The Android Gmail app includes a content provider that third party developers can use to retrieve label information like name and unread count, and stay updated as that information changes. For example, an app or widget could display the unread count of a specific account's inbox.
Before using this content provider, call the
GmailContract.canReadLabels(Context)
method to determine whether the user's version of the Gmail app supports these
queries.
Find a valid Gmail account to query
An app must first find the email address of a valid Gmail account to query for
label information. With the
GET_ACCOUNTS
permission, the
AccountManager
can return this information:
// Get the account list, and pick the first one
final String ACCOUNT_TYPE_GOOGLE = "com.google";
final String[] FEATURES_MAIL = {
"service_mail"
};
AccountManager.get(this).getAccountsByTypeAndFeatures(ACCOUNT_TYPE_GOOGLE, FEATURES_MAIL,
new AccountManagerCallback() {
@Override
public void run(AccountManagerFuture future) {
Account[] accounts = null;
try {
accounts = future.getResult();
if (accounts != null && accounts.length > 0) {
String selectedAccount = accounts[0].name;
queryLabels(selectedAccount);
}
} catch (OperationCanceledException oce) {
// TODO: handle exception
} catch (IOException ioe) {
// TODO: handle exception
} catch (AuthenticatorException ae) {
// TODO: handle exception
}
}
}, null /* handler */);
Query the content provider
With an email address selected, you can then obtain a
ContentProvider
URI to query against. We've provided a simple class called
GmailContract.java
to construct the URI and define the columns returned.
An app can query this URI directly — or better yet, use a
CursorLoader
— to obtain a Cursor with information for all labels on an account:
Cursor labelsCursor = getContentResolver().query(GmailContract.Labels.getLabelsUri(selectedAccount), null, null, null, null);
With the data in this cursor, you can then persist the URI value in the
GmailContract.Labels.URI
column to query and watch for changes on a
single label.
The NAME
value for pre-defined labels can vary by locale, so don't
use GmailContract.Labels.NAME
. Instead, you can programmatically
identify pre-defined labels like Inbox, Sent or Drafts using the String value in
the GmailContract.Labels.CANONICAL_NAME
column:
// loop through the cursor and find the Inbox
if (labelsCursor != null) {
final String inboxCanonicalName = GmailContract.Labels.LabelCanonicalName.CANONICAL_NAME_INBOX;
final int canonicalNameIndex = labelsCursor.getColumnIndexOrThrow(GmailContract.Labels.CANONICAL_NAME);
while (labelsCursor.moveToNext()) {
if (inboxCanonicalName.equals(labelsCursor.getString(canonicalNameIndex))) {
// this row corresponds to the Inbox
}
}
}
For more help, read Content provider basics
Review an example
To see an example of this content provider in action, download a sample app.