ui/fonts/DownloadableFonts/template-params.xml

<?xml version="1.0" encoding="UTF-8"?>
<!--
 Copyright 2017 The Android Open Source Project

 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at

     http://www.apache.org/licenses/LICENSE-2.0

 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
-->
<sample>
    <name>DownloadableFonts</name>
    <group>UI</group>
    <package>com.example.android.downloadablefonts</package>

    <!--
        Lower the minSdk once the API level for O is changed to 26.
        At this moment, an app targeting "O" only runs on O preview devices.
    -->
    <minSdk>"O"</minSdk>

    <strings>
        <intro>
<![CDATA[
This sample demonstrates how to use the Downloadable Fonts feature introduced in Android O.
Downloadable Fonts is a feature that allows apps to request a certain font from a provider
instead of bundling it or downloading it themselves. This means, there is no need to bundle the
font as an asset.

Note that the sample uses Google Play Services as a font provider, which requires pre-released
version of Google Play Services.
You can sign up for the beta program so that the beta version of Google Play Services is
downloaded to your device. https://developers.google.com/android/guides/beta-program
If you have Google Play Services whose version number is equal or above 11.x.x, that means you
have the compatible version installed. (You can confirm by navigating to
Settings -> Apps -> Google Play Services)
]]>
        </intro>
    </strings>

    <template src="base-build" />

    <metadata>
        <status>PUBLISHED</status>
        <categories>UI, Android O Preview</categories>
        <technologies>Android</technologies>
        <languages>Java</languages>
        <solutions>Mobile</solutions>
        <level>INTERMEDIATE</level>
        <icon>screenshots/icon-web.png</icon>
        <screenshots>
            <img>screenshots/screenshot-1.png</img>
        </screenshots>
        <api_refs>
            <android>android.provider.FontRequest</android>
            <android>android.support.v4.provider.FontRequest</android>
            <android>android.provider.FontsContractCompat</android>
            <android>android.support.v4.provider.FontsContractCompat</android>
        </api_refs>

        <description>
<![CDATA[
This sample demonstrates how to use the Downloadable Fonts feature introduced in Android O.
Downloadable Fonts is a feature that allows apps to request a certain font from a provider
instead of bundling it or downloading it themselves. This means, there is no need to bundle the
font as an asset.
]]>
        </description>

        <intro>
<![CDATA[
There are two ways of requesting a font to download.
To request a font to download from Java code, you need to create a [FontRequest][1] class first like
this:
```java
FontRequest request = new FontRequest(
    "com.google.android.gms.fonts", // ProviderAuthority
    "com.google.android.gms",  // ProviderPackage
    query,  // Query
    R.array.com_google_android_gms_fonts_certs); // Certificates
```
The parameters `ProviderAuthority`, `ProviderPackage` are given by a font provider, in the case
above uses Google Play Services as a font provider.
The third parameter is a query string about the requested font. The syntax of the query is defined
by the font provider.

Then pass the request instance to the `requestFont` method in the [FontsContractCompat][2].
```java
FontsContractCompat.requestFont(context, request, callback, handler);
```
The downloaded font or an error code if the request failed will be passed to the callback.
The example above assumes you are using the classes from the support library. There are
corresponding classes in the framework, but the feature is available back to API level 14 if you
use the support library.

You can declare a downloaded font in an XML file and let the system download it for you and use it
in layouts.
```xml
<font-family xmlns:app="http://schemas.android.com/apk/res-auto"
        app:fontProviderAuthority="com.google.android.gms.fonts"
        app:fontProviderPackage="com.google.android.gms"
        app:fontProviderQuery="Lobster Two"
        app:fontProviderCerts="@array/com_google_android_gms_fonts_certs">
</font-family>
```
By defining the requested font in an XML file and putting the `preloaded_fonts` array and the
meta-data tag in the AndroidManifest, you can avoid the delay until the font is downloaded by the
first attempt.
```xml
<resources>
    <array name="preloaded_fonts" translatable="false">
        <item>@font/lobster_two</item>
    </array>
</resources>
```

```xml
<application >
    ...
    <meta-data android:name="preloaded_fonts" android:resource="@array/preloaded_fonts" />
    ...
</application>
```

Note that the sample uses Google Play Services as a font provider, which requires pre-released
version of Google Play Services.
You can sign up for the beta program so that the beta version of Google Play Services is
downloaded to your device. https://developers.google.com/android/guides/beta-program
If you have Google Play Services whose version number is equal or above 11.x.x, that means you
have the compatible version installed. (You can confirm by navigating to
Settings -> Apps -> Google Play Services)

[1]: https://developer.android.com/reference/android/support/v4/provider/FontRequest.html
[2]: https://developer.android.com/reference/android/support/v4/provider/FontsContractCompat.html
]]>
        </intro>
    </metadata>
</sample>