This codelab will teach you how to build a complication data provider.

Concepts and setup

At the end of the codelab, you will understand how to provide your data to watch face complications on Wear OS.

Concepts

A complication is a feature of a watch face beyond hours and minutes. The unread message count and steps indicator are examples of complications in the image below.

The Complications API is for both watch faces and data provider apps:

In this code lab, we cover creating a complication data provider. If you are also interested in adding complications to a watch face, check out our other code lab, "Adding Complications to your Watch Face".

Let's get started!

Clone the starter project repo

To help you get started quickly, we have prepared a project for you to build on. It contains some basic code and application settings necessary for the code lab.

If you have Git installed, run the command below. (You can check if Git is installed by typing git --version in the terminal / command line and verify that it executes correctly.):

 git clone https://github.com/googlecodelabs/data-providers.git

If you do not have Git, you can download the project as a zip file:

Download Zip

Import the project

Start Android Studio and select "Open an existing Android Studio project" from the Welcome screen. Open the project directory and double-click the build.gradle file in the ComplicationsDataProvider directory:

After the project has loaded, you may see an alert saying, "Unregistered VCS root detected". Click "Ignore" or the "X" in the upper-right corner. (You won't be pushing any changes back to the Git repo.)

In the upper-left corner of the project window, if you are in the Android view, you should see a set of folder icons similar to those in the screenshot below. (If you are in the Project view, expand the ComplicationsDataProvider project to see the set of folder icons.)

There are six folder icons. Each folder icon represents a module. Please note that Android Studio might take several seconds to compile the project in the background for the first time. During this time you will see a spinner in the status bar at the bottom of Android Studio:

Wait until the processes have finishes before making code changes, to allow Android Studio to pull in all the necessary components. In addition, if you get a prompt saying, "Reload for language changes to take effect?" or something similar, select "Yes".

Understand the starter project

You're set up and ready to start exposing your data to complications. We'll begin with the 1-base module. You will add code from each step to 1-base.

You can use each module in the codelab as a reference point to check your work (or as a reference if you encounter an issue). The number in the module name corresponds with the corresponding codelab step.

Overview of key components for data providers

Emulator setup

If you need help setting up a Wear OS emulator, please refer to the "Launch the emulator and run your Wear app" section of the "Creating and Running a Wearable App" page.

Run the starter project

Let's run the app on a watch.

04/20 10:00:13: Launching 1-base
$ adb push /usr/blah/blah/external/data-providers/1-base/build/outputs/apk/debug/1-base-debug.apk /data/local/tmp/com.example.android.wearable.complicationsdataprovider
$ adb shell pm install -t -r "/data/local/tmp/com.example.android.wearable.complicationsdataprovider"
Success

Please note, since this is the first time you are running this watch face, you will need to select it from "Add more watch faces". After it has been selected once, it will show up as one of the options alongside this option.

"But wait! Nothing is being displayed in the data slot I selected!" Don't worry, we aren't supplying any data yet. We will add this in the next step.

On some watches, the Elements Watch Face has complications enabled, so you might see a populated complication on your watch. Also, don't worry if your emulator has a cloud with a strikethrough in place of the airplane icon. We will not need a connection to a phone or the internet for this code lab.

Summary

In this step you've learned about:

Next up

Let's start exposing some data.

Code step 2

In this step, we will start exposing data. Complications accept several types of data. In this step, we will return the Short Text data type.

If at any point you are confused by the concepts discussed here, please refer to the "2-short-data" module and see how these steps may be implemented.

Specifying the data types your provider supports

Open the AndroidManifest.xml file and look at the service CustomComplicationProviderService. Notice the intent-filter:

<action android:name=
    "android.support.wearable.complications.ACTION_COMPLICATION_UPDATE_REQUEST"/>

This tells the system that your service extends ComplicationProviderService and can send data for complications.

Next is the meta-data element specifying the data type(s) we support. In this case, we support SMALL_IMAGE, but for this step, change that to SHORT_TEXT. Change your first meta-data element to the following:

<meta-data
    android:name="android.support.wearable.complications.SUPPORTED_TYPES"
    android:value="SHORT_TEXT"/>

Exposing your data

As stated earlier, onComplicationActivated() is called when your data provider is activated. This is a good place/time to perform any basic setup that needs to be done once per activation.

However, onComplicationUpdate()is where the active complication requests updated data.

The method onComplicationUpdate() is triggered for various reasons:

Open CustomComplicationProviderService.java and move the cursor down to the onComplicationUpdate() method. Copy and paste the code below under the initial Log.d() call:

// Used to create a unique key to use with SharedPreferences for this complication.
ComponentName thisProvider = new ComponentName(this, getClass());

// Retrieves your data, in this case, we grab an incrementing number from SharedPrefs.
SharedPreferences preferences =
       getSharedPreferences(
               ComplicationTapBroadcastReceiver.COMPLICATION_PROVIDER_PREFERENCES_FILE_KEY,
               0);
int number =
       preferences.getInt(
               ComplicationTapBroadcastReceiver.getPreferenceKey(
                       thisProvider, complicationId),
               0);
String numberText = String.format(Locale.getDefault(), "%d!", number);

In this case, we are getting a stored int in a SharedPreference that represents our data. This could easily be a call to your database.

We also convert it to a simple string in preparation for converting it to a ComplicationData object.

Next we need to convert the data into a type the complication understands. In this case, we are converting it into the SHORT_TEXT data type.

A given data type may include different sets of fields. For example, SHORT_TEXT may be just a single piece of text, or a title and text, or an icon and text.

For our case, we are only setting the required field and no optional fields. To learn more about these types and fields, review our documentation.

Copy and paste the code below under the new code you added earlier to retrieve our integer in the same method.

ComplicationData complicationData = null;

switch (dataType) {
   case ComplicationData.TYPE_SHORT_TEXT:
       complicationData =
               new ComplicationData.Builder(ComplicationData.TYPE_SHORT_TEXT)
                       .setShortText(ComplicationText.plainText(numberText))
                       .build();
       break;
   default:
       if (Log.isLoggable(TAG, Log.WARN)) {
           Log.w(TAG, "Unexpected complication type " + dataType);
       }
}

You may ask why we are using a switch to create the data. Later, we will support various forms of the data based on the type the system is requesting. By using a switch now, we can easily add new data types (LONG_TEXT, RANGED_VALUE, etc.) later.

Finally, now that we have the data in the right format, we must send the new data to the system. Copy and paste the following code after the code above.

if (complicationData != null) {
   complicationManager.updateComplicationData(complicationId, complicationData);

} else {
   // If no data is sent, we still need to inform the ComplicationManager, so the update
   // job can finish and the wake lock isn't held any longer than necessary.
   complicationManager.noUpdateRequired(complicationId);
}

Your final method should look like this:

@Override
public void onComplicationUpdate(
       int complicationId, int dataType, ComplicationManager complicationManager) {

   Log.d(TAG, "onComplicationUpdate() id: " + complicationId);

   ComponentName thisProvider = new ComponentName(this, getClass());

   SharedPreferences preferences = getSharedPreferences( ComplicationTapBroadcastReceiver.COMPLICATION_PROVIDER_PREFERENCES_FILE_KEY, 0);

   int number =
           preferences.getInt(
                   ComplicationTapBroadcastReceiver.getPreferenceKey(
                           thisProvider, complicationId),
                   0);
   String numberText = String.format(Locale.getDefault(), "%d!", number);

   ComplicationData complicationData = null;

   switch (dataType) {
       case ComplicationData.TYPE_SHORT_TEXT:
           complicationData =
                   new ComplicationData.Builder(ComplicationData.TYPE_SHORT_TEXT)
                           .setShortText(ComplicationText.plainText(numberText))
                           .build();
           break;
       default:
           if (Log.isLoggable(TAG, Log.WARN)) {
               Log.w(TAG, "Unexpected complication type " + dataType);
           }
   }

   if (complicationData != null) {
       complicationManager.updateComplicationData(complicationId, complicationData);

   } else {
       // If no data is sent, we still need to inform the ComplicationManager, so
       // the update job can finish and the wake lock isn't held any longer.
       complicationManager.noUpdateRequired(complicationId);
   }
}

Run the app again

In the first step, you learned to install your complication data service on your device or emulator. Now it's time to do that again! Install your app and reselect the complication, i.e., swipe the watch face, select the gear, navigate to the same complication, and select the Complications Data Provider Codelab. You should see something like this:

Summary

In this step you've learned:

Next up

Let's try supporting a different data type.

Code step 3

In this step, we will trigger updates in the data when the user taps our complication.

If at any point you are confused by the concepts discussed here, please refer to the "3-trigger-updates" module and see how these steps may be implemented.

Specifying how often the complication should refresh your data

Open the AndroidManifest.xml file and look again at the service CustomComplicationProviderService.

Notice an UPDATE_PERIOD_SECONDS field in the meta-data element. This specifies how often you want the system to check for updates to the data when your data provider is active.

Right now, it is set to 600 seconds (10 minutes). If you are using UPDATE_PERIOD_SECONDS, we recommend setting updates in order of minutes. Note that this value is only guidance for the system. Wear OS may update less frequently.

A better approach is a "push style" where we tell the system only when the data has changed.

Change the update frequency from 600 to 0, since we will be telling the system only when data has changed. Note that the meta-data is a requirement.

<meta-data 
    android:name="android.support.wearable.complications.UPDATE_PERIOD_SECONDS"
    android:value="0"/>

Informing the system that new complication data is available

Open ComplicationTapBroadcastReceiver.java. This BroadcastReceiver class updates our complication data when it's triggered. (Remember we are just saving the data to a SharedPreference.)

The class also offers several helper methods that construct a PendingIntent (triggers it as a BroadcastReceiver) and create unique preference keys for our complication (used with SharedPreference).

Right now, it only updates the integer in SharedPreference. We need to tell our complication that the data has been updated.

Move to the bottom of the onReceive() method. Copy and paste the code below the editor.apply() call.

// Request an update for the complication that has just been tapped.
ProviderUpdateRequester requester = new ProviderUpdateRequester(context, provider);
requester.requestUpdate(complicationId);

This instructs Wear OS that our complication's data has been updated. We need three pieces of data for this to work:

We are done with this step and your final method should look like this:

@Override
public void onReceive(Context context, Intent intent) {
   Bundle extras = intent.getExtras();
   ComponentName provider = extras.getParcelable(EXTRA_PROVIDER_COMPONENT);
   int complicationId = extras.getInt(EXTRA_COMPLICATION_ID);

   // Retrieve data via SharedPreferences.
   String preferenceKey = getPreferenceKey(provider, complicationId);
   SharedPreferences sharedPreferences =
           context.getSharedPreferences(COMPLICATION_PROVIDER_PREFERENCES_FILE_KEY, 0);

   int value = sharedPreferences.getInt(preferenceKey, 0);

   // Update data for complication.
   value = (value + 1) % MAX_NUMBER;

   SharedPreferences.Editor editor = sharedPreferences.edit();
   editor.putInt(preferenceKey, value);
   editor.apply();

   // Request an update for the complication that has just been tapped.
   ProviderUpdateRequester requester = new ProviderUpdateRequester(context, provider);
   requester.requestUpdate(complicationId);
}

Adding a tap action to our complication

Our BroadcastReceiver not only updates the data but also informs the system that new data is available (see the previous step). We need to add a tap action to our complication to trigger the BroadcastReceiver.

Open CustomComplicationProviderService.java and move down to the onComplicationUpdate() method.

Find the this line of code (the first couple of lines of the onComplicationUpdate() method).

ComponentName thisProvider = new ComponentName(this, getClass());

Recall from the previous step that this was one of the pieces of data our BroadcastReceiver needed to inform the system that our complication had new data. The other piece of data is the complication ID, which is passed into this method. We need to create a PendingIntent that passes both those values along an Extra.

Luckily, ComplicationTapBroadcastReceiver provides this as a helper method.

Copy and paste the code below under the line of code you found earlier:

// We pass the complication id, so we can only update the specific complication tapped.
PendingIntent complicationPendingIntent =
       ComplicationTapBroadcastReceiver.getToggleIntent(
               this, thisProvider, complicationId);

Next we need to assign the PendingIntent to the tap event for our complication.

Find the switch statement and replace the case for ComplicationData.TYPE_SHORT_TEXT with the code below.

case ComplicationData.TYPE_SHORT_TEXT:
   complicationData =
           new ComplicationData.Builder(ComplicationData.TYPE_SHORT_TEXT)
                   .setShortText(ComplicationText.plainText(numberText))
                   .setTapAction(complicationPendingIntent)
                   .build();
   break;

This only adds one line, the .setTapAction() method which assigns our new PendingIntent to the tap action for the complication.

We are done with this step. Your final method should look like this:

@Override
public void onComplicationUpdate(
       int complicationId, int dataType, ComplicationManager complicationManager) {
   Log.d(TAG, "onComplicationUpdate() id: " + complicationId);

   // Create Tap Action so that the user can trigger an update by tapping the complication.
   ComponentName thisProvider = new ComponentName(this, getClass());

   // We pass the complication id, so we can only update the specific complication tapped.
   PendingIntent complicationPendingIntent =
           ComplicationTapBroadcastReceiver.getToggleIntent(
                   this, thisProvider, complicationId);

   // Retrieves your data, in this case, we grab an incrementing number from SharedPrefs.
   SharedPreferences preferences =
           getSharedPreferences(
                   ComplicationTapBroadcastReceiver.COMPLICATION_PROVIDER_PREFERENCES_FILE_KEY,
                   0);
   int number =
           preferences.getInt(
                   ComplicationTapBroadcastReceiver.getPreferenceKey(
                           thisProvider, complicationId),
                   0);
   String numberText = String.format(Locale.getDefault(), "%d!", number);

   ComplicationData complicationData = null;

   switch (dataType) {
       case ComplicationData.TYPE_SHORT_TEXT:
           complicationData =
                   new ComplicationData.Builder(ComplicationData.TYPE_SHORT_TEXT)
                           .setShortText(ComplicationText.plainText(numberText))
                           .setTapAction(complicationPendingIntent)
                           .build();
           break;
       default:
           if (Log.isLoggable(TAG, Log.WARN)) {
               Log.w(TAG, "Unexpected complication type " + dataType);
           }
   }

   if (complicationData != null) {
       complicationManager.updateComplicationData(complicationId, complicationData);

   } else {
        // If no data is sent, we still need to inform the ComplicationManager,
        // so the update job can finish and the wake lock isn't held any longer
        // than necessary.
       complicationManager.noUpdateRequired(complicationId);
   }
}

Run the app again

Install your app and reselect the complication, i.e., swipe the watch face, select the gear, navigate to the same complication, and select the Complications Data Provider Codelab provider. You should see the same thing as you saw before. However, now you can tap the complication and the data will be updated.

Summary

In this step you've learned:

Next up

Let's try supporting a different data type.

Code step 4

As we expose our data to complications, it might be nice to support more types of data, and to see what different data types look like in complications.

Specifying a different supported data type

Open the AndroidManifest.xml file again and look at the declaration of the service CustomComplicationProviderService.

Change the meta-data element SUPPORTED_TYPES from SHORT_TEXT to LONG_TEXT. Your change should look like this:

<meta-data
    android:name="android.support.wearable.complications.SUPPORTED_TYPES"
    android:value="LONG_TEXT"/>

Adding support for LONG TEXT

Open CustomComplicationProviderService.java, move down to the switch statement in the onComplicationUpdate() method, and add the following code below the end of the TYPE_SHORT_TEXT case and above the default case.

case ComplicationData.TYPE_LONG_TEXT:
   complicationData =
           new ComplicationData.Builder(ComplicationData.TYPE_LONG_TEXT)
                   .setLongText(ComplicationText.plainText("Number: " + numberText))
                   .setTapAction(complicationPendingIntent)
                   .build();
   break;

The switch statement should look something like this:

switch (dataType) {
   case ComplicationData.TYPE_SHORT_TEXT:
       complicationData =
               new ComplicationData.Builder(ComplicationData.TYPE_SHORT_TEXT)
                       .setShortText(ComplicationText.plainText(numberText))
                       .setTapAction(complicationPendingIntent)
                       .build();
       break;
   case ComplicationData.TYPE_LONG_TEXT:
       complicationData =
               new ComplicationData.Builder(ComplicationData.TYPE_LONG_TEXT)
                       .setLongText(ComplicationText.plainText("Number: " + numberText))
                       .setTapAction(complicationPendingIntent)
                       .build();
       break;
   default:
       if (Log.isLoggable(TAG, Log.WARN)) {
           Log.w(TAG, "Unexpected complication type " + dataType);
       }
}

You may have noticed that we are simply repackaging the same data in a new format. Let's see how it looks.

How to check your progress and debug

Install your service, but this time choose the bottom slot complication before choosing your complication service provider:

You should see something like the image below. Note that each complication is stored under a separate key, so you might see different values if you have set the complication in multiple locations:

Summary

In this step you've learned about:

Next up

We want to support one extra data type before putting it all together.

Code step 5

While we expose our data to complications, let's continue exploring how to support more types of data.

Specifying a different supported data type

Open the AndroidManifest.xml file again and take a look at the service CustomComplicationProviderService.

Change the meta-data element SUPPORTED_TYPES to RANGED_VALUE. Your change should should look like this:

<meta-data
    android:name="android.support.wearable.complications.SUPPORTED_TYPES"
    android:value="RANGED_VALUE"/>

Adding support for RANGED VALUES

Open CustomComplicationProviderService.java, move your cursor down to the switch statement in the onComplicationUpdate() method, and add this code under the TYPE_LONG_TEXT case and above the default case:

case ComplicationData.TYPE_RANGED_VALUE:
   complicationData =
           new ComplicationData.Builder(ComplicationData.TYPE_RANGED_VALUE)
                   .setValue(number)
                   .setMinValue(0)
                   .setMaxValue(ComplicationTapBroadcastReceiver.MAX_NUMBER)
                   .setShortText(ComplicationText.plainText(numberText))
                   .setTapAction(complicationPendingIntent)
                   .build();
   break;

Your switch statement should look like this:

switch (dataType) {
   case ComplicationData.TYPE_SHORT_TEXT:
       complicationData =
               new ComplicationData.Builder(ComplicationData.TYPE_SHORT_TEXT)
                       .setShortText(ComplicationText.plainText(numberText))
                       .setTapAction(complicationPendingIntent)
                       .build();
       break;
   case ComplicationData.TYPE_LONG_TEXT:
       complicationData =
               new ComplicationData.Builder(ComplicationData.TYPE_LONG_TEXT)
                       .setLongText(ComplicationText.plainText("Number: " + numberText))
                       .setTapAction(complicationPendingIntent)
                       .build();
       break;
   case ComplicationData.TYPE_RANGED_VALUE:
       complicationData =
               new ComplicationData.Builder(ComplicationData.TYPE_RANGED_VALUE)
                       .setValue(number)
                       .setMinValue(0)
                       .setMaxValue(ComplicationTapBroadcastReceiver.MAX_NUMBER)
                       .setShortText(ComplicationText.plainText(numberText))
                       .setTapAction(complicationPendingIntent)
                       .build();
       break;
   default:
       if (Log.isLoggable(TAG, Log.WARN)) {
           Log.w(TAG, "Unexpected complication type " + dataType);
       }
}

Again, we are just repackaging the same data in a new format. Let's see how it looks.

How to check your progress and debug

Install your service, and choose another location.

You should now see something like this:

You can see a radial circle around the number that highlights the equivalent of 5/20.

Summary

In this step you've learned about:

Next up

We wrap up the code lab by enabling all the data type variations.

Code step 6

Now our complication data provider supports three variations of our data (RANGED_VALUE, SHORT_TEXT, and LONG_TEXT).

In this last step, we will inform the system we support all three variations.

Specifying multiple supported data types

Open the AndroidManifest.xml file again and look at the service CustomComplicationProviderService.

Change the meta-data element SUPPORTED_TYPES to RANGED_VALUE,SHORT_TEXT,LONG_TEXT. Your change should now look like this:

<meta-data
    android:name="android.support.wearable.complications.SUPPORTED_TYPES"
    android:value="RANGED_VALUE,SHORT_TEXT,LONG_TEXT"/>

Check your progress

Install your service.

In this case, the watch face prefers the ranged data type over the short and long types, but if the complication only supported the short text type, the data would still show up because the watch face supports all three data types. Keep in mind the watch face itself specifies the data types that a complication supports, and the order of preference of those types.

Summary

In this step you've learned about:

There are many more data types you can support in complications (including small images, large images, and icons). Try to extend this code lab by implementing some of those types on your own.

For more details on developing complications for watch faces and creating complication data providers, visit Watch Face Complications

For more details about developing Wear OS watch faces, visit https://developer.android.com/training/wearables/watch-faces/index.html

Also watch these great videos: