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/*
* Copyright (C) 2012 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package android.app;
import static android.view.WindowManager.LayoutParams.INVALID_WINDOW_TYPE;
import static android.view.WindowManager.LayoutParams.TYPE_PRESENTATION;
import static android.view.WindowManager.LayoutParams.TYPE_PRIVATE_PRESENTATION;
import android.annotation.NonNull;
import android.compat.annotation.UnsupportedAppUsage;
import android.content.Context;
import android.content.res.Resources;
import android.hardware.display.DisplayManager;
import android.hardware.display.DisplayManager.DisplayListener;
import android.os.Build;
import android.os.Handler;
import android.os.Looper;
import android.util.TypedValue;
import android.view.ContextThemeWrapper;
import android.view.Display;
import android.view.Gravity;
import android.view.Window;
import android.view.WindowManager;
import android.view.WindowManager.LayoutParams.WindowType;
import java.util.Objects;
/**
* Base class for presentations.
*
* A presentation is a special kind of dialog whose purpose is to present
* content on a secondary display. A {@link Presentation} is associated with
* the target {@link Display} at creation time and configures its context and
* resource configuration according to the display's metrics.
*
* Notably, the {@link Context} of a presentation is different from the context
* of its containing {@link Activity}. It is important to inflate the layout
* of a presentation and load other resources using the presentation's own context
* to ensure that assets of the correct size and density for the target display
* are loaded.
*
* A presentation is automatically canceled (see {@link Dialog#cancel()}) when
* the display to which it is attached is removed. An activity should take
* care of pausing and resuming whatever content is playing within the presentation
* whenever the activity itself is paused or resumed.
*
*
* Choosing a presentation display
*
* Before showing a {@link Presentation} it's important to choose the {@link Display}
* on which it will appear. Choosing a presentation display is sometimes difficult
* because there may be multiple displays attached. Rather than trying to guess
* which display is best, an application should let the system choose a suitable
* presentation display.
*
* There are two main ways to choose a {@link Display}.
*
*
* Using the media router to choose a presentation display
*
* The easiest way to choose a presentation display is to use the
* {@link android.media.MediaRouter MediaRouter} API. The media router service keeps
* track of which audio and video routes are available on the system.
* The media router sends notifications whenever routes are selected or unselected
* or when the preferred presentation display of a route changes.
* So an application can simply watch for these notifications and show or dismiss
* a presentation on the preferred presentation display automatically.
*
* The preferred presentation display is the display that the media router recommends
* that the application should use if it wants to show content on the secondary display.
* Sometimes there may not be a preferred presentation display in which
* case the application should show its content locally without using a presentation.
*
* Here's how to use the media router to create and show a presentation on the preferred
* presentation display using {@link android.media.MediaRouter.RouteInfo#getPresentationDisplay()}.
*
*
* MediaRouter mediaRouter = (MediaRouter) context.getSystemService(Context.MEDIA_ROUTER_SERVICE);
* MediaRouter.RouteInfo route = mediaRouter.getSelectedRoute();
* if (route != null) {
* Display presentationDisplay = route.getPresentationDisplay();
* if (presentationDisplay != null) {
* Presentation presentation = new MyPresentation(context, presentationDisplay);
* presentation.show();
* }
* }
*
* The following sample code from ApiDemos demonstrates how to use the media
* router to automatically switch between showing content in the main activity and showing
* the content in a presentation when a presentation display is available.
*
* {@sample development/samples/ApiDemos/src/com/example/android/apis/app/PresentationWithMediaRouterActivity.java
* activity}
*
* Using the display manager to choose a presentation display
*
* Another way to choose a presentation display is to use the {@link DisplayManager} API
* directly. The display manager service provides functions to enumerate and describe all
* displays that are attached to the system including displays that may be used
* for presentations.
*
* The display manager keeps track of all displays in the system. However, not all
* displays are appropriate for showing presentations. For example, if an activity
* attempted to show a presentation on the main display it might obscure its own content
* (it's like opening a dialog on top of your activity). Creating a presentation on the main
* display will result in {@link android.view.WindowManager.InvalidDisplayException} being thrown
* when invoking {@link #show()}.
*
* Here's how to identify suitable displays for showing presentations using
* {@link DisplayManager#getDisplays(String)} and the
* {@link DisplayManager#DISPLAY_CATEGORY_PRESENTATION} category.
*
*
* DisplayManager displayManager = (DisplayManager) context.getSystemService(Context.DISPLAY_SERVICE);
* Display[] presentationDisplays = displayManager.getDisplays(DisplayManager.DISPLAY_CATEGORY_PRESENTATION);
* if (presentationDisplays.length > 0) {
* // If there is more than one suitable presentation display, then we could consider
* // giving the user a choice. For this example, we simply choose the first display
* // which is the one the system recommends as the preferred presentation display.
* Display display = presentationDisplays[0];
* Presentation presentation = new MyPresentation(context, presentationDisplay);
* presentation.show();
* }
*
* The following sample code from ApiDemos demonstrates how to use the display
* manager to enumerate displays and show content on multiple presentation displays
* simultaneously.
*
* {@sample development/samples/ApiDemos/src/com/example/android/apis/app/PresentationActivity.java
* activity}
*
* @see android.media.MediaRouter#ROUTE_TYPE_LIVE_VIDEO for information on about live
* video routes and how to obtain the preferred presentation display for the
* current media route.
* @see DisplayManager for information on how to enumerate displays and receive
* notifications when displays are added or removed.
*/
public class Presentation extends Dialog {
private static final String TAG = "Presentation";
private final Display mDisplay;
private final DisplayManager mDisplayManager;
private final Handler mHandler = new Handler(Objects.requireNonNull(Looper.myLooper(),
"Presentation must be constructed on a looper thread."));
/**
* Creates a new presentation that is attached to the specified display
* using the default theme.
*
* @param outerContext The context of the application that is showing the presentation.
* The presentation will create its own context (see {@link #getContext()}) based
* on this context and information about the associated display.
* @param display The display to which the presentation should be attached.
*/
public Presentation(Context outerContext, Display display) {
this(outerContext, display, 0);
}
/**
* Creates a new presentation that is attached to the specified display
* using the optionally specified theme.
*
* @param outerContext The context of the application that is showing the presentation.
* The presentation will create its own context (see {@link #getContext()}) based
* on this context and information about the associated display.
* From {@link android.os.Build.VERSION_CODES#S}, the presentation will create its own window
* context based on this context, information about the associated display. Customizing window
* type by {@link Window#setType(int) #getWindow#setType(int)} causes the mismatch of the window
* and the created window context, which leads to
* {@link android.view.WindowManager.InvalidDisplayException} when invoking {@link #show()}.
* @param display The display to which the presentation should be attached.
* @param theme A style resource describing the theme to use for the window.
* See
* Style and Theme Resources for more information about defining and using
* styles. This theme is applied on top of the current theme in
* outerContext. If 0, the default presentation theme will be used.
*/
public Presentation(Context outerContext, Display display, int theme) {
this(outerContext, display, theme, INVALID_WINDOW_TYPE);
}
/**
* Creates a new presentation that is attached to the specified display
* using the optionally specified theme, and override the default window type for the
* presentation.
* @param outerContext The context of the application that is showing the presentation.
* The presentation will create its own context (see {@link #getContext()}) based
* on this context and information about the associated display.
* From {@link android.os.Build.VERSION_CODES#S}, the presentation will create its own window
* context based on this context, information about the associated display and the window type.
* If the window type is not specified, the presentation will choose the default type for the
* presentation.
* @param display The display to which the presentation should be attached.
* @param theme A style resource describing the theme to use for the window.
* See
* Style and Theme Resources for more information about defining and using
* styles. This theme is applied on top of the current theme in
* outerContext. If 0, the default presentation theme will be used.
* @param type Window type.
*
* @hide
*/
public Presentation(@NonNull Context outerContext, @NonNull Display display, int theme,
@WindowType int type) {
super(createPresentationContext(outerContext, display, theme, type), theme, false);
mDisplay = display;
mDisplayManager = getContext().getSystemService(DisplayManager.class);
final Window w = getWindow();
final WindowManager.LayoutParams attr = w.getAttributes();
w.setAttributes(attr);
w.setGravity(Gravity.FILL);
w.setType(getWindowType(type, display));
setCanceledOnTouchOutside(false);
}
private static @WindowType int getWindowType(@WindowType int type, @NonNull Display display) {
if (type != INVALID_WINDOW_TYPE) {
return type;
}
return (display.getFlags() & Display.FLAG_PRIVATE) != 0 ? TYPE_PRIVATE_PRESENTATION
: TYPE_PRESENTATION;
}
/**
* Gets the {@link Display} that this presentation appears on.
*
* @return The display.
*/
public Display getDisplay() {
return mDisplay;
}
/**
* Gets the {@link Resources} that should be used to inflate the layout of this presentation.
* This resources object has been configured according to the metrics of the
* display that the presentation appears on.
*
* @return The presentation resources object.
*/
public Resources getResources() {
return getContext().getResources();
}
@Override
protected void onStart() {
super.onStart();
mDisplayManager.registerDisplayListener(mDisplayListener, mHandler);
}
@Override
protected void onStop() {
mDisplayManager.unregisterDisplayListener(mDisplayListener);
super.onStop();
}
/**
* Inherited from {@link Dialog#show}. Will throw
* {@link android.view.WindowManager.InvalidDisplayException} if the specified secondary
* {@link Display} can't be found or if it does not have {@link Display#FLAG_PRESENTATION} set.
*/
@Override
public void show() {
super.show();
}
/**
* Called by the system when the {@link Display} to which the presentation
* is attached has been removed.
*
* The system automatically calls {@link #cancel} to dismiss the presentation
* after sending this event.
*
* @see #getDisplay
*/
public void onDisplayRemoved() {
}
/**
* Called by the system when the properties of the {@link Display} to which
* the presentation is attached have changed.
*
* @see #getDisplay
*/
public void onDisplayChanged() {
}
private void handleDisplayRemoved() {
onDisplayRemoved();
cancel();
}
private void handleDisplayChanged() {
onDisplayChanged();
}
@UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.R, publicAlternatives = "{@code N/A}")
private static Context createPresentationContext(Context outerContext, Display display,
int theme) {
return createPresentationContext(outerContext, display, theme, INVALID_WINDOW_TYPE);
}
private static Context createPresentationContext(
Context outerContext, Display display, int theme, @WindowType int type) {
if (outerContext == null) {
throw new IllegalArgumentException("outerContext must not be null");
}
if (display == null) {
throw new IllegalArgumentException("display must not be null");
}
Context windowContext = outerContext.createDisplayContext(display)
.createWindowContext(getWindowType(type, display), null /* options */);
if (theme == 0) {
TypedValue outValue = new TypedValue();
windowContext.getTheme().resolveAttribute(
com.android.internal.R.attr.presentationTheme, outValue, true);
theme = outValue.resourceId;
}
return new ContextThemeWrapper(windowContext, theme);
}
private final DisplayListener mDisplayListener = new DisplayListener() {
@Override
public void onDisplayAdded(int displayId) {
}
@Override
public void onDisplayRemoved(int displayId) {
if (displayId == mDisplay.getDisplayId()) {
handleDisplayRemoved();
}
}
@Override
public void onDisplayChanged(int displayId) {
if (displayId == mDisplay.getDisplayId()) {
handleDisplayChanged();
}
}
};
}