检查一个键是否与Qt关闭 [英] Check if a Key is Down with Qt

问题描述

我在玩一些图形，我用箭头键实现了简单的相机移动。我的第一种方法是重写 keyPressEvent ，这样做：

I am playing around with some graphics, and I have implemented simple camera movement with the arrow keys. My first approach was to override keyPressEvent to do something like this:

switch(key)
{
   case up: MoveCameraForward(step); break;
   case left: MoveCameraLeft(step); break;
   ...
}

将。当我按住例如前进键时，相机向前移动步进单位，然后停止一段时间，然后继续移动。我猜这是事件是如何生成的，以避免在有点长按键情况下的多个事件。

This doesn't work as I wish it would. When I press and hold, for example, the forward key, the camera moves forward "step" units, then halts for a while and then continues moving. I am guessing that this is how the event is generated, in order to avoid multiple events in case of a little bit long keypress.

因此，我需要轮询键盘在我的 Paint（）例程。我还没有找到如何做到与Qt。我想到有一个地图< Key，bool> 将在 keyPressEvent 和 keyReleaseEvent 并在 Paint（）中轮询映射。任何更好的想法？感谢您的任何见解。

So, I need to poll the keyboard in my Paint() routine. I haven't found how to do it with Qt. I thought of having a map<Key, bool> which would be updated in keyPressEvent and keyReleaseEvent and poll that map in Paint(). Any better ideas? Thanks for any insights.

推荐答案

常规。我没有找到
如何做到与Qt。我想到有一张地图，
将更新在keyPressEvent和keyReleaseEvent和投票在
Paint（）。

So, I need to poll the keyboard in my Paint() routine. I haven't found how to do it with Qt. I thought of having a map which would be updated in keyPressEvent and keyReleaseEvent and poll that map in Paint().

你的第二个方法是我会做的，除了我会使用连续的，周期性的QTimer事件来轮询键盘按下的地图，并调用QWidget :: Update（）函数，当有效的显示窗口部件无效。强烈建议在Paint（）内部执行非绘画操作，但我不知道如何解释。

Your second method is what I would have done, except that I would use a continuous, periodic QTimer event to poll the keyboard-pressed map and call QWidget::Update() function when necessary to invalidate the display widget instead. Performing non-painting operations inside Paint() is strongly discouraged for many reasons but I do not know how to explain that well.

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