项目中在给页面做转场动画的时候，用 windowAnimationStyle还是 overridePendingTransition 退出动画都无效的，无意间发发现同事把启动模式改为 singleInstance ，
singleInstance 属于栈动画切换，所以你需要设置的是你栈动画过度效果， overridePendingTransition 的退出只作用栈。 可以看下主题默认动画，taskCloseEnterAnimation taskCloseExitAnimation 可以为singleInstance 特定动画
<style name="Animation.Activity">
<item name="activityOpenEnterAnimation">@anim/activity_open_enter</item>
<item name="activityOpenExitAnimation">@anim/activity_open_exit</item>
<item name="activityCloseEnterAnimation">@anim/activity_close_enter</item>
<item name="activityCloseExitAnimation">@anim/activity_close_exit</item>
<item name="taskOpenEnterAnimation">@anim/task_open_enter</item>
<item name="taskOpenExitAnimation">@anim/task_open_exit</item>
<item name="launchTaskBehindTargetAnimation">@anim/launch_task_behind_target</item>
<item name="launchTaskBehindSourceAnimation">@anim/launch_task_behind_source</item>
<item name="taskCloseEnterAnimation">@anim/task_close_enter</item>
<item name="taskCloseExitAnimation">@anim/task_close_exit</item>
<item name="taskToFrontEnterAnimation">@anim/task_open_enter</item>
<item name="taskToFrontExitAnimation">@anim/task_open_exit</item>
<item name="taskToBackEnterAnimation">@anim/task_close_enter</item>
<item name="taskToBackExitAnimation">@anim/task_close_exit</item>
<item name="wallpaperOpenEnterAnimation">@anim/wallpaper_open_enter</item>
<item name="wallpaperOpenExitAnimation">@anim/wallpaper_open_exit</item>
<item name="wallpaperCloseEnterAnimation">@anim/wallpaper_close_enter</item>
<item name="wallpaperCloseExitAnimation">@anim/wallpaper_close_exit</item>
<item name="wallpaperIntraOpenEnterAnimation">@anim/wallpaper_intra_open_enter</item>
<item name="wallpaperIntraOpenExitAnimation">@anim/wallpaper_intra_open_exit</item>
<item name="wallpaperIntraCloseEnterAnimation">@anim/wallpaper_intra_close_enter</item>
<item name="wallpaperIntraCloseExitAnimation">@anim/wallpaper_intra_close_exit</item>
<item name="fragmentOpenEnterAnimation">@animator/fragment_open_enter</item>
<item name="fragmentOpenExitAnimation">@animator/fragment_open_exit</item>
<item name="fragmentCloseEnterAnimation">@animator/fragment_close_enter</item>
<item name="fragmentCloseExitAnimation">@animator/fragment_close_exit</item>
<item name="fragmentFadeEnterAnimation">@animator/fragment_fade_enter</item>
<item name="fragmentFadeExitAnimation">@animator/fragment_fade_exit</item>
</style>
