public class Presentation
extends [Dialog](https://developer.android.com/reference/android/app/Dialog.html)
| java.lang.Object |
| ↳ | android.app.Dialog |
| | ↳ | android.app.Presentation |
Presentation的基类。
Presentation 翻译过来为本文中翻译为演示。
Presentation是一种特殊的对话框，其目的是在辅助显示器上演示内容。A 在创建时与Presentation目标关联，Display并根据显示器的指标配置其上下文和资源配置。
值得注意的是，Context演示文稿的与其包含的上下文不同Activity。重要的是要扩大演示文稿的布局并使用演示文稿自己的上下文加载其他资源，以确保加载目标显示的大小和密度正确的资产。
Dialog#cancel()除去 演示文稿所连接的显示器后，该演示文稿将自动取消（请参阅）。每当活动本身暂停或恢复时，活动都应暂停和恢复演示文稿中正在播放的任何内容。
选择演示文稿显示
在显示a之前Presentation，重要的是选择Display它出现的位置。有时很难选择演示文稿显示，因为可能会连接多个显示。应用程序应该让系统选择合适的演示显示，而不是试图猜测哪种显示是最佳的。
有两种主要的选择方法Display。
选择演示文稿显示的最简单方法是使用 MediaRouterAPI。媒体路由器服务跟踪系统上可用的音频和视频路由。每当选择或取消选择路由或路由的首选表示形式发生更改时，媒体路由器都会发送通知。因此，应用程序可以简单地监视这些通知，并自动在首选演示文稿显示上显示或关闭演示文稿。
首选演示文稿显示是媒体路由器建议应用程序在其想要在辅助显示器上显示内容时应使用的显示。有时可能没有首选的演示文稿显示，在这种情况下，应用程序应该在不使用演示文稿的情况下在本地显示其内容。
以下是使用媒体路由器通过来在首选演示文稿显示上创建和显示演示文稿的方法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();
}
}
以下示例代码ApiDemos演示了如何使用媒体路由器在演示文稿显示可用时在主要活动中显示内容和演示文稿中显示内容之间自动切换。
/**
* <h3>Presentation Activity</h3>
*
* <p>
* This demonstrates how to create an activity that shows some content
* on a secondary display using a {@link Presentation}.
* </p><p>
* The activity uses the {@link MediaRouter} API to automatically detect when
* a presentation display is available and to allow the user to control the
* media routes using a menu item. When a presentation display is available,
* we stop showing content in the main activity and instead open up a
* {@link Presentation} on the preferred presentation display. When a presentation
* display is removed, we revert to showing content in the main activity.
* We also write information about displays and display-related events to
* the Android log which you can read using <code>adb logcat</code>.
* </p><p>
* You can try this out using an HDMI or Wifi display or by using the
* "Simulate secondary displays" feature in Development Settings to create a few
* simulated secondary displays. Each display will appear in the list along with a
* checkbox to show a presentation on that display.
* </p><p>
* See also the {@link PresentationActivity} sample which
* uses the low-level display manager to enumerate displays and to show multiple
* simultaneous presentations on different displays.
* </p>
*/
public class PresentationWithMediaRouterActivity extends Activity {
private final String TAG = "PresentationWithMediaRouterActivity";
private MediaRouter mMediaRouter;
private DemoPresentation mPresentation;
private GLSurfaceView mSurfaceView;
private TextView mInfoTextView;
private boolean mPaused;
/**
* Initialization of the Activity after it is first created. Must at least
* call {@link android.app.Activity#setContentView setContentView()} to
* describe what is to be displayed in the screen.
*/
@Override
protected void onCreate(Bundle savedInstanceState) {
// Be sure to call the super class.
super.onCreate(savedInstanceState);
// Get the media router service.
mMediaRouter = (MediaRouter)getSystemService(Context.MEDIA_ROUTER_SERVICE);
// See assets/res/any/layout/presentation_with_media_router_activity.xml for this
// view layout definition, which is being set here as
// the content of our screen.
setContentView(R.layout.presentation_with_media_router_activity);
// Set up the surface view for visual interest.
mSurfaceView = (GLSurfaceView)findViewById(R.id.surface_view);
mSurfaceView.setRenderer(new CubeRenderer(false));
// Get a text view where we will show information about what's happening.
mInfoTextView = (TextView)findViewById(R.id.info);
}
@Override
protected void onResume() {
// Be sure to call the super class.
super.onResume();
// Listen for changes to media routes.
mMediaRouter.addCallback(MediaRouter.ROUTE_TYPE_LIVE_VIDEO, mMediaRouterCallback);
// Update the presentation based on the currently selected route.
mPaused = false;
updatePresentation();
}
@Override
protected void onPause() {
// Be sure to call the super class.
super.onPause();
// Stop listening for changes to media routes.
mMediaRouter.removeCallback(mMediaRouterCallback);
// Pause rendering.
mPaused = true;
updateContents();
}
@Override
protected void onStop() {
// Be sure to call the super class.
super.onStop();
// Dismiss the presentation when the activity is not visible.
if (mPresentation != null) {
Log.i(TAG, "Dismissing presentation because the activity is no longer visible.");
mPresentation.dismiss();
mPresentation = null;
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Be sure to call the super class.
super.onCreateOptionsMenu(menu);
// Inflate the menu and configure the media router action provider.
getMenuInflater().inflate(R.menu.presentation_with_media_router_menu, menu);
MenuItem mediaRouteMenuItem = menu.findItem(R.id.menu_media_route);
MediaRouteActionProvider mediaRouteActionProvider =
(MediaRouteActionProvider)mediaRouteMenuItem.getActionProvider();
mediaRouteActionProvider.setRouteTypes(MediaRouter.ROUTE_TYPE_LIVE_VIDEO);
// Return true to show the menu.
return true;
}
private void updatePresentation() {
// Get the current route and its presentation display.
MediaRouter.RouteInfo route = mMediaRouter.getSelectedRoute(
MediaRouter.ROUTE_TYPE_LIVE_VIDEO);
Display presentationDisplay = route != null ? route.getPresentationDisplay() : null;
// Dismiss the current presentation if the display has changed.
if (mPresentation != null && mPresentation.getDisplay() != presentationDisplay) {
Log.i(TAG, "Dismissing presentation because the current route no longer "
+ "has a presentation display.");
mPresentation.dismiss();
mPresentation = null;
}
// Show a new presentation if needed.
if (mPresentation == null && presentationDisplay != null) {
Log.i(TAG, "Showing presentation on display: " + presentationDisplay);
mPresentation = new DemoPresentation(this, presentationDisplay);
mPresentation.setOnDismissListener(mOnDismissListener);
try {
mPresentation.show();
} catch (WindowManager.InvalidDisplayException ex) {
Log.w(TAG, "Couldn't show presentation! Display was removed in "
+ "the meantime.", ex);
mPresentation = null;
}
}
// Update the contents playing in this activity.
updateContents();
}
private void updateContents() {
// Show either the content in the main activity or the content in the presentation
// along with some descriptive text about what is happening.
if (mPresentation != null) {
mInfoTextView.setText(getResources().getString(
R.string.presentation_with_media_router_now_playing_remotely,
mPresentation.getDisplay().getName()));
mSurfaceView.setVisibility(View.INVISIBLE);
mSurfaceView.onPause();
if (mPaused) {
mPresentation.getSurfaceView().onPause();
} else {
mPresentation.getSurfaceView().onResume();
}
} else {
mInfoTextView.setText(getResources().getString(
R.string.presentation_with_media_router_now_playing_locally,
getWindowManager().getDefaultDisplay().getName()));
mSurfaceView.setVisibility(View.VISIBLE);
if (mPaused) {
mSurfaceView.onPause();
} else {
mSurfaceView.onResume();
}
}
}
private final MediaRouter.SimpleCallback mMediaRouterCallback =
new MediaRouter.SimpleCallback() {
@Override
public void onRouteSelected(MediaRouter router, int type, RouteInfo info) {
Log.d(TAG, "onRouteSelected: type=" + type + ", info=" + info);
updatePresentation();
}
@Override
public void onRouteUnselected(MediaRouter router, int type, RouteInfo info) {
Log.d(TAG, "onRouteUnselected: type=" + type + ", info=" + info);
updatePresentation();
}
@Override
public void onRoutePresentationDisplayChanged(MediaRouter router, RouteInfo info) {
Log.d(TAG, "onRoutePresentationDisplayChanged: info=" + info);
updatePresentation();
}
};
/**
* Listens for when presentations are dismissed.
*/
private final DialogInterface.OnDismissListener mOnDismissListener =
new DialogInterface.OnDismissListener() {
@Override
public void onDismiss(DialogInterface dialog) {
if (dialog == mPresentation) {
Log.i(TAG, "Presentation was dismissed.");
mPresentation = null;
updateContents();
}
}
};
/**
* The presentation to show on the secondary display.
* <p>
* Note that this display may have different metrics from the display on which
* the main activity is showing so we must be careful to use the presentation's
* own {@link Context} whenever we load resources.
* </p>
*/
private final static class DemoPresentation extends Presentation {
private GLSurfaceView mSurfaceView;
public DemoPresentation(Context context, Display display) {
super(context, display);
}
@Override
protected void onCreate(Bundle savedInstanceState) {
// Be sure to call the super class.
super.onCreate(savedInstanceState);
// Get the resources for the context of the presentation.
// Notice that we are getting the resources from the context of the presentation.
Resources r = getContext().getResources();
// Inflate the layout.
setContentView(R.layout.presentation_with_media_router_content);
// Set up the surface view for visual interest.
mSurfaceView = (GLSurfaceView)findViewById(R.id.surface_view);
mSurfaceView.setRenderer(new CubeRenderer(false));
}
public GLSurfaceView getSurfaceView() {
return mSurfaceView;
}
}
}
选择演示文稿显示的另一种方法是DisplayManager直接使用API。显示管理器服务提供了枚举和描述连接到系统的所有显示的功能，包括可用于演示的显示。
显示管理器跟踪系统中的所有显示。但是，并非所有的显示都适合显示演示文稿。例如，如果某个活动试图在主显示屏上显示演示文稿，那么它可能会掩盖其自身的内容（就像在活动顶部打开一个对话框一样）。
这是如何识别合适的显示器，以使用DisplayManager#getDisplays(String)和 DisplayManager#DISPLAY_CATEGORY_PRESENTATION类别显示演示文稿 。
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();
}
下面的示例代码ApiDemos演示了如何使用显示管理器枚举显示并同时在多个演示文稿显示中显示内容。
/**
* <h3>Presentation Activity</h3>
*
* <p>
* This demonstrates how to create an activity that shows some content
* on a secondary display using a {@link Presentation}.
* </p><p>
* The activity uses the {@link DisplayManager} API to enumerate displays.
* When the user selects a display, the activity opens a {@link Presentation}
* on that display. We show a different photograph in each presentation
* on a unique background along with a label describing the display.
* We also write information about displays and display-related events to
* the Android log which you can read using <code>adb logcat</code>.
* </p><p>
* You can try this out using an HDMI or Wifi display or by using the
* "Simulate secondary displays" feature in Development Settings to create a few
* simulated secondary displays. Each display will appear in the list along with a
* checkbox to show a presentation on that display.
* </p><p>
* See also the {@link PresentationWithMediaRouterActivity} sample which
* uses the media router to automatically select a secondary display
* on which to show content based on the currently selected route.
* </p>
*/
public class PresentationActivity extends Activity
implements OnCheckedChangeListener, OnClickListener, OnItemSelectedListener {
private final String TAG = "PresentationActivity";
// Key for storing saved instance state.
private static final String PRESENTATION_KEY = "presentation";
// The content that we want to show on the presentation.
private static final int[] PHOTOS = new int[] {
R.drawable.frantic,
R.drawable.photo1, R.drawable.photo2, R.drawable.photo3,
R.drawable.photo4, R.drawable.photo5, R.drawable.photo6,
R.drawable.sample_4,
};
private DisplayManager mDisplayManager;
private DisplayListAdapter mDisplayListAdapter;
private CheckBox mShowAllDisplaysCheckbox;
private ListView mListView;
private int mNextImageNumber;
// List of presentation contents indexed by displayId.
// This state persists so that we can restore the old presentation
// contents when the activity is paused or resumed.
private SparseArray<DemoPresentationContents> mSavedPresentationContents;
// List of all currently visible presentations indexed by display id.
private final SparseArray<DemoPresentation> mActivePresentations =
new SparseArray<DemoPresentation>();
/**
* Initialization of the Activity after it is first created. Must at least
* call {@link android.app.Activity#setContentView setContentView()} to
* describe what is to be displayed in the screen.
*/
@Override
protected void onCreate(Bundle savedInstanceState) {
// Be sure to call the super class.
super.onCreate(savedInstanceState);
// Restore saved instance state.
if (savedInstanceState != null) {
mSavedPresentationContents =
savedInstanceState.getSparseParcelableArray(PRESENTATION_KEY);
} else {
mSavedPresentationContents = new SparseArray<DemoPresentationContents>();
}
// Get the display manager service.
mDisplayManager = (DisplayManager)getSystemService(Context.DISPLAY_SERVICE);
// See assets/res/any/layout/presentation_activity.xml for this
// view layout definition, which is being set here as
// the content of our screen.
setContentView(R.layout.presentation_activity);
// Set up checkbox to toggle between showing all displays or only presentation displays.
mShowAllDisplaysCheckbox = (CheckBox)findViewById(R.id.show_all_displays);
mShowAllDisplaysCheckbox.setOnCheckedChangeListener(this);
// Set up the list of displays.
mDisplayListAdapter = new DisplayListAdapter(this);
mListView = (ListView)findViewById(R.id.display_list);
mListView.setAdapter(mDisplayListAdapter);
}
@Override
protected void onResume() {
// Be sure to call the super class.
super.onResume();
// Update our list of displays on resume.
mDisplayListAdapter.updateContents();
// Restore presentations from before the activity was paused.
final int numDisplays = mDisplayListAdapter.getCount();
for (int i = 0; i < numDisplays; i++) {
final Display display = mDisplayListAdapter.getItem(i);
final DemoPresentationContents contents =
mSavedPresentationContents.get(display.getDisplayId());
if (contents != null) {
showPresentation(display, contents);
}
}
mSavedPresentationContents.clear();
// Register to receive events from the display manager.
mDisplayManager.registerDisplayListener(mDisplayListener, null);
}
@Override
protected void onPause() {
// Be sure to call the super class.
super.onPause();
// Unregister from the display manager.
mDisplayManager.unregisterDisplayListener(mDisplayListener);
// Dismiss all of our presentations but remember their contents.
Log.d(TAG, "Activity is being paused. Dismissing all active presentation.");
for (int i = 0; i < mActivePresentations.size(); i++) {
DemoPresentation presentation = mActivePresentations.valueAt(i);
int displayId = mActivePresentations.keyAt(i);
mSavedPresentationContents.put(displayId, presentation.mContents);
presentation.dismiss();
}
mActivePresentations.clear();
}
@Override
protected void onSaveInstanceState(Bundle outState) {
// Be sure to call the super class.
super.onSaveInstanceState(outState);
outState.putSparseParcelableArray(PRESENTATION_KEY, mSavedPresentationContents);
}
/**
* Shows a {@link Presentation} on the specified display.
*/
private void showPresentation(Display display, DemoPresentationContents contents) {
final int displayId = display.getDisplayId();
if (mActivePresentations.get(displayId) != null) {
return;
}
Log.d(TAG, "Showing presentation photo #" + contents.photo
+ " on display #" + displayId + ".");
DemoPresentation presentation = new DemoPresentation(this, display, contents);
presentation.show();
presentation.setOnDismissListener(mOnDismissListener);
mActivePresentations.put(displayId, presentation);
}
/**
* Hides a {@link Presentation} on the specified display.
*/
private void hidePresentation(Display display) {
final int displayId = display.getDisplayId();
DemoPresentation presentation = mActivePresentations.get(displayId);
if (presentation == null) {
return;
}
Log.d(TAG, "Dismissing presentation on display #" + displayId + ".");
presentation.dismiss();
mActivePresentations.delete(displayId);
}
/**
* Sets the display mode of the {@link Presentation} on the specified display
* if it is already shown.
*/
private void setPresentationDisplayMode(Display display, int displayModeId) {
final int displayId = display.getDisplayId();
DemoPresentation presentation = mActivePresentations.get(displayId);
if (presentation == null) {
return;
}
presentation.setPreferredDisplayMode(displayModeId);
}
private int getNextPhoto() {
final int photo = mNextImageNumber;
mNextImageNumber = (mNextImageNumber + 1) % PHOTOS.length;
return photo;
}
/**
* Called when the show all displays checkbox is toggled or when
* an item in the list of displays is checked or unchecked.
*/
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
if (buttonView == mShowAllDisplaysCheckbox) {
// Show all displays checkbox was toggled.
mDisplayListAdapter.updateContents();
} else {
// Display item checkbox was toggled.
final Display display = (Display)buttonView.getTag();
if (isChecked) {
DemoPresentationContents contents = new DemoPresentationContents(getNextPhoto());
showPresentation(display, contents);
} else {
hidePresentation(display);
}
mDisplayListAdapter.updateContents();
}
}
/**
* Called when the Info button next to a display is clicked to show information
* about the display.
*/
@Override
public void onClick(View v) {
Context context = v.getContext();
AlertDialog.Builder builder = new AlertDialog.Builder(context);
final Display display = (Display)v.getTag();
Resources r = context.getResources();
AlertDialog alert = builder
.setTitle(r.getString(
R.string.presentation_alert_info_text, display.getDisplayId()))
.setMessage(display.toString())
.setNeutralButton(R.string.presentation_alert_dismiss_text,
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
}
})
.create();
alert.show();
}
/**
* Called when a display mode has been selected.
*/
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
final Display display = (Display)parent.getTag();
final Display.Mode[] modes = display.getSupportedModes();
setPresentationDisplayMode(display, position >= 1 && position <= modes.length ?
modes[position - 1].getModeId() : 0);
}
/**
* Called when a display mode has been unselected.
*/
@Override
public void onNothingSelected(AdapterView<?> parent) {
final Display display = (Display)parent.getTag();
setPresentationDisplayMode(display, 0);
}
/**
* Listens for displays to be added, changed or removed.
* We use it to update the list and show a new {@link Presentation} when a
* display is connected.
*
* Note that we don't bother dismissing the {@link Presentation} when a
* display is removed, although we could. The presentation API takes care
* of doing that automatically for us.
*/
private final DisplayManager.DisplayListener mDisplayListener =
new DisplayManager.DisplayListener() {
@Override
public void onDisplayAdded(int displayId) {
Log.d(TAG, "Display #" + displayId + " added.");
mDisplayListAdapter.updateContents();
}
@Override
public void onDisplayChanged(int displayId) {
Log.d(TAG, "Display #" + displayId + " changed.");
mDisplayListAdapter.updateContents();
}
@Override
public void onDisplayRemoved(int displayId) {
Log.d(TAG, "Display #" + displayId + " removed.");
mDisplayListAdapter.updateContents();
}
};
/**
* Listens for when presentations are dismissed.
*/
private final DialogInterface.OnDismissListener mOnDismissListener =
new DialogInterface.OnDismissListener() {
@Override
public void onDismiss(DialogInterface dialog) {
DemoPresentation presentation = (DemoPresentation)dialog;
int displayId = presentation.getDisplay().getDisplayId();
Log.d(TAG, "Presentation on display #" + displayId + " was dismissed.");
mActivePresentations.delete(displayId);
mDisplayListAdapter.notifyDataSetChanged();
}
};
/**
* List adapter.
* Shows information about all displays.
*/
private final class DisplayListAdapter extends ArrayAdapter<Display> {
final Context mContext;
public DisplayListAdapter(Context context) {
super(context, R.layout.presentation_list_item);
mContext = context;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
final View v;
if (convertView == null) {
v = ((Activity) mContext).getLayoutInflater().inflate(
R.layout.presentation_list_item, null);
} else {
v = convertView;
}
final Display display = getItem(position);
final int displayId = display.getDisplayId();
DemoPresentation presentation = mActivePresentations.get(displayId);
DemoPresentationContents contents = presentation != null ?
presentation.mContents : null;
if (contents == null) {
contents = mSavedPresentationContents.get(displayId);
}
CheckBox cb = (CheckBox)v.findViewById(R.id.checkbox_presentation);
cb.setTag(display);
cb.setOnCheckedChangeListener(PresentationActivity.this);
cb.setChecked(contents != null);
TextView tv = (TextView)v.findViewById(R.id.display_id);
tv.setText(v.getContext().getResources().getString(
R.string.presentation_display_id_text, displayId, display.getName()));
Button b = (Button)v.findViewById(R.id.info);
b.setTag(display);
b.setOnClickListener(PresentationActivity.this);
Spinner s = (Spinner)v.findViewById(R.id.modes);
Display.Mode[] modes = display.getSupportedModes();
if (contents == null || modes.length == 1) {
s.setVisibility(View.GONE);
s.setAdapter(null);
} else {
ArrayAdapter<String> modeAdapter = new ArrayAdapter<String>(mContext,
android.R.layout.simple_list_item_1);
s.setVisibility(View.VISIBLE);
s.setAdapter(modeAdapter);
s.setTag(display);
s.setOnItemSelectedListener(PresentationActivity.this);
modeAdapter.add("<default mode>");
for (Display.Mode mode : modes) {
modeAdapter.add(String.format("Mode %d: %dx%d/%.1ffps",
mode.getModeId(),
mode.getPhysicalWidth(), mode.getPhysicalHeight(),
mode.getRefreshRate()));
if (contents.displayModeId == mode.getModeId()) {
s.setSelection(modeAdapter.getCount() - 1);
}
}
}
return v;
}
/**
* Update the contents of the display list adapter to show
* information about all current displays.
*/
public void updateContents() {
clear();
String displayCategory = getDisplayCategory();
Display[] displays = mDisplayManager.getDisplays(displayCategory);
addAll(displays);
Log.d(TAG, "There are currently " + displays.length + " displays connected.");
for (Display display : displays) {
Log.d(TAG, " " + display);
}
}
private String getDisplayCategory() {
return mShowAllDisplaysCheckbox.isChecked() ? null :
DisplayManager.DISPLAY_CATEGORY_PRESENTATION;
}
}
/**
* The presentation to show on the secondary display.
*
* Note that the presentation display may have different metrics from the display on which
* the main activity is showing so we must be careful to use the presentation's
* own {@link Context} whenever we load resources.
*/
private final class DemoPresentation extends Presentation {
final DemoPresentationContents mContents;
public DemoPresentation(Context context, Display display,
DemoPresentationContents contents) {
super(context, display);
mContents = contents;
}
/**
* Sets the preferred display mode id for the presentation.
*/
public void setPreferredDisplayMode(int modeId) {
mContents.displayModeId = modeId;
WindowManager.LayoutParams params = getWindow().getAttributes();
params.preferredDisplayModeId = modeId;
getWindow().setAttributes(params);
}
@Override
protected void onCreate(Bundle savedInstanceState) {
// Be sure to call the super class.
super.onCreate(savedInstanceState);
// Get the resources for the context of the presentation.
// Notice that we are getting the resources from the context of the presentation.
Resources r = getContext().getResources();
// Inflate the layout.
setContentView(R.layout.presentation_content);
final Display display = getDisplay();
final int displayId = display.getDisplayId();
final int photo = mContents.photo;
// Show a caption to describe what's going on.
TextView text = (TextView)findViewById(R.id.text);
text.setText(r.getString(R.string.presentation_photo_text,
photo, displayId, display.getName()));
// Show a n image for visual interest.
ImageView image = (ImageView)findViewById(R.id.image);
image.setImageDrawable(r.getDrawable(PHOTOS[photo]));
GradientDrawable drawable = new GradientDrawable();
drawable.setShape(GradientDrawable.RECTANGLE);
drawable.setGradientType(GradientDrawable.RADIAL_GRADIENT);
// Set the background to a random gradient.
Point p = new Point();
getDisplay().getSize(p);
drawable.setGradientRadius(Math.max(p.x, p.y) / 2);
drawable.setColors(mContents.colors);
findViewById(android.R.id.content).setBackground(drawable);
}
}
/**
* Information about the content we want to show in the presentation.
*/
private final static class DemoPresentationContents implements Parcelable {
final int photo;
final int[] colors;
int displayModeId;
public static final Creator<DemoPresentationContents> CREATOR =
new Creator<DemoPresentationContents>() {
@Override
public DemoPresentationContents createFromParcel(Parcel in) {
return new DemoPresentationContents(in);
}
@Override
public DemoPresentationContents[] newArray(int size) {
return new DemoPresentationContents[size];
}
};
public DemoPresentationContents(int photo) {
this.photo = photo;
colors = new int[] {
((int) (Math.random() * Integer.MAX_VALUE)) | 0xFF000000,
((int) (Math.random() * Integer.MAX_VALUE)) | 0xFF000000 };
}
private DemoPresentationContents(Parcel in) {
photo = in.readInt();
colors = new int[] { in.readInt(), in.readInt() };
displayModeId = in.readInt();
}
@Override
public int describeContents() {
return 0;
}
@Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeInt(photo);
dest.writeInt(colors[0]);
dest.writeInt(colors[1]);
dest.writeInt(displayModeId);
}
}
}
也可以看看：
