Android 9.0以前关闭过渡动画效果只需要把开发者模式中过渡动画缩放设为0就可以。也就是把def_window_transition_scale改为0%
frameworks/base/packages/SettingsProvider/res/values/defaults.xml
+ <fraction name="def_window_transition_scale">100%</fraction>
- <fraction name="def_window_transition_scale">0%</fraction>
9.0以后按这种方式修改后屏幕会闪一下黑屏，整个窗口会抖动一下，感觉动画没有完全关闭。
跟下流程发现还是有些不一样的地方。
void startActivityLocked(ActivityRecord r, ActivityRecord focusedTopActivity,
boolean newTask, boolean keepCurTransition, ActivityOptions options) {
TaskRecord rTask = r.getTask();
final int taskId = rTask.taskId;
// mLaunchTaskBehind tasks get placed at the back of the task stack.
if (!r.mLaunchTaskBehind && (taskForIdLocked(taskId) == null || newTask)) {
// Last activity in task had been removed or ActivityManagerService is reusing task.
// Insert or replace.
// Might not even be in.
insertTaskAtTop(rTask, r);
}
TaskRecord task = null;
if (!newTask) {
// If starting in an existing task, find where that is...
boolean startIt = true;
for (int taskNdx = mTaskHistory.size() - 1; taskNdx >= 0; --taskNdx) {
task = mTaskHistory.get(taskNdx);
if (task.getTopActivity() == null) {
// All activities in task are finishing.
continue;
}
if (task == rTask) {
// Here it is! Now, if this is not yet visible to the
// user, then just add it without starting; it will
// get started when the user navigates back to it.
if (!startIt) {
if (DEBUG_ADD_REMOVE) Slog.i(TAG, "Adding activity " + r + " to task "
+ task, new RuntimeException("here").fillInStackTrace());
r.createWindowContainer();
ActivityOptions.abort(options);
return;
}
break;
} else if (task.numFullscreen > 0) {
startIt = false;
}
}
}
// Place a new activity at top of stack, so it is next to interact with the user.
// If we are not placing the new activity frontmost, we do not want to deliver the
// onUserLeaving callback to the actual frontmost activity
final TaskRecord activityTask = r.getTask();
if (task == activityTask && mTaskHistory.indexOf(task) != (mTaskHistory.size() - 1)) {
mStackSupervisor.mUserLeaving = false;
if (DEBUG_USER_LEAVING) Slog.v(TAG_USER_LEAVING,
"startActivity() behind front, mUserLeaving=false");
}
task = activityTask;
// Slot the activity into the history stack and proceed
if (DEBUG_ADD_REMOVE) Slog.i(TAG, "Adding activity " + r + " to stack to task " + task,
new RuntimeException("here").fillInStackTrace());
// TODO: Need to investigate if it is okay for the controller to already be created by the
// time we get to this point. I think it is, but need to double check.
// Use test in b/34179495 to trace the call path.
if (r.getWindowContainerController() == null) {
r.createWindowContainer();
}
task.setFrontOfTask();
if (!isHomeOrRecentsStack() || numActivities() > 0) {
if (DEBUG_TRANSITION) Slog.v(TAG_TRANSITION,
"Prepare open transition: starting " + r);
//app设置FLAG_ACTIVITY_NO_ANIMATION，主动禁用过渡动画
if ((r.intent.getFlags() & Intent.FLAG_ACTIVITY_NO_ANIMATION) != 0) {
mWindowManager.prepareAppTransition(TRANSIT_NONE, keepCurTransition);
mStackSupervisor.mNoAnimActivities.add(r);
} else {
int transit = TRANSIT_ACTIVITY_OPEN;
if (newTask) {
if (r.mLaunchTaskBehind) {
transit = TRANSIT_TASK_OPEN_BEHIND;
} else {
// If a new task is being launched, then mark the existing top activity as
// supporting picture-in-picture while pausing only if the starting activity
// would not be considered an overlay on top of the current activity
// (eg. not fullscreen, or the assistant)
if (canEnterPipOnTaskSwitch(focusedTopActivity,
null /* toFrontTask */, r, options)) {
focusedTopActivity.supportsEnterPipOnTaskSwitch = true;
}
transit = TRANSIT_TASK_OPEN;
}
}
//准备过渡动画
mWindowManager.prepareAppTransition(transit, keepCurTransition);
mStackSupervisor.mNoAnimActivities.remove(r);
}
boolean doShow = true;
if (newTask) {
// Even though this activity is starting fresh, we still need
// to reset it to make sure we apply affinities to move any
// existing activities from other tasks in to it.
// If the caller has requested that the target task be
// reset, then do so.
if ((r.intent.getFlags() & Intent.FLAG_ACTIVITY_RESET_TASK_IF_NEEDED) != 0) {
resetTaskIfNeededLocked(r, r);
doShow = topRunningNonDelayedActivityLocked(null) == r;
}
} else if (options != null && options.getAnimationType()
== ActivityOptions.ANIM_SCENE_TRANSITION) {
doShow = false;
}
if (r.mLaunchTaskBehind) {
// Don't do a starting window for mLaunchTaskBehind. More importantly make sure we
// tell WindowManager that r is visible even though it is at the back of the stack.
r.setVisibility(true);
ensureActivitiesVisibleLocked(null, 0, !PRESERVE_WINDOWS);
} else if (SHOW_APP_STARTING_PREVIEW && doShow) {
// Figure out if we are transitioning from another activity that is
// "has the same starting icon" as the next one. This allows the
// window manager to keep the previous window it had previously
// created, if it still had one.
TaskRecord prevTask = r.getTask();
ActivityRecord prev = prevTask.topRunningActivityWithStartingWindowLocked();
if (prev != null) {
// We don't want to reuse the previous starting preview if:
// (1) The current activity is in a different task.
if (prev.getTask() != prevTask) {
prev = null;
}
// (2) The current activity is already displayed.
else if (prev.nowVisible) {
prev = null;
}
}
r.showStartingWindow(prev, newTask, isTaskSwitch(r, focusedTopActivity));
}
} else {
// If this is the first activity, don't do any fancy animations,
// because there is nothing for it to animate on top of.
ActivityOptions.abort(options);
}
}
最终通过调用next.setVisibility(true)，调用到AppWindowToken中的setVisibility方法中把要切换的activity设为可见状态。
boolean setVisibility(WindowManager.LayoutParams lp,
boolean visible, int transit, boolean performLayout, boolean isVoiceInteraction) {
boolean delayed = false;
inPendingTransaction = false;
// Reset the state of mHiddenSetFromTransferredStartingWindow since visibility is actually
// been set by the app now.
mHiddenSetFromTransferredStartingWindow = false;
// Allow for state changes and animation to be applied if:
// * token is transitioning visibility state
// * or the token was marked as hidden and is exiting before we had a chance to play the
// transition animation
// * or this is an opening app and windows are being replaced.
boolean visibilityChanged = false;
if (isHidden() == visible || (isHidden() && mIsExiting) || (visible && waitingForReplacement())) {
final AccessibilityController accessibilityController = mService.mAccessibilityController;
boolean changed = false;
if (DEBUG_APP_TRANSITIONS) Slog.v(TAG_WM,
"Changing app " + this + " hidden=" + isHidden() + " performLayout=" + performLayout);
boolean runningAppAnimation = false;
if (transit != WindowManager.TRANSIT_UNSET) {
//使用动画，9.0之前该方法实现是在WindowManagerService中
if (applyAnimationLocked(lp, transit, visible, isVoiceInteraction)) {
delayed = runningAppAnimation = true;
}
final WindowState window = findMainWindow();
//TODO (multidisplay): Magnification is supported only for the default display.
if (window != null && accessibilityController != null
&& getDisplayContent().getDisplayId() == DEFAULT_DISPLAY) {
accessibilityController.onAppWindowTransitionLocked(window, transit);
}
changed = true;
}
...
看下applyAnimationLocked，有这样一段代码
boolean applyAnimationLocked(WindowManager.LayoutParams lp, int transit, boolean enter,
boolean isVoiceInteraction) {
//判断是否已禁用TransationAnimation
if (mService.mDisableTransitionAnimation || !shouldAnimate(transit)) {
if (DEBUG_APP_TRANSITIONS || DEBUG_ANIM) {
Slog.v(TAG_WM, "applyAnimation: transition animation is disabled or skipped."
+ " atoken=" + this);
}
cancelAnimation();
return false;
}
// Only apply an animation if the display isn't frozen. If it is frozen, there is no reason
...
接着看WindowManagerService
WindowManagerService(Context context, InputManagerService inputManager,
boolean haveInputMethods, boolean showBootMsgs, boolean onlyCore,
WindowManagerPolicy policy) {
installLock(this, INDEX_WINDOW);
mContext = context;
mHaveInputMethods = haveInputMethods;
mAllowBootMessages = showBootMsgs;
mOnlyCore = onlyCore;
mLimitedAlphaCompositing = context.getResources().getBoolean(
com.android.internal.R.bool.config_sf_limitedAlpha);
mHasPermanentDpad = context.getResources().getBoolean(
com.android.internal.R.bool.config_hasPermanentDpad);
mInTouchMode = context.getResources().getBoolean(
com.android.internal.R.bool.config_defaultInTouchMode);
mDrawLockTimeoutMillis = context.getResources().getInteger(
com.android.internal.R.integer.config_drawLockTimeoutMillis);
mAllowAnimationsInLowPowerMode = context.getResources().getBoolean(
com.android.internal.R.bool.config_allowAnimationsInLowPowerMode);
mMaxUiWidth = context.getResources().getInteger(
com.android.internal.R.integer.config_maxUiWidth);
//直接读取config
mDisableTransitionAnimation = context.getResources().getBoolean(
com.android.internal.R.bool.config_disableTransitionAnimation);
mInputManager = inputManager; // Must be before createDisplayContentLocked.
mDisplayManagerInternal = LocalServices.getService(DisplayManagerInternal.class);
mDisplaySettings = new DisplaySettings();
mDisplaySettings.readSettingsLocked();
最后尝试把config_disableTransitionAnimation改为true，验证过渡动画关闭并且没有闪屏。