overview
order before split screen
Task display areas in top down Z order:
TaskDisplayArea DefaultTaskDisplayArea
mPreferredTopFocusableRootTask=Task{
919dc1b #1 type=home ?? U=0 visible=true visibleRequested=true mode=fullscreen translucent=false sz=1}
mLastFocusedRootTask=Task{
919dc1b #1 type=home ?? U=0 visible=true visibleRequested=true mode=fullscreen translucent=false sz=1}
Application tokens in top down Z order:
* Task{
919dc1b #1 type=home ?? U=0 visible=true visibleRequested=true mode=fullscreen translucent=false sz=1}
bounds=[0,0][1080,2520]
* Task{
95cd9f8 #2 type=home I=com.miui.home/.launcher.Launcher U=0 rootTaskId=1 visible=true visibleRequested=true mode=fullscreen translucent=false sz=1}
bounds=[0,0][1080,2520]
* ActivityRecord{
23a7bec u0 com.miui.home/.launcher.Launcher} t2}
* Task{
e49cf5a #27 type=standard A=10219:com.miui.weather2 U=0 visible=false visibleRequested=false mode=fullscreen translucent=true sz=1}
bounds=[0,0][1080,2520]
* ActivityRecord{
4788499 u0 com.miui.weather2/.ActivityWeatherMain} t27}
* Task{
ec94c1a #38 type=undefined ?? U=0 visible=false visibleRequested=false mode=fullscreen translucent=true sz=0}
bounds=[0,0][1080,2520]
* Task{
a07962f #25 type=standard A=10070:android.task.mms U=0 visible=false visibleRequested=false mode=fullscreen translucent=true sz=1}
bounds=[0,0][1080,2520]
* ActivityRecord{
43f400e u0 com.android.mms/.ui.MmsTabActivity} t25}
// 分屏的Task位于TaskDisplayArea的最底部
* Task{
bcbb9ca #39 type=standard ?? U=0 visible=false visibleRequested=false mode=fullscreen translucent=true sz=2}
bounds=[0,0][1080,2520]
* Task{
495d73b #41 type=standard ?? U=0 rootTaskId=39 visible=false visibleRequested=false mode=multi-window translucent=true sz=0}
bounds=[0,1317][1080,2520]
* Task{
65e6135 #40 type=undefined ?? U=0 rootTaskId=39 visible=false visibleRequested=false mode=multi-window translucent=true sz=0}
bounds=[0,0][1080,1289]
order in split screen
Task display areas in top down Z order:
TaskDisplayArea DefaultTaskDisplayArea
mPreferredTopFocusableRootTask=Task{
f555c62 #4 type=standard ?? U=0 visible=true visibleRequested=true mode=fullscreen translucent=false sz=2}
mLastFocusedRootTask=Task{
f555c62 #4 type=standard ?? U=0 visible=true visibleRequested=true mode=fullscreen translucent=false sz=2}
Application tokens in top down Z order:
// reorder分屏相关Task到TaskDisplayArea顶部
* Task{
f555c62 #4 type=standard ?? U=0 visible=true visibleRequested=true mode=fullscreen translucent=false sz=2}
bounds=[0,0][1080,2520]
* Task{
f4a61f3 #6 type=undefined ?? U=0 rootTaskId=4 visible=true visibleRequested=true mode=multi-window translucent=false sz=1}
bounds=[0,1295][1080,2520]
* Task{
9b3720c #80 type=standard A=10213:com.miui.notes U=0 rootTaskId=4 visible=true visibleRequested=true mode=multi-window translucent=false sz=1}
bounds=[0,1295][1080,2520]
* ActivityRecord{
2ab7e0 u0 com.miui.notes/.ui.NotesListActivity} t80}
* Task{
3c50f2d #5 type=standard ?? U=0 rootTaskId=4 visible=true visibleRequested=true mode=multi-window translucent=false sz=1}
bounds=[0,0][1080,1267]
* Task{
27d1129 #78 type=undefined A=10003:com.miui.gallery.home U=0 rootTaskId=4 visible=true visibleRequested=true mode=multi-window translucent=false sz=2}
bounds=[0,0][1080,1267]
* ActivityRecord{
c63706 u0 com.miui.gallery/.activity.GallerySettingsActivity} t78}
* ActivityRecord{
1435ba u0 com.miui.gallery/.activity.HomePageActivity} t78}
* Task{
a48f388 #1 type=home ?? U=0 visible=false visibleRequested=false mode=fullscreen translucent=true sz=1}
bounds=[0,0][1080,2520]
* Task{
e676dd2 #2 type=home I=com.miui.home/.launcher.Launcher U=0 rootTaskId=1 visible=false visibleRequested=false mode=fullscreen translucent=true sz=1}
bounds=[0,0][1080,2520]
* ActivityRecord{
3faca81 u0 com.miui.home/.launcher.Launcher} t2}
* Task{
ad9de1e #3 type=undefined ?? U=0 visible=false visibleRequested=false mode=fullscreen translucent=true sz=0}
bounds=[0,0][1080,2520]
enter split screen
systemui process
The split screen on android T is that after the split screen is confirmed, the desktop process calls the startTasksWithLegacyTransition method of com.android.wm.shell.splitscreen.SplitScreenController.ISplitScreenImpl under the wm shell of the systemui process to start the split screen process.
/**
* The interface for calls from outside the host process.
*/
@BinderThread
private static class ISplitScreenImpl extends ISplitScreen.Stub {
......
@Override
public void startTasksWithLegacyTransition(int mainTaskId, @Nullable Bundle mainOptions,
int sideTaskId, @Nullable Bundle sideOptions, @SplitPosition int sidePosition,
float splitRatio, RemoteAnimationAdapter adapter) {
// binder 线程post 到主线程的executor去执行
executeRemoteCallWithTaskPermission(mController, "startTasks",
(controller) -> controller.mStageCoordinator.startTasksWithLegacyTransition(
mainTaskId, mainOptions, sideTaskId, sideOptions, sidePosition,
splitRatio, adapter));
}
system server process
When entering split screen, the HierarchyOp list of WindowContainerTransaction contains three elements: reorder, startTask, startTask
private void applyTransaction(@NonNull WindowContainerTransaction t, int syncId,
@Nullable Transition transition, @NonNull CallerInfo caller,
@Nullable Transition finishTransition) {
......
// Hierarchy changes
final List<WindowContainerTransaction.HierarchyOp> hops = t.getHierarchyOps();
final int hopSize = hops.size();
if (hopSize > 0) {
final boolean isInLockTaskMode = mService.isInLockTaskMode();
for (int i = 0; i < hopSize; ++i) {
effects |= applyHierarchyOp(hops.get(i), effects, syncId, transition,
isInLockTaskMode, caller, t.getErrorCallbackToken(),
t.getTaskFragmentOrganizer(), finishTransition);
}
}
......
}
exit split screen
systemui process
system server process
When exiting the split screen, the HierarchyOp list of WindowContainerTransaction also contains three elements: childrenTasksReparent, childrenTasksReparent, reorder (fullcscreen task at the outermost layer of the split screen)
{
ChildrenTasksReparent: from=RemoteToken{
6206d89 Task{
495d73b #41 type=standard ?? U=0 rootTaskId=39 visible=true visibleRequested=true mode=multi-window translucent=false sz=1}} to=null mToTop=false mReparentTopOnly=false mWindowingMode=[1, 0, 6] mActivityType=[1]}
{
ChildrenTasksReparent: from=RemoteToken{
1d0a090 Task{
65e6135 #40 type=undefined ?? U=0 rootTaskId=39 visible=true visibleRequested=true mode=multi-window translucent=false sz=1}} to=null mToTop=true mReparentTopOnly=false mWindowingMode=[1, 0, 6] mActivityType=[1]}
{
reorder: RemoteToken{
aae4b1a Task{
bcbb9ca #39 type=standard ?? U=0 visible=true visibleRequested=true mode=fullscreen translucent=false sz=2}} to bottom}
private int reparentChildrenTasksHierarchyOp(WindowContainerTransaction.HierarchyOp hop,
@Nullable Transition transition, int syncId) {
// 一般为分屏的上下屏Task，mode为multi-window
WindowContainer<?> currentParent = hop.getContainer() != null
? WindowContainer.fromBinder(hop.getContainer()) : null;
// 这里一般为null
WindowContainer newParent = hop.getNewParent() != null
? WindowContainer.fromBinder(hop.getNewParent()) : null;
if (currentParent == null && newParent == null) {
throw new IllegalArgumentException("reparentChildrenTasksHierarchyOp: " + hop);
} else if (currentParent == null) {
currentParent = newParent.asTask().getDisplayContent().getDefaultTaskDisplayArea();
} else if (newParent == null) {
// newParent赋值为TaskDisplayArea
newParent = currentParent.asTask().getDisplayContent().getDefaultTaskDisplayArea();
}
......
// We want to collect the tasks first before re-parenting to avoid array shifting on us.
final ArrayList<Task> tasksToReparent = new ArrayList<>();
currentParent.forAllTasks(task -> {
Slog.i(TAG, " Processing task=" + task);
final boolean reparent;
if (task.mCreatedByOrganizer || task.getParent() != finalCurrentParent) {
// We only care about non-organized task that are direct children of the thing we
// are reparenting from.
return false;
}
if (newParentInMultiWindow && !task.supportsMultiWindowInDisplayArea(newParentTda)) {
Slog.e(TAG, "reparentChildrenTasksHierarchyOp non-resizeable task to multi window,"
+ " task=" + task);
return false;
}
if (!ArrayUtils.contains(hop.getActivityTypes(), task.getActivityType())
|| !ArrayUtils.contains(hop.getWindowingModes(), task.getWindowingMode())) {
return false;
}
if (hop.getToTop()) {
tasksToReparent.add(0, task);
} else {
tasksToReparent.add(task);
}
return hop.getReparentTopOnly() && tasksToReparent.size() == 1;
});
final int count = tasksToReparent.size();
for (int i = 0; i < count; ++i) {
final Task task = tasksToReparent.get(i);
if (syncId >= 0) {
addToSyncSet(syncId, task);
}
if (transition != null) transition.collect(task);
// 执行reparent操作
if (newParent instanceof TaskDisplayArea) {
// For now, reparenting to display area is different from other reparents...
task.reparent((TaskDisplayArea) newParent, hop.getToTop());
} else {
task.reparent((Task) newParent,
hop.getToTop() ? POSITION_TOP : POSITION_BOTTOM,
false /*moveParents*/, "processChildrenTaskReparentHierarchyOp");
}
}
if (transition != null) transition.collect(newParent);
return TRANSACT_EFFECTS_LIFECYCLE;
}