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Commit a329ffdc authored by smain@google.com's avatar smain@google.com
Browse files

clarifications to the Java 8 dependencies in preview setup. 

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
parent 14381c20

docs/html/preview/download.jd

+25 −20
Original line number Diff line number Diff line
@@ -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>

docs/html/preview/images/studio-jdk-location.jpg

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docs/html/preview/j8-jack.jd

+34 −55
Original line number Diff line number Diff line 
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>
@@ -148,13 +127,15 @@ N</a>.</p> 
  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>
@@ -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>.
 
 No newline at end of file
 
<p>If you find other problems while using Jack, <a href=

"http://tools.android.com/filing-bugs">please report bugs</a>.</p>
 
 No newline at end of file

docs/html/preview/setup-sdk.jd

+31 −23
Original line number Diff line number Diff line
@@ -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>

     ...