118 lines
4.2 KiB
Markdown
118 lines
4.2 KiB
Markdown
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Android DownloadableFonts Sample
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===================================
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This sample demonstrates how to use the Downloadable Fonts feature introduced in Android O.
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Downloadable Fonts is a feature that allows apps to request a certain font from a provider
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instead of bundling it or downloading it themselves. This means, there is no need to bundle the
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font as an asset.
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Introduction
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------------
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There are two ways of requesting a font to download.
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To request a font to download from Java code, you need to create a [FontRequest][1] class first like
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this:
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```java
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FontRequest request = new FontRequest(
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"com.google.android.gms.fonts", // ProviderAuthority
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"com.google.android.gms", // ProviderPackage
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query, // Query
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R.array.com_google_android_gms_fonts_certs); // Certificates
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```
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The parameters `ProviderAuthority`, `ProviderPackage` are given by a font provider, in the case
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above uses Google Play Services as a font provider.
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The third parameter is a query string about the requested font. The syntax of the query is defined
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by the font provider.
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Then pass the request instance to the `requestFont` method in the [FontsContractCompat][2].
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```java
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FontsContractCompat.requestFont(context, request, callback, handler);
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```
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The downloaded font or an error code if the request failed will be passed to the callback.
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The example above assumes you are using the classes from the support library. There are
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corresponding classes in the framework, but the feature is available back to API level 14 if you
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use the support library.
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You can declare a downloaded font in an XML file and let the system download it for you and use it
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in layouts.
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```xml
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<font-family xmlns:app="http://schemas.android.com/apk/res-auto"
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app:fontProviderAuthority="com.google.android.gms.fonts"
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app:fontProviderPackage="com.google.android.gms"
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app:fontProviderQuery="Lobster Two"
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app:fontProviderCerts="@array/com_google_android_gms_fonts_certs">
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</font-family>
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```
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By defining the requested font in an XML file and putting the `preloaded_fonts` array and the
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meta-data tag in the AndroidManifest, you can avoid the delay until the font is downloaded by the
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first attempt.
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```xml
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<resources>
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<array name="preloaded_fonts" translatable="false">
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<item>@font/lobster_two</item>
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</array>
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</resources>
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```
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```xml
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<application >
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...
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<meta-data android:name="preloaded_fonts" android:resource="@array/preloaded_fonts" />
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...
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</application>
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```
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[1]: https://developer.android.com/reference/android/support/v4/provider/FontRequest.html
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[2]: https://developer.android.com/reference/android/support/v4/provider/FontsContractCompat.html
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Pre-requisites
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--------------
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- Android SDK 27
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- Android Build Tools v27.0.2
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- Android Support Repository
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Screenshots
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-------------
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<img src="screenshots/screenshot-1.png" height="400" alt="Screenshot"/>
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Getting Started
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---------------
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This sample uses the Gradle build system. To build this project, use the
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"gradlew build" command or use "Import Project" in Android Studio.
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Support
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-------
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- Google+ Community: https://plus.google.com/communities/105153134372062985968
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- Stack Overflow: http://stackoverflow.com/questions/tagged/android
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If you've found an error in this sample, please file an issue:
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https://github.com/googlesamples/android-DownloadableFonts
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Patches are encouraged, and may be submitted by forking this project and
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submitting a pull request through GitHub. Please see CONTRIBUTING.md for more details.
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License
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-------
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Copyright 2017 The Android Open Source Project, Inc.
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Licensed to the Apache Software Foundation (ASF) under one or more contributor
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license agreements. See the NOTICE file distributed with this work for
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additional information regarding copyright ownership. The ASF licenses this
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file to you under the Apache License, Version 2.0 (the "License"); you may not
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use this file except in compliance with the License. You may obtain a copy of
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the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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License for the specific language governing permissions and limitations under
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the License.
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