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clarifications to the Java 8 dependencies in preview setup.

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Add JDK location screenshot.
More information about the Emulator 2.0 in the testing doc.
Style edits to the Java 8 features doc.

Change-Id: I0c9c74c1e378f43901bd37e70ea68d9e88720adb
This commit is contained in:
smain@google.com
2016-03-09 00:00:37 -08:00
parent 14381c207f
commit a329ffdc29
4 changed files with 90 additions and 98 deletions
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45
docs/html/preview/download.jd
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@@ -188,14 +188,13 @@ This is the Android SDK Preview License Agreement (the “License Agreement”).
<p>To run the Android N Preview so you can test your apps, you can either
<p>To run the Android N Preview and test your apps, you can either
install the Android N Preview on one of several supported devices or run it on
the Android Emulator.</p>
<p>Simply installing your app onto Android N this way does not require
any changes to your app source code. If, however, you want to update your
app to use new Android N APIs and Java 8 language features,
then you need to download Android Studio 2.1 (preview) as described in
app to use new Android N APIs, see
<a href="{@docRoot}preview/setup-sdk.html">Set Up to Develop for Android N</a>.
@@ -221,22 +220,19 @@ then you need to download Android Studio 2.1 (preview) as described in
<h3 id="ota">Get over-the-air updates</h3>
<p>
You can receive preview versions of Android on compatible devices by
enrolling them in the Android Beta Program. Once you enroll a device in
this program, it receives preview versions of Android over-the-air (OTA).
These updates are automatically downloaded and can installed just like
official updates.
</p>
<p>You can receive over-the-air updates to preview versions of Android by
enrolling your compatible device in the Android Beta Program.
These updates are automatically downloaded and will update your device just like
official system updates.</p>
<p>
For more information on the Android Beta Program and to enroll devices, see
For more information and to enroll your device, see
the <a href="https://g.co/androidbeta">Android Beta Program</a> web site.
</p>
<p class="warning">
<strong>Warning:</strong> If you enroll a device for receiving a preview
version of Android, and then later opt-out of receiving those updates on
<strong>Warning:</strong> If you enroll a device in the Android Beta Program,
then later opt-out of receiving updates on
the device, all user data on that device will be removed.
</p>
@@ -247,7 +243,7 @@ then you need to download Android Studio 2.1 (preview) as described in
the updates yourself, you can download the appropriate system image for your
device from the table below.</p>
<p>The process of installing a system image on a device <em>removes all data
<p>Installing a system image on a device <em>removes all data
from the device</em>, so you should back up your data before installing a
system image.</p>
@@ -355,8 +351,8 @@ preview system image, you must perform another manual installation.
</p>
<p class="warning">
<strong>Warning:</strong> Installing a factory image causes all user data on
the device to be removed.
<strong>Warning:</strong> Just like when flashing a preview image,
installing a factory image removes all user data on the device.
</p>
@@ -364,13 +360,13 @@ preview system image, you must perform another manual installation.
<h2 id="setupAVD">Use the Emulator</h2>
<p>To use the Android Emulator to run the Android N Preview you need to download
the Android N Preview SDK and create a virtual device for the emulator.
</p>
<p>To use the Android Emulator to run the Android N Preview, you need to
download the Android N Preview SDK and create a virtual device for the
emulator.</p>
<p>First, download the Android N Preview SDK as follows (if you
already got it while <a href="{@docRoot}preview/setup-sdk.html">setting up
Android Studio 2.1</a>, you can skip this part):
to develop for Android N</a>, you can skip this part):
<ol>
<li>In Android Studio, open the Settings dialog
@@ -404,12 +400,21 @@ Android Studio 2.1</a>, you can skip this part):
then click <strong>Next</strong>.</li>
<li>Select the <strong>N</strong> system image (with the
<strong>x86</strong> ABI), then click <strong>Next</strong>.
(Only x86 system images are currently supported with the Android Emulator
for the Android N Preview.)
<li>Complete the rest of the AVD configuration and click
<strong>Finish</strong>.</li>
</ol>
<p>You can now launch the Android Emulator with the Android N Preview AVD.</p>
<p class="note"><strong>Note:</strong>
For the best experience in the Android Emulator, install
Android Studio 2.1 Preview, which supports the <a
href="http://tools.android.com/tech-docs/emulator">Android Emulator 2.0 Beta</a>
with much faster performance compared to the Emulator in
Android Studio 1.5.</p>
<p>For more information about creating virtual devices, see <a href=
"{@docRoot}tools/devices/index.html">Managing Virtual Devices</a>.
</p>

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89
docs/html/preview/j8-jack.jd
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@@ -1,61 +1,41 @@
page.title=Using Java 8 Language Features
page.title=Java 8 Language Features
page.keywords="android N", "Java 8", "Jack"
@jd:body
<div id="qv-wrapper">
<div id="qv">
<h2>
In this document
</h2>
<ol>
<li>
<a href="#supported-features">Supported Java 8 Language Features and APIs</a>
</li>
<li>
<a href="#configuration">Enabling Java 8 Features and the Jack Toolchain</a>
</li>
</ol>
<h2>
See also
</h2>
<ol>
<li>
<a class="external-link" href=
"https://source.android.com/source/jack.html">Jack (Java Android Compiler
Kit)</a>
</li>
</ol>
</div>
</div>
<p>Android N introduces support for Java 8 language features
that you can use when developing apps that target the Android N. To start using
these features, you need to download and set up Android Studio 2.1 (preview)
and the Android N Preview SDK, which includes the required Jack toolchain and
updated Android Plugin for Gradle.</p>
<p>If you haven't yet installed the Android N Preview SDK, follow the guide to
<a href="{@docRoot}preview/setup-sdk.html">Set Up to Develop for Android
N</a>.</p>
<p>
This document describes the new language features supported in the Android N
that you can use when developing apps that target Android N.
This page describes the new language features supported in the Android N
Preview, how to properly set up your project to use them, and any known
issues you may encounter.
</p>
<p>To start using these features, you need to download and set up Android
Studio 2.1 (preview) and the Android N Preview SDK, which includes the required
Jack toolchain and updated Android Plugin for Gradle. If you haven't yet
installed the Android N Preview SDK, see <a href=
"{@docRoot}preview/setup-sdk.html">Set Up to Develop for Android N</a>.</p>
<p class="note">
<strong>Note:</strong> Using the new Java 8 language features is not a
requirement for developing apps that target the Android N Preview. After
following the set up instructions in the <a href=
"{@docRoot}preview/setup-sdk.html">Preview guide</a>, you may use
the Java 7 language features already supported by Android 6.0 (API level 23)
and below.
requirement for developing apps that target the Android N platform. If you
don't want to write code with Java 8 language features, you can keep your
project's source and target compatibility values set to Java 7, but you still
must compile with JDK 8 to build against the Android N platform.
</p>
<h2 id="supported-features">
@@ -64,8 +44,8 @@ N</a>.</p>
<p>
Android does not currently support all Java 8 language features. However, the
following features are now available when developing apps targeting the N
Developer Preview:
following features are now available when developing apps targeting the
Android N Preview:
</p>
<ul>
@@ -90,8 +70,7 @@ N</a>.</p>
<p>
Additionally, the following Java 8 language feature APIs are now available
with the Preview:
Additionally, the following Java 8 language feature APIs are now available:
</p>
<ul>
@@ -143,18 +122,20 @@ N</a>.</p>
new <a class="external-link" href=
"https://source.android.com/source/jack.html">Jack toolchain</a>. This new
Android toolchain compiles Java language source into Android-readable dex
bytecode, has its own {@code .jack} library format, and provides most tool chain
bytecode, has its own {@code .jack} library format, and provides most toolchain
features as part of a single tool: repackaging, shrinking, obfuscation and
multidex.
</p>
<p>Here we compare the two toolchains used to build Android DEX files:</p>
<p>Here is a comparison the two toolchains used to build Android DEX files:</p>
<ul>
<li>Legacy: javac ({@code .java} &gt; {@code .class}) &gt; dx ({@code
.class} &gt; {@code .dex})
<li>Legacy javac toolchain:<br>
<b>javac</b> ({@code .java} --&gt; {@code .class}) --&gt; <b>dx</b> ({@code
.class} --&gt; {@code .dex})
</li>
<li>Modern: Jack ({@code .java} &gt; {@code .jack} &gt; {@code .dex})
<li>New Jack toolchain:<br>
<b>Jack</b> ({@code .java} --&gt; {@code .jack} --&gt; {@code .dex})
</li>
</ul>
@@ -169,9 +150,9 @@ N</a>.</p>
<pre>
android {
...
defaultConfig {
...
defaultConfig {
...
jackOptions {
enabled true
}
@@ -192,19 +173,17 @@ android {
with Jack and will be disabled while using the new toolchain.
</p>
<p>
Since Jack does not generate intermediate class files when compiling an app,
tools that depend on these files do not currently work with Jack. Some examples of
these tools are:
</p>
<p>Because Jack does not generate intermediate class files when compiling an
app, tools that depend on these files do not currently work with Jack. Some
examples of these tools are:</p>
<ul>
<li>Lint detectors that operate on class files
</li>
<li>Tools and libraries that require the app’s class files (e.g. JaCoCo and Mockito)
</li>
<li>Tools and libraries that require the app’s class files (such as JaCoCo
and Mockito)</li>
</ul>
If you find other problems while using Jack, <a class="external-link" href=
"http://tools.android.com/filing-bugs">please report bugs</a>.
<p>If you find other problems while using Jack, <a href=
"http://tools.android.com/filing-bugs">please report bugs</a>.</p>

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@@ -25,7 +25,7 @@ page.image=images/cards/card-n-sdk_2x.png
<p>To develop apps for the Android N Preview, you need to make some updates
to your developer environment, as described on this page.</p>
<p>To instead simply test your app's compatibility on the
<p>To simply test your app's compatibility on the
Android N system image, follow the guide to <a
href="{@docRoot}preview/download.html">Test on an Android N Device</a>.</p>
@@ -34,11 +34,14 @@ href="{@docRoot}preview/download.html">Test on an Android N Device</a>.</p>
<h2 id="get-as13">Get Android Studio 2.1 (preview)</h2>
<p>The Android N platform adds support for Java 8 language features,
which are supported only with a new compiler called Jack. The latest Jack
compiler is currently supported only in Android Studio 2.1. So if you want to
use Java 8 language features, then you need to use Android Studio 2.1 to
build your app.
<p>The Android N platform adds support for <a
href="{@docRoot}preview/j8-jack.html">Java 8 language features</a>,
which require a new compiler called Jack. The latest version of Jack
is currently supported only in Android Studio 2.1. So if you want to
use Java 8 language features, you need to use Android Studio 2.1 to
build your app. Otherwise, you don't need to use the Jack compiler, but you
still need to update to JDK 8 to compile against the Android N platform,
as described below.
</p>
<iframe width="400" height="225" src="//www.youtube.com/embed/SBbWGxXCMqQ?autohide=1&amp;showinfo=0" frameborder="0" allowfullscreen="" style="float: right; margin: 0 0 20px 20px;"></iframe>
@@ -47,8 +50,8 @@ build your app.
release channel. If you already
have Android Studio and don't want to update to the canary channel, you can
download Android Studio 2.1 as a separate installation and use it
with Android N, leaving your primary Android Studio environment
unaffected.</p>
for development with Android N, leaving your primary Android Studio
environment unaffected.</p>
<p>To download Android Studio 2.1 as a separate installation, follow these
steps (or if you want to receive Android Studio 2.1 as an update to your
@@ -85,8 +88,8 @@ existing installation, skip to step 4):</p>
Android N Preview SDK in Android Studio as follows:</p>
<ol>
<li>While still viewing the Updates panel from the previous
procedure, select the <strong>Automatically
<li>While still viewing the Updates panel (step 4 from above),
select the <strong>Automatically
check updates for Android SDK</strong> check box and select
<strong>Preview Channel</strong> from the drop-down list.
</li>
@@ -109,7 +112,6 @@ Android N Preview SDK in Android Studio as follows:</p>
</li>
</ol>
<h3 id="docs-dl">Get the N Preview reference documentation</h3>
<p>
@@ -140,25 +142,32 @@ Android N Preview SDK in Android Studio as follows:</p>
<h2 id="java8">Get the Java 8 JDK and JRE</h2>
<p>You also need to update your JDK for Java 8 and install the
Java 8 Runtime Environment (JRE) to run some
tools included in Android Studio 2.1. So, if you don't have the latest
version of each already, download JDK 8 and JRE 8 now.</p>
<p>To compile your app against the Android N platform, you need to use
the Java 8 Developer Kit (JDK 8), and in order to use some tools with Android
Studio 2.1, you need to install the Java 8 Runtime Environment (JRE 8). So, if
you don't have the latest version of each already, download JDK 8 and JRE 8
now.</p>
<p>With Java 8 installed, set the JDK version in Android Studio as follows:</p>
<p>Then set the JDK version in Android Studio as follows:</p>
<ol>
<li>Open an Android project in Android Studio, then open the
Project Structure dialog by selecting <strong>File &gt;
Project Structure</strong>.
Project Structure</strong>. (Alternatively, you can set the default
for all projects by selecting <strong>File &gt; Other Settings &gt;
Default Project Structure</strong>.)
</li>
<li>In the left panel of the dialog, click <strong>SDK Location</strong>.
</li>
<li>In the <strong>JDK Location</strong> field, enter the location of the
Java 8 JDK, then click <strong>OK</strong>.
Java 8 JDK (click the button on the right
to browse your files), then click <strong>OK</strong>.
</li>
</ol>
<img src="{@docRoot}preview/images/studio-jdk-location.jpg" width="700"
alt="" />
<h2 id="create-update">Update or Create a Project</h2>
@@ -166,10 +175,10 @@ Android N Preview SDK in Android Studio as follows:</p>
To use the Android N APIs, your project must be configured appropriately.
</p>
<p>If you plan to use Java 8 language features, you should read
<a href="{@docRoot}preview/j8-jack.html">Using Java 8 Language Features</a>
for information about how to configure your project and the supported
Java 8 features.</p>
<p>If you plan to use Java 8 language features, you should also read
<a href="{@docRoot}preview/j8-jack.html">Java 8 Language Features</a>
for information about the supported Java 8 features and
how to configure your project with the Jack compiler.</p>
<h3 id="update">Update an existing project</h3>
@@ -186,7 +195,6 @@ android {
...
defaultConfig {
...
minSdkVersion <strong>'N'</strong>
targetSdkVersion <strong>'N'</strong>
...