Android：多点触控和TYPE_SYSTEM_OVERLAY [英] Android : Multi touch and TYPE_SYSTEM_OVERLAY

问题描述

我正尝试在系统重叠式视图中获取多个触摸事件，但只接收 MotionEvent.ACTION_OUTSIDE 事件。

I am trying to get multiple touch events on a system overlay view, but am only receiving the MotionEvent.ACTION_OUTSIDE event.

有没有办法在系统覆盖图上获取多个触摸事件？

Is there any possible way of getting multiple touch events on a system overlay?

任何示例或链接非常有帮助。

Any examples or links would be very helpful.

推荐答案

要创建重叠视图，设置 LayoutParams 您需要将类型设置为 TYPE_SYSTEM_OVERLAY 并使用标志 FLAG_WATCH_OUTSIDE_TOUCH 。这会出现一个问题，因为Android文档说明：

To create an overlay view, when setting up the LayoutParams you need to set the type to TYPE_SYSTEM_OVERLAY and use the flag FLAG_WATCH_OUTSIDE_TOUCH. This presents a problem because as the Android documentation states:

你不会收到完整的向下/向上/向上的手势，只有位置第一个下来作为 ACTION_OUTSIDE 。

为了接收完整的数组触摸事件需要使用 TYPE_SYSTEM_ALERT 类型，但这会导致覆盖层覆盖屏幕并停止与其他元素的交互。解决方案是同时使用 TYPE_SYSTEM_OVERLAY 和 TYPE_SYSTEM_ALERT ，并通过更改 LayoutParams

In order to receive the full array of touch events you need to use the TYPE_SYSTEM_ALERT type, but this causes the overlay to take over the screen and stop interaction with other elements. The solution is to use both TYPE_SYSTEM_OVERLAY and TYPE_SYSTEM_ALERT and switch between them by changing the type of the LayoutParams as needed.

这是通过以下方式实现的：

This is accomplished by:

1. 观看 ACTION_OUTSIDE 运动事件。


2. 发生时，测试是否在叠加层内发生。 >
   
3. 如果是，将 LayoutParams 类型切换到 TYPE_SYSTEM_ALERT


4. 与叠加层的交互完成后，切换回 TYPE_SYSTEM_OVERLAY


5. 重复

1. Watch for the ACTION_OUTSIDE motion event.
2. When it occurs, test if it occured within the overlay.
3. If it did, switch the LayoutParams type to TYPE_SYSTEM_ALERT
4. Once the interaction with the overlay is complete, switch back to TYPE_SYSTEM_OVERLAY
5. Repeat

要记住的一件事是， ACTION_OUTSIDE 运动事件总是传递给其余的屏幕上的元素。所以，例如，如果覆盖层位于按钮的顶部，则该按钮也将接收运动事件，并且无法阻止。

The one thing to keep in mind is that the ACTION_OUTSIDE motion event is always passed on to the rest of the elements on the screen. So, for example, if the overlay is on top of a button, that button will also receive the motion event and there is no way to stop it.

还要确保您将 SYSTEM_ALERT_WINDOW 权限添加到mainifest文件。

Also make sure you add the SYSTEM_ALERT_WINDOW permission to the mainifest file.

我已经在这里发布了完整的解决方案：

http://www.jawsware.mobi/code_OverlayView/ （更新）

I've posted the complete solution here:
http://www.jawsware.mobi/code_OverlayView/ (UPDATED)

它包含所有源代码和一个链接，用于下载整个示例项目。

It includes all the source code and a link to download the entire example project.

Android 4.0更新 - 1/3/2013

要创建重叠视图，当设置LayoutParams 不要将类型设置为 TYPE_SYSTEM_OVERLAY

To create an overlay view, when setting up the LayoutParams DON'T set the type to TYPE_SYSTEM_OVERLAY.

相反将其设置为 TYPE_PHONE 。

使用以下标志：

FLAG_NOT_TOUCH_MODAL

FLAG_WATCH_OUTSIDE_TOUCH

FLAG_NOT_TOUCH_MODAL <<我发现这个很重要。没有它，将重点放在覆盖和软键（家庭，菜单等）上，不会传递到下面的活动。

FLAG_NOT_TOUCH_MODAL << I found this one to be quite important. Without it, focus is given to the overlay and soft-key (home, menu, etc.) presses are not passed to the activity below.

此外，以前的链接（上）已更新以反映此更新。

Also, the previous link (above) has been updated to reflect this update.

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