Question

Learning Android I’m trying to find contacts using DISPLAY_NAME selector. I need to find all contacts with given name. Everything goes great using standard query, but falls when I use ContentProviderOperation. I do not understand some of features. When debugging i see exception: Empty values. But, which values I must insert there? Thanks.

    op.add(ContentProviderOperation.newAssertQuery(ContactsContract.Contacts.CONTENT_URI)
      .withSelection(ContactsContract.Contacts.DISPLAY_NAME + " = '" + name + "'", new String[] {ContactsContract.Contacts._ID})
      .build());        
    try {
        result = getContentResolver().applyBatch(ContactsContract.AUTHORITY, op);
    } catch (Exception e) {

    }       

Answer 1

the problem is with your second line of code which should read:

.withSelection(
    ContactsContract.Contacts.DISPLAY_NAME + " = ?",
    new String[] {name}
)

To explain, the withSelection method takes two parameters, the selection string and an array selectionArgs, these are substituted into the selection string during query compilation. So in this example the ? is subtituted for the value of name. Text qualifiers (single quotes) are automatically embedded at the same time so no additional effort is required