From 7fb538cc77b2e42ccf63b7344b28c9e035a0278d Mon Sep 17 00:00:00 2001
From: Scott Main In this document
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For developers, the Android 3.0 preview is available as a downloadable component for the +Android SDK. The downloadable platform includes an Android library and system image, as well as a +set of emulator skins and more. The downloadable platform includes no external libraries.
+ + + + +The sections below provide a technical overview of what's new for developers in Android 3.0, +including new features and changes in the framework API since the previous version.
+ + + + +A fragment is a new framework component that allows you to separate distinct elements of an +activity into self-contained modules that define their own UI and lifecycle. To create a +fragment, you must extend the {@link android.app.Fragment} class and implement several lifecycle +callback methods, similar to an {@link android.app.Activity}. You can then combine multiple +fragments in a single activity to build a multi-pane UI in which each +pane manages its own lifecycle and user inputs.
+ +You can also use a fragment without providing a UI and instead use the fragment as a worker +for the activity, such as to manage the progress of a download that occurs only while the +activity is running.
+ +Additionally:
+ +To manage the fragments in your activity, you must use the {@link +android.app.FragmentManager}, which provides several APIs for interacting with fragments, such +as finding fragments in the activity and popping fragments off the back stack to restore them +after they've been removed or hidden.
+ +To perform transactions, such as add or remove fragments, you must create a {@link +android.app.FragmentTransaction}. You can then call methods such as {@link +android.app.FragmentTransaction#add add()} {@link android.app.FragmentTransaction#remove +remove()}, {@link android.app.FragmentTransaction#replace replace()}. Once you've applied all +the changes you want to perform for the transaction, you must call {@link +android.app.FragmentTransaction#commit commit()} and the system will apply the transaction to +the activity.
+ +For more information about using fragments in your application, read the Fragments developer guide.
+ + + + +The Action Bar is a replacement for the traditional title bar at the top of the activity +window. It includes the application logo in the left corner and also replaces the previous Options +Menu UI with a drop-down list for the menu items. Additionally, the Action Bar allows you +to:
+ +In your XML declaration for the menu item, include the attribute, {@code +android:showAsAction} with a value of {@code "ifRoom"}. When there's enough room in the +Action Bar, the menu item appears directly in the bar. Otherwise, it is placed in the +overflow menu, revealed by the icon on the right side of the Action Bar.
In your XML, include the attribute, {@code android:actionViewLayout} with a layout +resource for the action view, or {@code android:actionViewClass} with the class name of the +widget. Like action items, an action view appears only when there's room for it in the Action +Bar. If there's not enough room, it is placed in the overflow menu and behaves like a regular +menu item (for example, an item can provide a {@link android.widget.SearchView} as an action +view, but when in the overflow menu, selecting the item will activate the search dialog).
+The application logo is automatically assigned the {@code android.R.id.home} ID, +which is delivered to your activity's {@link android.app.Activity#onOptionsItemSelected +onOptionsItemSelected()} callback when tapped. Simply respond to this ID in your callback +method to perform an action such as go to your application's "home" activity.
+If your activity does not respond to the icon action, you should hide it by calling {@link +android.app.ActionBar#setDisplayShowHomeEnabled setDisplayShowHomeEnabled(false)}.
+By default, this is true, so the icon will visually respond when pressed, even if you don't +respond. Thus, you should remove the icon if you don't respond to it.
The Action Bar is standard for all applications that set either the {@code +android:minSdkVersion} or {@code +android:targetSdkVersion} to {@code "Honeycomb"}. (The "Honeycomb" API Level is provisional +and effective only while using the preview SDK—you must change it to the official API +Level when the final SDK becomes available.)
+ +For more information, read the Action +Bar developer guide.
+ + + + +Applications can now copy and paste data (beyond mere text) to and from the system-wide +clipboard. Clipped data can be plain text, a URI, or an intent.
+ +By providing the system access to your data in a content provider, the user can copy complex +content (such as an image or data structure) from your application and paste it into another +application that supports that type of content.
+ +To start using the clipboard, get the global {@link android.content.ClipboardManager} object +by calling {@link android.content.Context#getSystemService getSystemService(CLIPBOARD_SERVICE)}.
+ +To create an item to attach to the clipboard, you need to create a new {@link +android.content.ClipData} object, which holds one or more {@link android.content.ClipData.Item} +objects, each describing a single entity. To create a {@link android.content.ClipData} object with +just one {@link android.content.ClipData.Item}, you can use one of the helper methods such as, +{@link android.content.ClipData#newPlainText newPlainText()}, {@link +android.content.ClipData#newUri newUri()}, and {@link android.content.ClipData#newIntent +newIntent()}, which each return a {@link android.content.ClipData} object pre-loaded with the +appropriate {@link android.content.ClipData.Item}.
+ +To add the {@link android.content.ClipData} to the clipboard, pass it to {@link +android.content.ClipboardManager#setPrimaryClip setPrimaryClip()} for your instance of {@link +android.content.ClipboardManager}.
+ +You can then acquire ("paste") a file from the clipboard by calling {@link +android.content.ClipboardManager#getPrimaryClip()} on the {@link +android.content.ClipboardManager}. Handling the {@link android.content.ClipData} you receive can +be more complicated and you need to be sure you can actually handle the data type.
+ +For more information, see the {@link android.content.ClipData} class reference. You can also see +an example implementation of copy and paste in the NotePad sample application.
+ + + + +New APIs now facilitate the ability for your application to implement drag and drop +functionality in the UI.
+ +To drag a {@link android.view.View} in your activity, call {@link android.view.View#startDrag +startDrag()} on the object, providing a {@link android.content.ClipData} object that represents the +information to drag, a {@link android.view.View.DragShadowBuilder} to facilitate the "shadow" that +the user sees while dragging, and an {@link java.lang.Object} that can share information about the +drag object with views that may receive the object. However,
+ +To accept a drag object (receive the "drop") in a +{@link android.view.View}, register the view with an {@link android.view.View.OnDragListener} by +calling {@link android.view.View#setOnDragListener setOnDragListener()}. When a drag event occurs on +the view, the system calls {@link android.view.View.OnDragListener#onDrag onDrag()} for the {@link +android.view.View.OnDragListener}, which receives a {@link android.view.DragEvent} describing +the type of event has occurred (such as "drag started", "drag ended", and "drop"). The receiving +view can inquire the event type delivered to {@link +android.view.View#onDragEvent onDragEvent()} by calling {@link +android.view.DragEvent#getAction getAction()} on the {@link android.view.DragEvent}.
+ +Although a drag event may carry a {@link android.content.ClipData} object, drag and drop does +not depend on the clipboard. The data being dragged is sent to the system as {@link +android.content.ClipData} and the system sends it to {@link android.view.View} objects in the +{@link android.view.DragEvent}. A drag and drop operation should never put the dragged data on the +clipboard.
+ + + +New {@link android.widget.AbsListView#CHOICE_MODE_MULTIPLE_MODAL} mode for {@link +android.widget.AbsListView#setChoiceMode setChoiceMode()} allows for selecting multiple items +from a {@link android.widget.ListView} and {@link android.widget.GridView}.
+ +To enable multiple-choice selection, call {@link +android.widget.AbsListView#setChoiceMode setChoiceMode(CHOICE_MODE_MULTIPLE_MODAL)} and register a +{@link android.widget.AbsListView.MultiChoiceModeListener} with {@link +android.widget.AbsListView#setMultiChoiceModeListener setMultiChoiceModeListener()}.
+ +When the user performs a long-press on an item, the Action Bar switches to the Multi-choice +Action Mode. The system notifies the {@link android.widget.AbsListView.MultiChoiceModeListener} +when items are selected by calling {@link +android.widget.AbsListView.MultiChoiceModeListener#onItemCheckedStateChanged +onItemCheckedStateChanged()}.
+ +For an example of multiple-choice selection, see the List15.java +class in the API Demos sample application.
+ + + + +New framework APIs facilitate asynchronous loading of data using the {@link +android.content.Loader} class. You can use it in combination with UI components such as views and +fragments to dynamically load data from background threads. The {@link +android.content.CursorLoader} subclass is specially designed to help do so for data queried from +a {@link android.content.ContentResolver}.
+ + + +App widgets can now be more interactive with scrolling list views, grid views, view flippers, and +a new 3D stack widget.
+ +Android 3.0 supports several new widget classes for App Widgets, including:
+You can use the new {@link android.widget.RemoteViewsService} to populate the new remote +collection views ({@link android.widget.GridView}, {@link android.widget.ListView}, and {@link +android.widget.StackView}).
+ +You can also use two new {@link android.appwidget.AppWidgetProviderInfo} fields. The {@link +android.appwidget.AppWidgetProviderInfo#autoAdvanceViewId} field lets you specify the view ID of the +app widget subview, which is auto-advanced by the app widget’s host. The +{@link android.appwidget.AppWidgetProviderInfo#previewImage} field specifies a preview of what the +App Widget looks like and is shown to the user from the widget picker. If this field is not +supplied, the app widget's icon is used for the preview.
+ +Android also provides a new widget preview tool (WidgetPreview), located in the SDK tools. The +tool lets you take a screenshot of your app widget, which you can use to populate the customization +tray.
+ + + + + +The {@link android.app.Notification} APIs have been extended to support more content-rich status +bar notifications, plus a new {@link android.app.Notification.Builder} class allows you to easily +control the notification properties. New features include:
+An all new flexible animation framework that allows you to animate the properties of any object +(View, Drawable, Fragment, Object, anything). It allows you to define many aspects of an animation, +such as:
+You can define these animation aspects, and others, for an object's int, float, and hexadecimal +color values, by default. To animate any other type of value, you tell the system how to calculate +the values for that given type, by implementing the {@link android.animation.TypeEvaluator} +interface.
+ +There are two animators that you can use to animate values of a property: {@link +android.animation.ValueAnimator} and {@link android.animation.ObjectAnimator}. The {@link +android.animation.ValueAnimator} computes the animation values, but is not aware of the specific +object or property that is animated as a result. It simply performs the calculations, and you must +listen for the updates and process the data with your own logic. The {@link +android.animation.ObjectAnimator} is a subclass of {@link android.animation.ValueAnimator} and +allows you to set the object and property to animate, so you do not have to listen for updates.
+ +For more information, see the Animation developer guide.
+ + + + + +Base class for an {@link android.widget.AdapterView} that performs animations when switching +between its views.
Simple {@link android.widget.ViewAnimator} that animates between two or more views that have +been added to it. Only one child is shown at a time. If requested, it can automatically flip between +each child at a regular interval.
Allows users to select dates from a calendar and you can configure the range of dates +available. A user can select a date by tapping on it and can scroll and fling +the calendar to a desired date.
Anchors itself to a host view and displays a list of choices, such as for a list of +suggestions when typing into an {@link android.widget.EditText} view.
Enables the user to select a number from a predefined range. The widget presents an +input field and up and down buttons for selecting a number. Touching the input field shows a +scroll wheel that allows the user to scroll through values or touch again to directly edit the +current value. It also allows you to map from positions to strings, so that +the corresponding string is displayed instead of the position index.
Displays a {@link android.view.Menu} in a modal popup window that's anchored to a view. The popup +appears below the anchor view if there is room, or above it if there is not. If the IME (soft +keyboard) is visible, the popup does not overlap it until it is touched.
Provides a search box that works in conjunction with a search provider (in the same manner as +the traditional search dialog). It +also displays recent query suggestions or custom suggestions as configured by the search +provider. This widget is particularly useful for offering search in the Action Bar.
A view that displays its children in a 3D stack and allows users to discretely swipe through the +children.
Android 3.0 offers an updated set of UI widgets that developers can use to quickly add new types +of content to their applications. The new UI widgets are redesigned for use on larger screens such +as tablets and incorporate the new holographic UI theme. Several new widget types are available, +including a 3D stack, search box, a date/time picker, number picker, stack, calendar View etc. +SearchView, PopupMenu, and others. Most of the redesigned widgets can now be used as remote views in +homescreen widgets. Applications written for earlier versions can inherit the new widget designs and +themes.
+ + + + +The standard system widgets and overall look have been redesigned for use on larger screens +such as tablets and incorporate the new holographic UI theme. These style changes are applied +using the standard style and theme system. +Any application that targets the Android 3.0 platform inherit the holographic theme by default. +However, if your application also applies its own styles, then it will override the holographic +theme, unless you update your styles to inherit them.
+ +To apply the holographic theme to individual activities or to inherit them in your own theme +definitions, you can use one of several new {@link android.R.style#Theme_Holo Theme.Holo} +themes.
+ + + +Android now includes APIs for applications to verify the state of connected Bluetooth A2DP and +headset profile devices. You can initialize the respective {@link +android.bluetooth.BluetoothProfile} by calling {@link +android.bluetooth.BluetoothAdapter#getProfileProxy getProfileProxy()} with either the {@link +android.bluetooth.BluetoothProfile#A2DP} or {@link android.bluetooth.BluetoothProfile#HEADSET} +profile constant and a {@link android.bluetooth.BluetoothProfile.ServiceListener} to receive +callbacks when the client is connected or disconnected.
+ + + + + +You can now enable the OpenGL renderer for your application by setting {@code +android:hardwareAccelerated="true"} in your manifest element's {@code <application>} +element or for individual {@code <activity>} +elements.
+ +This flag helps applications by making them draw faster. This results in smoother animations, +smoother scrolling, and overall better performance and response to user interaction.
Renderscript is a runtime 3D framework that provides both an API for building 3D scenes as well +as a special, platform-independent shader language for maximum performance. Using Renderscript, you +can accelerate graphics operations and data processing. Renderscript is an ideal way to create +high-performance 3D effects for applications, wallpapers, carousels, and more.
New {@link android.media.CamcorderProfile#hasProfile hasProfile()} method and several video +quality profiles, such as {@link android.media.CamcorderProfile#QUALITY_1080P}, {@link +android.media.CamcorderProfile#QUALITY_720P}, {@link +android.media.CamcorderProfile#QUALITY_CIF}, and more, to determine the camcorder quality +profiles.
Camcorder APIs now support the ability to record time lapse video. The {@link +android.media.MediaRecorder#setCaptureRate setCaptureRate()} sets the rate at which frames +should be captured.
The platform includes built-in support for Media/Picture Transfer Protocol (MTP/PTP) over USB, +which lets users easily transfer any type of media files between devices and to a host computer. +Developers can take advantage of this to create applications that let users create or manage files +that they may want to transfer across devices.
The platform includes built-in support for Media/Picture Transfer Protocol (MTP/PTP) over USB, +which lets users easily transfer any type of media files between devices and to a host computer. +Developers can build on this support, creating applications that let users create or manage rich +media files that they may want to transfer or share across devices.
New extensible digital rights management (DRM) framework for checking and enforcing digital +rights. It's implemented in two architectural layers:
+For application developers, the framework offers an abstract, unified API that simplifies the +management of protected content. The API hides the complexity of DRM operations and allows a +consistent operation mode for both protected and unprotected content, and across a variety of DRM +schemes.
+ +For device manufacturers, content owners, and Internet digital media providers the DRM +framework?s plugin API provides a means of adding support for a DRM scheme of choice into the +Android system, for secure enforcement of content protection.
+ +The preview release does not provide any native DRM plug-ins for checking and enforcing digital +rights. However, device manufacturers may ship DRM plug-ins with their devices.
+ +You can find all of the DRM APIs in the {@link android.drm} package.
The Android 3.0 platform delivers an updated version of +the framework API. Because this is a preview of the Android 3.0 API, it uses a provisional API +level of "Honeycomb", instead of an integer identifier, which will be provided when the final SDK +is made available and all APIs are final.
+ +To use APIs introduced in Android 3.0 in your application, you need compile the application
+against the Android library that is provided in the Android 3.0 preview SDK platform and you must
+declare this API Level in your manifest as android:minSdkVersion="Honeycomb", in the
+<uses-sdk> element in the application's manifest.
For more information about using this provisional API Level and setting up your environment +to use the preview SDK, please see the Getting +Started document.
+ + + + +The system image included in the downloadable platform provides these +built-in applications:
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The system image included in the downloadable SDK platform provides a variety of +built-in locales. In some cases, region-specific strings are available for the +locales. In other cases, a default version of the language is used. The +languages that are available in the Android 3.0 system +image are listed below (with language_country/region locale +descriptor).
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Note: The Android platform may support more +locales than are included in the SDK system image. All of the supported locales +are available in the Android Open Source +Project.
+ +The downloadable platform includes the following emulator skin:
+ +For more information about how to develop an application that displays +and functions properly on all Android-powered devices, see Supporting Multiple +Screens.
\ No newline at end of file diff --git a/docs/html/sdk/preview/start.jd b/docs/html/sdk/preview/start.jd new file mode 100644 index 0000000000000..7e816c1600865 --- /dev/null +++ b/docs/html/sdk/preview/start.jd @@ -0,0 +1,265 @@ +page.title=Getting Started with the Android 3.0 Preview +@jd:body + +Welcome to Android 3.0!
+ +Android 3.0 is the next major release of the Android platform and is optimized for tablet +devices. We're offering a preview SDK so you can get a head-start developing +applications for it or simply optimize your existing application for upcoming +tablets.
+ + +The Android 3.0 preview SDK is an early look at the upcoming version of Android 3.0, for +developers only.
+ +The preview SDK includes:
+Be aware that:
+When you have an existing application and you want to maintain compatibility with +older versions of Android.
+When you want to upgrade your application to use APIs introduced in Android 3.0 or + create an all new application targeted to tablet devices.
To start using the Android 3.0 preview SDK, set up your existing Android SDK with the new +platform:
+(If you don't have an existing SDK, download it +now.)
+Because the Android emulator must simulate the ARM instruction set architecture on your +computer and the WXGA screen is significantly larger than what the emulator +normally handles, emulator performance is much slower than usual.
+ +We're working hard to resolve the performance issues and it will improve in future releases. +Unfortunately, the emulator will perform slowly during your trial with the preview SDK. Please +continue to use the emulator to evaluate your application's appearance and functionality on Android +3.0.
+ +Tip: To improve the startup time for the emulator, enable +snapshots for the AVD when you create it with the SDK and AVD Manager (there's a checkbox in +the GUI). Then, start the AVD from the manager and check Launch from snapshot and Save to +snapshot. This way, when you close the emulator, a snapshot of the AVD state is saved and +used to quickly relaunch the AVD next time. However, when you choose to save a snapshot, the +emulator will be slow to close, so you might want to enable Save to +snapshot only for the first time you launch the AVD.
+ + + +If you've already developed an application for Android, there are a few things you can do +to optimize it for a tablet experience, without changing the minimum platform version required (you +don't need to change the manifest {@code minSdkVersion}).
+ +Note: All Android applications are forward-compatible, so +there's nothing you have to do—if your application is a good citizen of the Android +APIs, your app should work fine on devices running Android 3.0. However, in order to provide users +a better experience when running your app on an Android 3.0 tablet, we recommend that you update +your application to adapt to the new system theme and add optimize your application for larger +screens.
+ +Here's what you can do to optimize your application for tablets running Android +3.0:
+ ++<manifest ... > + <uses-sdk android:minSdkVersion="4" + android:targetSdkVersion="Honeycomb" /> + <application ... > + ... + <application> +</manifest> ++
Note: The API Level value "Honeycomb" is a provisional API +Level that is valid only while testing against the preview SDK. You +should not publish your application using this API Level. When the final version of +the Android 3.0 SDK is made available, you must change this value to the real API Level that will be +specified for Android 3.0. For more information, read about Android API Levels.
+By targeting the Android 3.0 platform, the system automatically applies the Holographic theme +to each of your activities, when running on an Android 3.0 device.
+Note: If you've applied themes to your activities already, +they will override the Holographic theme that the system applies when you set the {@code +android:targetSdkVersion} to {@code "Honeycomb"}. +Once the Android 3.0 APIs are finalized and an official API Level is assigned, you can use +the system +version qualifier to provide an alternative theme that's based on the Holographic theme when +your application is running on Android 3.0.
+As discussed in the guide to Supporting Multiple Screens, Android
+2.3 and above support the xlarge resource qualifier, which you should use to supply
+alternative layouts for extra large screens.
By providing alternative layouts for some of your activities when running on extra large +screens, you can improve the user experience of your application on a tablet without using any +new APIs.
+For example, here are some things to consider when creating a new layout for tables:
+In general, always be sure that your application follows the Best Practices +for Screen Independence.
+ + + + +If you want to develop something truly for tablets running Android 3.0, then you need to use new +APIs available in Android 3.0. This section introduces some of the new features that you +should use.
+ +The first thing to do when you create a project with the Android 3.0 preview is set the {@code <uses-sdk>} element to +use {@code "Honeycomb"} for the {@code android:minSdkVersion}. For example:
+ ++<manifest ... > + <uses-sdk android:minSdkVersion="Honeycomb" /> + <application ... > + ... + <application> +</manifest> ++ +
Note: The API Level value "Honeycomb" is a provisional API +Level that is valid only while building and testing against the preview SDK. You +cannot publish your application using this API Level. When the final version of the +Android 3.0 SDK is made available, you must change this value to the real API Level that is +specified for Android 3.0. For more information, read about Android API Levels.
+ +Be sure that the {@code +<uses-sdk>} element appears before the {@code <application>} +element.
+ +By targeting the Android 3.0 platform (and declaring it before {@code <application>}), +the system automatically applies the new Holographic theme to each of your +activities.
+ + + +Additionally, you should decide whether your application is for only tablet devices +(specifically, xlarge devices) or for devices of all sizes that may run Android 3.0.
+ +If your application is only for tablets (xlarge screens; not for mobile +devices/phones), then you should include the {@code +<supports-screens>} element in your manifest with all sizes except for xlarge declared +false. For example:
+ ++<manifest ... > + <uses-sdk android:minSdkVersion="Honeycomb" /> + <supports-screens android:smallScreens="false" + android:normalScreens="false" + android:largeScreens="false" + android:xlargeScreens="true" /> + <application ... > + ... + <application> +</manifest> ++ +
With this declaration, you indicate that your application does not support any screen size except +extra large. External services such as Android Market may use this to filter your application +from devices that do not have an extra large screen.
+ +Otherwise, if you want your application to be available to both small devices (phones) and large +devices (tablets), do not include the {@code +<supports-screens>} element.
+ +To learn more about some of the new APIs, +see the Android 3.0 Platform document.
+