When using the Android search dialog, you can provide custom search suggestions that are created from data in your application. For example, if your application is a word dictionary, you can suggest words from the dictionary that match the text entered so far. These are the most valuable suggestions, because you can effectively predict what the user wants and provide instant access to it. Figure 1 shows an example of a search dialog with custom suggestions.
Once you provide custom suggestions, you can also make them available to the system-wide Quick Search Box, providing access to your content from outside your application.
Before you begin with this guide to add custom suggestions, you need to have implemented the Android search dialog for searches in your application. If you haven't, see Using the Android Search Dialog.
When the user selects a custom suggestion, the Search Manager sends an Intent
to
your searchable Activity. Whereas a normal search query sends an Intent with the ACTION_SEARCH
action, you can instead define your custom suggestions to use
ACTION_VIEW
(or any other Intent action), and also include data
that's relevant to the selected suggestion. Continuing
the dictionary example, when the user selects a suggestion, your application can immediately
open the definition for that word, instead of searching the dictionary for matches.
To provide custom suggestions, do the following:
SQLiteDatabase
) for your
suggestions and format the table with required columns.Intent
to be sent when the user selects a
suggestion (including a custom action and custom data). Just like the Search Manager displays the search dialog, it also displays your search suggestions. All you need is a content provider from which the Search Manager can retrieve your suggestions. If you're not familiar with creating content providers, read the Content Providers developer guide before you continue.
When the Search Manager identifies that your Activity is searchable and provides search suggestions, the following procedure takes place as soon as the user enters text into the search dialog:
Cursor
that points to all
suggestions that are relevant to the search query text.Once the custom suggestions are displayed, the following might happen:
ACTION_SEARCH
Intent.To add support for custom suggestions, add the android:searchSuggestAuthority
attribute
to the <searchable>
element in your searchable configuration file. For example:
<?xml version="1.0" encoding="utf-8"?> <searchable xmlns:android="http://schemas.android.com/apk/res/android" android:label="@string/app_label" android:hint="@string/search_hint" android:searchSuggestAuthority="com.example.MyCustomSuggestionProvider"> </searchable>
You might need some additional attributes, depending on the type of Intent you attach to each suggestion and how you want to format queries to your content provider. The other optional attributes are discussed in the following sections.
Creating a content provider for custom suggestions requires previous knowledge about content
providers that's covered in the Content Provider developer
guide. For the most part, a content provider for custom suggestions is the
same as any other content provider. However, for each suggestion you provide, the respective row in
the Cursor
must include specific columns that the Search Manager
understands and uses to format the suggestions.
When the user starts typing into the search dialog, the Search Manager queries your content
provider for suggestions by calling query()
each time
a letter is typed. In your implementation of query()
, your
content provider must search your suggestion data and return a Cursor
that points to the rows you have determined to be good suggestions.
Details about creating a content provider for custom suggestions are discussed in the following two sections:
Cursor
returned with each queryWhen the Search Manager requests suggestions from your content provider, it calls your content
provider's query()
method. You must
implement this method to search your suggestion data and return a
Cursor
pointing to the suggestions you deem relevant.
Here's a summary of the parameters that the Search Manager passes to your query()
method
(listed in order):
uri
Uri
, formatted as:
content://your.authority/optional.suggest.path/SUGGEST_URI_PATH_QUERY
The default behavior is for Search Manager to pass this URI and append it with the query text. For example:
content://your.authority/optional.suggest.path/SUGGEST_URI_PATH_QUERY
/puppies
The query text on the end is encoded using URI encoding rules, so you might need to decode it before performing a search.
The optional.suggest.path
portion is only included in the URI if you have set
such a path in your searchable configuration file with the android:searchSuggestPath
attribute. This is only needed if you use the same content provider for multiple searchable
activities, in which case, you need to disambiguate the source of the suggestion query.
Note: SUGGEST_URI_PATH_QUERY
is not the literal
string provided in the URI, but a constant that you should use if you need to refer to this
path.
projection
selection
android:searchSuggestSelection
attribute of
your searchable configuration file, or null if you have not declared the android:searchSuggestSelection
attribute. More about using this to get the
query below.selectionArgs
android:searchSuggestSelection
attribute in your searchable configuration. If
you have not declared android:searchSuggestSelection
, then this parameter is null. More
about using this to get the query below.sortOrder
The Search Manager can send you the search query text in two ways. The
default manner is for the query text to be included as the last path of the content
URI passed in the uri
parameter. However, if you include a selection value in your
searchable configuration's android:searchSuggestSelection
attribute, then the query text is instead passed as the first
element of the selectionArgs
string array. Both options are summarized next.
By default, the query is appended as the last segment of the uri
parameter (a Uri
object). To retrieve the query text in this case, simply use
getLastPathSegment()
. For example:
String query = uri.getLastPathSegment().toLowerCase();
This returns the last segment of the Uri
, which is the query text entered in
the search dialog.
Instead of using the URI, you might decide it makes more sense for your query()
method to
receive everything it needs to perform the look-up and you want the
selection
and selectionArgs
parameters to carry the appropriate values. In such a
case, add the android:searchSuggestSelection
attribute to your searchable configuration with
your SQLite selection string. In the selection string, include a question mark ("?") as
a placeholder for the actual search query. The Search Manager calls query()
with the
selection string as the selection
parameter and the search query as the first
element in the selectionArgs
array.
For example, here's how you might form the android:searchSuggestSelection
attribute to
create a full-text search statement:
<?xml version="1.0" encoding="utf-8"?> <searchable xmlns:android="http://schemas.android.com/apk/res/android" android:label="@string/app_label" android:hint="@string/search_hint" android:searchSuggestAuthority="com.example.MyCustomSuggestionProvider" android:searchSuggestIntentAction="android.Intent.action.VIEW" android:searchSuggestSelection="word MATCH ?"> </searchable>
With this configuration, your query()
method
delivers the selection
parameter as "word MATCH ?" and the selectionArgs
parameter as whatever the user entered in the search dialog. When you pass these to an SQLite
query()
method, as their respective arguments, they are synthesized together (the
question mark is replaced with the query
text). If you chose to receive suggestion queries this way and need to add wildcards to
the query text, append (and/or prefix) them to the selectionArgs
parameter, because this value is wrapped in quotes and inserted in place of the
question mark.
Another new attribute in the example above is android:searchSuggestIntentAction
, which
defines the Intent action sent with each Intent when the user selects a suggestion. It is
discussed further in the section about Declaring an Intent for
suggestions.
Tip: If you don't want to define a selection clause in
the android:searchSuggestSelection
attribute, but would still like to receive the query
text in the selectionArgs
parameter, simply provide a non-null value for the android:searchSuggestSelection
attribute. This triggers the query to be passed in selectionArgs
and you can ignore the selection
parameter. In this way, you can instead
define the actual selection clause at a lower level so that your content provider doesn't have to
handle it.
If your search suggestions are not stored in a table format (such as an SQLite table) using the
columns required by the
Search Manager, then you can search your suggestion data for matches and then format them
into the necessary table on each request. To do so, create a MatrixCursor
using the required column names and then add a row for each suggestion using addRow(Object[])
. Return the final product from your Content
Provider's query()
method.
When you return suggestions to the Search Manager with a Cursor
, the
Search Manager expects specific columns in each row. So, regardless of whether you
decide to store
your suggestion data in an SQLite database on the device, a database on a web server, or another
format on the device or web, you must format the suggestions as rows in a table and
present them with a Cursor
. The Search
Manager understands several columns, but only two are required:
_ID
SUGGEST_COLUMN_TEXT_1
The following columns are all optional (and most are discussed further in the following sections):
SUGGEST_COLUMN_TEXT_2
SUGGEST_COLUMN_ICON_1
SUGGEST_COLUMN_ICON_2
SUGGEST_COLUMN_INTENT_ACTION
android:searchSuggestIntentAction
field in your
searchable configuration. If your action is the same for all
suggestions, it is more efficient to specify the action using android:searchSuggestIntentAction
and omit this column.SUGGEST_COLUMN_INTENT_DATA
android:searchSuggestIntentData
field in your searchable configuration. If
neither source is provided,
the Intent's data field is null. If your data is the same for all suggestions, or can be
described using a constant part and a specific ID, it is more efficient to specify it using android:searchSuggestIntentData
and omit this column.
SUGGEST_COLUMN_INTENT_DATA_ID
android:searchSuggestIntentData
attribute in the searchable configuration has already
been set to an appropriate base string.SUGGEST_COLUMN_INTENT_EXTRA_DATA
EXTRA_DATA_KEY
key.SUGGEST_COLUMN_QUERY
QUERY
key. Required if suggestion's action is ACTION_SEARCH
, optional otherwise.SUGGEST_COLUMN_SHORTCUT_ID
SUGGEST_NEVER_MAKE_SHORTCUT
, the result is
not stored as a shortcut.
Otherwise, the shortcut ID is used to check back for an up to date suggestion using
SUGGEST_URI_PATH_SHORTCUT
.SUGGEST_COLUMN_SPINNER_WHILE_REFRESHING
SUGGEST_COLUMN_ICON_2
while the shortcut of this suggestion is being refreshed in Quick Search Box.Some of these columns are discussed more in the following sections.
When the user selects a suggestion from the list that appears below the search dialog, the Search
Manager sends a custom Intent
to your searchable Activity. You must define
the action and data for the Intent.
The most common Intent action for a custom suggestion is ACTION_VIEW
, which is appropriate when
you want to open something, like the definition for a word, a person's contact information, or a web
page. However, the Intent action can be any other action and can even be different for each
suggestion.
Depending on whether you want all suggestions to use the same Intent action, you can define the action in two ways:
android:searchSuggestIntentAction
attribute of your searchable configuration
file to define the action for all suggestions. For example:
<?xml version="1.0" encoding="utf-8"?> <searchable xmlns:android="http://schemas.android.com/apk/res/android" android:label="@string/app_label" android:hint="@string/search_hint" android:searchSuggestAuthority="com.example.MyCustomSuggestionProvider" android:searchSuggestIntentAction="android.Intent.action.VIEW" > </searchable>
SUGGEST_COLUMN_INTENT_ACTION
column to define the
action for individual suggestions.
Add the SUGGEST_COLUMN_INTENT_ACTION
column to
your suggestions table and, for each suggestion, place in it the action to use (such as
"android.Intent.action.VIEW"
).
You can also combine these two techniques. For instance, you can include the android:searchSuggestIntentAction
attribute with an action to be used with all suggestions by
default, then override this action for some suggestions by declaring a different action in the
SUGGEST_COLUMN_INTENT_ACTION
column. If you do not include
a value in the SUGGEST_COLUMN_INTENT_ACTION
column, then the
Intent provided in the android:searchSuggestIntentAction
attribute is used.
Note: If you do not include the
android:searchSuggestIntentAction
attribute in your searchable configuration, then you
must include a value in the SUGGEST_COLUMN_INTENT_ACTION
column for every suggestion, or the Intent will fail.
When the user selects a suggestion, your searchable Activity receives the Intent with the
action you've defined (as discussed in the previous section), but the Intent must also carry
data in order for your Activity to identify which suggestion was selected. Specifically,
the data should be something unique for each suggestion, such as the row ID for the suggestion in
your SQLite table. When the Intent is received,
you can retrieve the attached data with getData()
or getDataString()
.
You can define the data included with the Intent in two ways:
SUGGEST_COLUMN_INTENT_DATA
column of your suggestions table.
Provide all necessary data information for each Intent in the suggestions table by including the
SUGGEST_COLUMN_INTENT_DATA
column and then populating it with
unique data for each row. The data from this column is attached to the Intent exactly as you
define it in this column. You can then retrieve it with with getData()
or getDataString()
.
Tip: It's usually easiest to use the table's row ID as the
Intent data, because it's always unique. And the easiest way to do that is by using the
SUGGEST_COLUMN_INTENT_DATA
column name as an alias for the row ID
column. See the Searchable Dictionary sample
app for an example in which SQLiteQueryBuilder
creates a
projection map of column names to aliases.
android:searchSuggestIntentData
attribute of the searchable configuration and the SUGGEST_COLUMN_INTENT_DATA_ID
column of your
suggestions table, respectively.
Declare the piece of the URI that is common to all suggestions in the android:searchSuggestIntentData
attribute of your searchable configuration. For example:
<?xml version="1.0" encoding="utf-8"?> <searchable xmlns:android="http://schemas.android.com/apk/res/android" android:label="@string/app_label" android:hint="@string/search_hint" android:searchSuggestAuthority="com.example.MyCustomSuggestionProvider" android:searchSuggestIntentAction="android.Intent.action.VIEW" android:searchSuggestIntentData="content://com.example/datatable" > </searchable>
Then include the final path for each suggestion (the unique part) in the SUGGEST_COLUMN_INTENT_DATA_ID
column of your suggestions table. When the user selects a suggestion, the Search Manager takes
the string from android:searchSuggestIntentData
, appends a slash ("/") and then adds the
respective value from the SUGGEST_COLUMN_INTENT_DATA_ID
column to
form a complete content URI. You can then retrieve the Uri
with with getData()
.
If you need to express even more information with your Intent, you can add another table column,
SUGGEST_COLUMN_INTENT_EXTRA_DATA
, which can store additional
information about the suggestion. The data saved in this column is placed in EXTRA_DATA_KEY
of the Intent's extra Bundle.
Now that your search dialog provides custom search suggestions with custom Intents, you
need your searchable Activity to handle these Intents when the user selects a
suggestion. This is in addition to handling the ACTION_SEARCH
Intent, which your searchable Activity already does.
Here's an example of how you can handle the Intents during your Activity onCreate()
callback:
Intent intent = getIntent(); if (Intent.ACTION_SEARCH.equals(intent.getAction())) { // Handle the normal search query case String query = intent.getStringExtra(SearchManager.QUERY); doSearch(query); } else if (Intent.ACTION_VIEW.equals(intent.getAction())) { // Handle a suggestions click (because the suggestions all use ACTION_VIEW) Uri data = intent.getData(); showResult(data); }
In this example, the Intent action is ACTION_VIEW
and the data carries a complete URI pointing to the suggested
item, as synthesized by the android:searchSuggestIntentData
string and SUGGEST_COLUMN_INTENT_DATA_ID
column. The URI is then passed to the local
showResult()
method that queries the content provider for the item specified by the URI.
Note: You do not need to add an Intent filter to your
Android manifest file for the Intent action you defined with the android:searchSuggestIntentAction
attribute or SUGGEST_COLUMN_INTENT_ACTION
column. The Search Manager opens your
searchable Activity by name to deliver the suggestion's Intent, so the Activity does not need to
declare the accepted action.
If the user navigates through the suggestions list using the directional controls (trackball or d-pad), the text in the search dialog won't change, by default. However, you can temporarily rewrite the user's query text as it appears in the text box with a query that matches the suggestion currently in focus. This enables the user to see what query is being suggested (if appropriate) and then select the search box and edit the query before dispatching it as a search.
You can rewrite the query text in the following ways:
android:searchMode
attribute to your searchable configuration with the
"queryRewriteFromText" value. In this case, the content from the suggestion's SUGGEST_COLUMN_TEXT_1
column is used to rewrite the query text.android:searchMode
attribute to your searchable configuration with the
"queryRewriteFromData" value. In this case, the content from the suggestion's
SUGGEST_COLUMN_INTENT_DATA
column is used to rewrite the
query text. This should only
be used with URI's or other data formats that are intended to be user-visible, such as HTTP URLs.
Internal URI schemes should not be used to rewrite the query in this way.SUGGEST_COLUMN_QUERY
column of your suggestions table. If this column is
present and contains a value for the current suggestion, it is used to rewrite the query text
(and override either of the previous implementations).Once you configure your application to provide custom search suggestions, making them available
to the globally accessible Quick Search Box is as easy as modifying your searchable configuration to
include android:includeInGlobalSearch
as "true".
The only scenario in which additional work is necessary is when your content provider demands a
read permission. In which case, you need to add a special
<path-permission>
element for the provider to grant Quick Search Box read access to
your content provider. For example:
<provider android:name="MySuggestionProvider" android:authorities="com.example.MyCustomSuggestionProvider" android:readPermission="com.example.provider.READ_MY_DATA" android:writePermission="com.example.provider.WRITE_MY_DATA"> <path-permission android:pathPrefix="/search_suggest_query" android:readPermission="android.permission.GLOBAL_SEARCH" /> </provider>
In this example, the provider restricts read and write access to the content. The
<path-permission>
element amends the restriction by granting read access to content
inside the "/search_suggest_query"
path prefix when the "android.permission.GLOBAL_SEARCH"
permission exists. This grants access to Quick Search Box
so that it may query your content provider for suggestions.
If your content provider does not enforce read permissions, then Quick Search Box can read it by default.
When your application is configured to provide suggestions in Quick Search Box, it is not actually enabled to provide suggestions in Quick Search Box, by default. It is the user's choice whether to include suggestions from your application in the Quick Search Box. To enable search suggestions from your application, the user must open "Searchable items" (in Settings > Search) and enable your application as a searchable item.
Each application that is available to Quick Search Box has an entry in the Searchable items
settings page. The entry includes the name of the application and a short description of what
content can be searched from the application and made available for suggestions in Quick Search Box.
To define the description text for your searchable application, add the android:searchSettingsDescription
attribute to your searchable configuration. For example:
<?xml version="1.0" encoding="utf-8"?> <searchable xmlns:android="http://schemas.android.com/apk/res/android" android:label="@string/app_label" android:hint="@string/search_hint" android:searchSuggestAuthority="com.example.MyCustomSuggestionProvider" android:searchSuggestIntentAction="android.Intent.action.VIEW" android:includeInGlobalSearch="true" android:searchSettingsDescription="@string/search_description" > </searchable>
The string for android:searchSettingsDescription
should be as concise as possible and
state the content that is searchable. For example, "Artists, albums, and tracks" for a music
application, or "Saved notes" for a notepad application. Providing this description is important so
the user knows what kind of suggestions are provided. You should always include this attribute
when android:includeInGlobalSearch
is "true".
Remember that the user must visit the settings menu to enable search suggestions for your application before your search suggestions appear in Quick Search Box. As such, if search is an important aspect of your application, then you might want to consider a way to convey that to your users — you might provide a note the first time they launch the app that instructs them how to enable search suggestions for Quick Search Box.
Suggestions that the user selects from Quick Search Box can be automatically made into shortcuts. These are suggestions that the Search Manager has copied from your content provider so it can quickly access the suggestion without the need to re-query your content provider.
By default, this is enabled for all suggestions retrieved by Quick Search Box, but if your
suggestion data changes over time, then you can request that the shortcuts be refreshed. For
instance, if your suggestions refer to dynamic data, such as a contact's presence status, then you
should request that the suggestion shortcuts be refreshed when shown to the user. To do so,
include the SUGGEST_COLUMN_SHORTCUT_ID
in your suggestions table.
Using this column, you can
configure the shortcut behavior for each suggestion in one of the following ways:
Provide a value in the SUGGEST_COLUMN_SHORTCUT_ID
column
and the suggestion is
re-queried for a fresh version each time the shortcut is displayed. The shortcut
is quickly displayed with whatever data was most recently available until the refresh query
returns, at which point the suggestion is refreshed with the new information. The
refresh query is sent to your content provider with a URI path of SUGGEST_URI_PATH_SHORTCUT
(instead of SUGGEST_URI_PATH_QUERY
).
The Cursor
you return should contain one suggestion using the
same columns as the original suggestion, or be empty, indicating that the shortcut is no
longer valid (in which case, the suggestion disappears and the shortcut is removed).
If a suggestion refers to data that could take longer to refresh, such as a network-based
refresh, you can also add the SUGGEST_COLUMN_SPINNER_WHILE_REFRESHING
column to your suggestions
table with a value
of "true" in order to show a progress spinner for the right hand icon until the refresh is complete.
Any value other than "true" does not show the progress spinner.
Provide a value of SUGGEST_NEVER_MAKE_SHORTCUT
in the
SUGGEST_COLUMN_SHORTCUT_ID
column. In
this case, the suggestion is never copied into a shortcut. This should only be necessary if you
absolutely do not want the previously copied suggestion to appear. (Recall that if you
provide a normal value for the column, then the suggestion shortcut appears only until the
refresh query returns.)
Leave the SUGGEST_COLUMN_SHORTCUT_ID
empty for each
suggestion that will not change and can be saved as a shortcut.
If none of your suggestions ever change, then you do not need the
SUGGEST_COLUMN_SHORTCUT_ID
column at all.
Note: Quick Search Box ultimately decides whether or not to create a shortcut for a suggestion, considering these values as a strong request from your application—there is no guarantee that the behavior you have requested for your suggestion shortcuts will be honored.
Once you make your application's search suggestions available to Quick Search Box, the Quick Search Box ranking determines how the suggestions are surfaced to the user for a particular query. This might depend on how many other apps have results for that query, and how often the user has selected your results compared to those from other apps. There is no guarantee about how your suggestions are ranked, or whether your app's suggestions show at all for a given query. In general, you can expect that providing quality results increases the likelihood that your app's suggestions are provided in a prominent position and apps that provide low quality suggestions are more likely to be ranked lower or not displayed.
See the Searchable Dictionary sample app for a complete demonstration of custom search suggestions.