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

问题描述

我试图在系统叠加视图上获得多个触摸事件，但我只收到 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.

有没有办法在系统叠加层上获取多个触摸事件?

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

任何示例或链接都会非常有帮助.

Any examples or links would be very helpful.

推荐答案

要创建叠加视图，在设置LayoutParams时需要将类型设置为TYPE_SYSTEM_OVERLAY并使用标志 FLAG_WATCH_OUTSIDE_TOUCH.这带来了一个问题，因为正如 Android 文档所述:

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:

您不会收到完整的向下/移动/向上手势，只会收到第一个向下的位置作为 ACTION_OUTSIDE.

you will not receive the full down/move/up gesture, only the location of the first down as an ACTION_OUTSIDE.

为了接收完整的触摸事件数组，您需要使用 TYPE_SYSTEM_ALERT 类型，但这会导致覆盖层接管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，并根据需要通过更改LayoutParams 的类型在它们之间进行切换.

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.

这是通过以下方式完成的:

This is accomplished by:

1. 注意 ACTION_OUTSIDE 动作事件.
2. 当它发生时，测试它是否发生在覆盖层内.
3. 如果是，请将 LayoutParams 类型切换为 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 动作事件总是传递给屏幕上的其余元素.因此，例如，如果叠加层位于按钮的顶部，则该按钮也将接收到动作事件并且无法阻止它.

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.

还要确保将 SYSTEM_ALERT_WINDOW 权限添加到 mainifest 文件中.

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)

它包括所有源代码和下载整个示例项目的链接.

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

Android 4.0 更新 - 2013 年 1 月 3 日

要创建叠加视图，请在设置 LayoutParams 时不要将类型设置为 TYPE_SYSTEM_OVERLAY.

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

改为将其设置为 TYPE_PHONE.

使用以下标志:

FLAG_NOT_TOUCH_MODAL

FLAG_WATCH_OUTSIDE_TOUCH

FLAG_NOT_TOUCH_MODAL <<我发现这一点非常重要.没有它，焦点将放在覆盖层上，并且软键(主页、菜单等)按下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，之前的链接(上方)已更新以反映此更新.

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