android contentresolver有啥使用技巧

Android ContentResolver ??????????????????????????????,??????????? ContentResolver:

1. ?? Content Resolver ????:

   • ?? query() ??????????? URI?????(???????)???????(??????)???????????
   • ??:??????????????

     Uri contactsUri = ContactsContract.Contacts.CONTENT_URI;
     String[] projection = {ContactsContract.Contacts._ID, ContactsContract.Contacts.DISPLAY_NAME, ContactsContract.Contacts.Phone_NUMBERS};
     String selection = "((" + ContactsContract.Contacts.DISPLAY_NAME + " LIKE ?) AND (" + ContactsContract.Contacts.Phone_NUMBERS + " LIKE ?))";
     String[] selectionArgs = {"%John%", "3%"};
     Cursor cursor = getContentResolver().query(contactsUri, projection, selection, selectionArgs, null);
     

2. ????:

   • ?? insert() ??????????? URI ???????(? ContentValues ?????)?
   • ??:????????????

     Uri contactsUri = ContactsContract.Contacts.CONTENT_URI;
     ContentValues contentValues = new ContentValues();
     contentValues.put(ContactsContract.Contacts.DISPLAY_NAME, "John Doe");
     contentValues.put(ContactsContract.Contacts.Phone_NUMBERS, "123-456-7890");
     Uri newContactUri = getContentResolver().insert(contactsUri, contentValues);
     

3. ????:

   • ?? update() ??????????? URI???????(? ContentValues ?????)????????
   • ??:???????????

     Uri contactsUri = ContactsContract.Contacts.CONTENT_URI;
     String selection = ContactsContract.Contacts._ID + "=?";
     String[] selectionArgs = {"1"};
     ContentValues contentValues = new ContentValues();
     contentValues.put(ContactsContract.Contacts.Phone_NUMBERS, "098-765-4321");
     getContentResolver().update(contactsUri, contentValues, selection, selectionArgs);
     

4. ????:

   • ?? delete() ??????????? URI ????????
   • ??:???? "John Doe" ?????

     Uri contactsUri = ContactsContract.Contacts.CONTENT_URI;
     String selection = ContactsContract.Contacts.DISPLAY_NAME + "=?";
     String[] selectionArgs = {"John Doe"};
     getContentResolver().delete(contactsUri, selection, selectionArgs);
     

5. ?? Content Resolver ??????:

   • ???????,????? ContentObserver ????? onChange() ?????,?? getContentResolver().registerContentObserver() ???? ContentObserver?
   • ??:??????????????

     Uri contactsUri = ContactsContract.Contacts.CONTENT_URI;
     getContentResolver().registerContentObserver(contactsUri, true, new ContentObserver(new Handler()) {
         @Override
         public void onChange(boolean selfChange) {
             super.onChange(selfChange);
             // ????????????
         }
     });
     

6. ?? Content Resolver ???????????:

   • ????????????,???????? Content URI???,?? URI ???????????????????
   • ??:???????????????

     Uri imagesUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
     String[] projection = {MediaStore.Images.Media._ID, MediaStore.Images.Media.DISPLAY_NAME};
     Cursor cursor = getContentResolver().query(imagesUri, projection, null, null, null);
     

??????????,????????? Android ContentResolver ???????????????????