus) ; Int i = appapplication.getinstance (). Getcontentresolver (). Update (uri, values,  " wherename = ? ",  new string[] { picture.name }); Configuring provider<provider            in Androidmanifest.xml  android:name= "Com....provider. MyProvider "//Package name              android:authorities= "Com....provider.myprovide"  /> 

Contentobserver:

1) Step: Register and unregister contentobserver; add Contentobserver method.

2) Code:

The URI corresponds to the URI registered in provider Uri uri = uri.parse ("content://"  + picture.authority +   "/insert");//Monitor add Getcontentresolver (). Registercontentobserver (Uri, true, cob); Uri uri_inserts = uri.parse ("content://"  + Picture.AUTHORITY+  "/inserts");// Monitor bulk Add Getcontentresolver (). Registercontentobserver (Uri_inserts, true, cob); Uri uri_update = uri.parse ("content://"  + Picture.AUTHORITY +  "/update");// Monitoring modifies Getcontentresolver (). Registercontentobserver (Uri_update, true, cob); Getcontentresolver (). Unregistercontentobserver (COB);//method of destroying//monitoring data changes in OnDestroy private contentobserver cob = new  contentobserver (New handler ())  {@Overridepublic  boolean deliverselfnotifications ()  {return super.deliverselfnotifications ();} @Overridepublic  void onchange (Boolean selfchange)  {super.onchange (selfchange);// Make the appropriate action when changing the data ...}

Android Contentprovider+contentobserver