Jsoup，HTTPClient，HttpURLConnection。(Jsoup, HTTPClient, HttpURLConnection. How to get a response html, if the server always returns a 413 error code)

 就可访问的API而言，听起来你已经找到了相关的点点滴滴。 如果您还没有，请阅读此stackoverflow项目 。 
 
 使用Choreographer和外推，您可以猜测下一次显示刷新的时间。 在Android 5.0+设备上使用eglPresentationTimeANDROID() ，您可以在需要将特定帧发送到显示器时告诉SurfaceFlinger。 假设SurfaceFlinger正确考虑了所有延迟（例如“智能”面板添加的额外帧），那么应该可以获得可靠的时序。 
 
 （请记住，时间基于显示器锁定下一帧的时间，而不是下一帧在显示器上完全可见时...时间延迟取决于面板。） 
 
 Grafika的 “预定交换”活动使用此功能，但听起来你已经熟悉了。 
 
 当它进行交换时，显示器发出信号的唯一方法是从前一帧中dup() display dup() display-retire fence fd，然后等待它。 SurfaceFlinger中的一些代码执行此操作，特别是DispSync监视退役围栏以查看软件“VSYNC”是否正在漂移。 没有用于围栏的公共API，并且用户空间响应时间肯定可能超过1毫秒......它通常比预先做好反应更好。 您对非root用户非自定义设备的要求会导致此问题。 
 
 如果您大多看到正确的行为，但偶尔会看到错过，您最好的选择是使用systrace来追踪原因。 

As far as accessible APIs go, it sounds like you've found the relevant bits and pieces. If you haven't yet, please read through this stackoverflow item.
 
Using Choreographer and extrapolation, you can guess at when the next display refresh will occur. Using eglPresentationTimeANDROID() on an Android 5.0+ device, you can tell SurfaceFlinger when you want a particular frame to be sent to the display. Assuming SurfaceFlinger is properly accounting for all latency (such as additional frames added by "smart" panels), that should get you reliable timing.
 
(Bear in mind that the timing is based on when the display latches the next frame, not when the next frame is fully visible on the display... the latency there will depend on the panel.)
 
Grafika's "scheduled swap" Activity uses this feature, but it sounds like you're already familiar.
 
The only way to get signaled by the display when it does the swap would be to dup() the display-retire fence fd from the previous frame, and wait on it. Some of the code in SurfaceFlinger does this, notably DispSync watches the retire fences to see if the software "VSYNC" is drifting. There is no public API for fences, and the user-space response time could certainly be more than 1ms anyway... it usually works out better to schedule ahead than it does to react. Your requirement for non-rooted non-custom devices makes this problematic.
 
If you're mostly seeing correct behavior, but occasionally seeing a miss, your best bet is to use systrace to track down the cause.