218 lines
12 KiB
Plaintext
218 lines
12 KiB
Plaintext
page.title=Creating an Android Project
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page.tags=project setup
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helpoutsWidget=true
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trainingnavtop=true
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next.title=Running Your App
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next.link=running-app.html
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@jd:body
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<!-- This is the training bar -->
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<div id="tb-wrapper">
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<div id="tb">
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<h2>This lesson teaches you to</h2>
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<ol>
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<li><a href="#Studio">Create a Project with Android Studio</a></li>
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<li><a href="#CommandLine">Create a Project with Command Line Tools</a></li>
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</ol>
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<h2>You should also read</h2>
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<ul>
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<li><a href="{@docRoot}tools/projects/index.html">Managing Projects</a></li>
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</ul>
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</div>
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</div>
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<p>An Android project contains all the files that comprise the source code for your Android
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app.</p>
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<p>This lesson
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shows how to create a new project either using Android Studio or using the
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SDK tools from a command line.</p>
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<p class="note"><strong>Note:</strong> You should already have the Android SDK installed, and if
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you're using Android Studio, you should also have <a href="{@docRoot}sdk/installing/studio.html">
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Android Studio</a> installed. If you don't have these, follow the guide to <a
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href="{@docRoot}sdk/installing/index.html">Installing the Android SDK</a> before you start this
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lesson.</p>
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<h2 id="Studio">Create a Project with Android Studio</h2>
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<ol>
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<li>In Android Studio, create a new project:
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<ul>
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<li>If you don't have a project opened, in the <strong>Welcome</strong> screen, click <strong>
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New Project</strong>.</li>
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<li>If you have a project opened, from the <strong>File</strong> menu, select <strong>New
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Project</strong>.</li>
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</ul>
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</li>
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<div class="figure" style="width:420px">
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<img src="{@docRoot}images/training/firstapp/studio-setup-1.png" alt="" />
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<p class="img-caption"><strong>Figure 1.</strong> Configuring a new project in Android Studio.</p>
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</div>
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<li>Under <strong>Configure your new project</strong>, fill in the fields as shown in figure 1
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and click <strong>Next</strong>.
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<p>It will probably be easier to follow these lessons if you use the same values as shown.</p>
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<ul>
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<li><strong>Application Name</strong> is the app name that appears to users.
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For this project, use "My First App."</li>
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<li><strong>Company domain</strong> provides a qualifier that will be appended to the package
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name; Android Studio will remember this qualifier for each new project you create.</li>
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<li><strong>Package name</strong> is the fully qualified name for the project (following the
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same rules as those for naming packages in the Java programming language). Your package name
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must be unique across all packages installed on the Android system. You can <strong>
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Edit</strong> this value independently from the application name or the company
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domain.</li>
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<li><strong>Project location</strong> is the directory on your system that holds the project
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files.</li>
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</ul>
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</li>
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<li>Under <strong>Select the form factors your app will run on</strong>, check the box for <strong>
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Phone and Tablet</strong>.</li>
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<li>For <strong>Minimum SDK</strong>, select <strong>API 8: Android 2.2 (Froyo)</strong>.
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<p>The Minimum Required SDK is the earliest version of Android that your app supports,
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indicated using the <a href="{@docRoot}guide/topics/manifest/uses-sdk-element.html#ApiLevels">
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API level</a>. To support as many devices as possible, you should set this to the lowest
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version available that allows your app to provide its core feature set. If any feature of your
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app is possible only on newer versions of Android and it's not critical to the app's core
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feature set, you can enable the feature only when running on the versions that support it (as
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discussed in <a href="{@docRoot}training/basics/supporting-devices/platforms.html">
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Supporting Different Platform Versions</a>).</p></li>
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<li>Leave all of the other options (TV, Wear, and Glass) unchecked and click <strong>Next.</strong></li>
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<div class="sidebox-wrapper">
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<div class="sidebox">
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<h3>Activities</h3>
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<p>An activity is one of the distinguishing features of the Android framework. Activities
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provide the user with access to your app, and there may be many activities. An application
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will usually have a main activity for when the user launches the application, another
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activity for when she selects some content to view, for example, and other activities for
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when she performs other tasks within the app. See <a href="{@docRoot}guide/components/activities.html">
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Activities</a> for more information.</p>
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</div>
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</div>
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<li>Under <strong>Add an activity to <<em>template</em>></strong>, select <strong>Blank
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Activity</strong> and click <strong>Next</strong>.</li>
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<li>Under <strong>Choose options for your new file</strong>, change the
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<strong>Activity Name</strong> to <em>MyActivity</em>. The <strong>Layout Name</strong> changes
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to <em>activity_my</em>, and the <strong>Title</strong> to <em>MyActivity</em>. The
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<strong>Menu Resource Name</strong> is <em>menu_my</em>.
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<li>Click the <strong>Finish</strong> button to create the project.</li>
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</ol>
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<p>Your Android project is now a basic "Hello World" app that contains some default files. Take a
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moment to review the most important of these:</p>
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<dl>
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<dt><code>app/src/main/res/layout/activity_my.xml</code></dt>
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<dd>This is the XML layout file for the activity you added when you created the project with Android
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Studio. Following the New Project workflow, Android Studio presents this file with both a text
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view and a preview of the screen UI. The file includes some default settings and a <code>TextView</code>
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element that displays the message, "Hello world!"</dd>
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<dt><code>app/src/main/java/com.mycompany.myfirstapp/MyActivity.java</code></dt>
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<dd>A tab for this file appears in Android Studio when the New Project workflow finishes. When you
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select the file you see the class definition for the activity you created. When you build and
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run the app, the {@link android.app.Activity} class starts the activity and loads the layout file
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that says "Hello World!"</dd>
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<dt><code>app/src/main/AndroidManifest.xml</code></dt>
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<dd>The <a href="{@docRoot}guide/topics/manifest/manifest-intro.html">manifest file</a> describes
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the fundamental characteristics of the app and defines each of its components. You'll revisit
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this file as you follow these lessons and add more components to your app.</dd>
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<dt><code>app/build.gradle</code></dt>
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<dd>Android Studio uses Gradle to compile and build your app. There is a <code>build.gradle</code>
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file for each module of your project, as well as a <code>build.gradle</code> file for the entire
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project. Usually, you're only interested in the <code>build.gradle</code> file for the module,
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in this case the <code>app</code> or application module. This is where your app's build dependencies
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are set, including the <code>defaultConfig</code> settings:
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<ul>
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<li><code>compiledSdkVersion</code> is the platform version against which you will compile
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your app. By default, this is set to the latest version of Android available in your SDK.
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(It should be Android 4.1 or greater; if you don't have such a version available, you must
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install one using the <a href="{@docRoot}sdk/installing/adding-packages.html">SDK Manager</a>.)
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You can still build your app to support older versions, but setting this to the latest
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version allows you to enable new features and optimize your app for a great user experience
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on the latest devices.</li>
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<li><code>applicationId</code> is the fully qualified package name for your application that
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you specified during the New Project workflow.</li>
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<li><code>minSdkVersion</code> is the Minimum SDK version you specified during the New Project
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workflow. This is the earliest version of the Android SDK that your app supports.</li>
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<li><code>targetSdkVersion</code> indicates the highest version of Android with which you have
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tested your application. As new versions of Android become available, you should
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test your app on the new version and update this value to match the latest API level and
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thereby take advantage of new platform features. For more information, read
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<a href="{@docRoot}training/basics/supporting-devices/platforms.html">Supporting Different
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Platform Versions</a>.</li>
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</ul>
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<p>See <a href="{@docRoot}sdk/installing/studio-build.html">Building Your Project with Gradle</a>
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for more information about Gradle.</p></dd>
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</dl>
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<p>Note also the <code>/res</code> subdirectories that contain the
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<a href="{@docRoot}guide/topics/resources/overview.html">resources</a> for your application:</p>
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<dl>
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<dt><code>drawable<em><density></em>/</code></dt>
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<dd>Directories for drawable objects (such as bitmaps) that are designed for various densities,
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such as medium-density (mdpi) and high-density (hdpi) screens. Other drawable directories
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contain assets designed for other screen densities.
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Here you'll find the ic_launcher.png that appears when you run the default app.</dd>
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<dt><code>layout/</code></dt>
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<dd>Directory for files that define your app's user interface like activity_my.xml,
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discussed above, which describes a basic layout for the MyActivity class.</dd>
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<dt><code>menu/</code></dt>
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<dd>Directory for files that define your app's menu items.</dd>
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<dt><code>values/</code></dt>
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<dd>Directory for other XML files that contain a collection of resources, such as
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string and color definitions. The strings.xml file defines the "Hello world!" string that
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displays when you run the default app.</dd>
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</dl>
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<p>To run the app, continue to the <a href="running-app.html">next lesson</a>.</p>
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<h2 id="CommandLine">Create a Project with Command Line Tools</h2>
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<p>If you're not using the Android Studio IDE, you can instead create your project
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using the SDK tools from a command line:</p>
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<ol>
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<li>Change directories into the Android SDK’s <code>sdk/</code> path.</li>
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<li>Execute:
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<pre class="no-pretty-print">tools/android list targets</pre>
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<p>This prints a list of the available Android platforms that you’ve downloaded for your SDK. Find
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the platform against which you want to compile your app. Make a note of the target ID. We
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recommend that you select the highest version possible. You can still build your app to
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support older versions, but setting the build target to the latest version allows you to optimize
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your app for the latest devices.</p>
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<p>If you don't see any targets listed, you need to
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install some using the Android SDK
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Manager tool. See <a href="{@docRoot}sdk/installing/adding-packages.html">Adding SDK
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Packages</a>.</p></li>
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<li>Execute:
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<pre class="no-pretty-print">
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android create project --target <target-id> --name MyFirstApp \
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--path <path-to-workspace>/MyFirstApp --activity MyActivity \
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--package com.example.myfirstapp
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</pre>
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<p>Replace <code><target-id></code> with an ID from the list of targets (from the previous step)
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and replace
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<code><path-to-workspace></code> with the location in which you want to save your Android
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projects.</p></li>
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</ol>
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<p class="note"><strong>Tip:</strong> Add the <code>platform-tools/</code> as well as the
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<code>tools/</code> directory to your <code>PATH</code> environment variable.</p>
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<p>Your Android project is now a basic "Hello World" app that contains some default files.
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To run the app, continue to the <a href="running-app.html">next lesson</a>.</p>
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