目前只在Update有效的原因是
public void Rotate()
{
transform.RotateAround(sun.transform.position, Vector3.up, speed * Time.deltaTime);
}
需要重复调用。否则它只会旋转一帧，Time.deltaTime 的原因只有很小的一部分。但是Button 组件的onClick 事件只触发一次。它类似于例如Input.GetKeyDown 仅在按键按下时调用一次。 Button 组件本身没有实现来处理持续的按钮按下。
据我了解，您想要的是在单击按钮后旋转对象
- 开始永远旋转
- 持续一段时间
- 直到您再次按下按钮
- 直到它被释放（-> 实现一个持续触发按钮，见下文）
单独的Button组件只能做到前三个：
永远旋转
使用Coroutine
private bool isRotating;
public void Rotate()
{
// if aready rotating do nothing
if(isRotating) return;
// start the rotation
StartCoroutine(RotateRoutine());
isRotating = true;
}
private IEnumerator RotateRoutine()
{
// whuut?!
// Don't worry coroutines work a bit different
// the yield return handles that .. never forget it though ;)
while(true)
{
// rotate a bit
transform.RotateAround(sun.transform.position, Vector3.up, speed * Time.deltaTime);
// leave here, render the frame and continue in the next frame
yield return null;
}
}
或者还在Update做这个
private bool isRotating = false;
private void Update()
{
// if not rotating do nothing
if(!isRotating) return;
// rotate a bit
transform.RotateAround(sun.transform.position, Vector3.up, speed * Time.deltaTime);
}
public void Rotate()
{
// enable the rotation
isRotating = true;
}
请注意，Update 解决方案仅供您了解正在发生的事情。不应该那样使用它，因为它效率不高，因为Update 被连续调用，并且如果还没有旋转，也会检查布尔值。这会产生不必要的开销。这同样适用于所有下面的例子：更喜欢使用协程而不是Update（在这种情况下！在其他情况下，使用一个@实际上更好，更有效987654337@ 方法而不是多个并发 Coroutines .. 但这是另一回事。）
旋转一定时间
作为协程
// adjust in the inspector
// how long should rotation carry on (in seconds)?
public float duration = 1;
private bool isAlreadyRotating;
public void Rotate()
{
// if aready rotating do nothing
if(isAlreadyRotating) return;
// start a rottaion
StartCoroutine(RotateRoutine());
}
private IEnumerator RotateRoutine()
{
// set the flag to prevent multiple callse
isAlreadyRotating = true;
float timePassed = 0.0f;
while(timePassed < duration)
{
// rotate a small amount
transform.RotateAround(sun.transform.position, Vector3.up, speed * Time.deltaTime);
// add the time passed since last frame
timePassed += Time.deltaTime;
// leave here, render the frame and continue in the next frame
yield return null;
}
// reset the flag so another rotation might be started again
isAlreadyRotating = false;
}
或Update
public float duration;
private bool isRotating;
private float timer;
private void Update()
{
// if not rotating do nothing
if(!isRotating) return;
// reduce the timer by passed time since last frame
timer -= Time.deltaTime;
// rotate a small amount
transform.RotateAround(sun.transform.position, Vector3.up, speed * Time.deltaTime);
// if the timer is not 0 return
if(timer > 0) return;
// stop rottaing
isRotating = false;
}
public void Rotate()
{
// if already rotating do nothing
if(isRotating) return;
// start rotating
isRotating = true;
// enable timer
timer = duration;
}
切换旋转
这与之前的非常相似，但这次不是计时器，而是通过再次单击来停止旋转。 （您甚至可以将两者结合起来，但要小心正确重置 isRotating 标志；）
作为协程
private bool isRotating;
public void ToggleRotation()
{
// if rotating stop the routine otherwise start one
if(isRotating)
{
StopCoroutine(RotateRoutine());
isRotating = false;
}
else
{
StartCoroutine(RotateRoutine());
isRotating = true;
}
}
private IEnumerator RotateRoutine()
{
// whuut?!
// Don't worry coroutines work a bit different
// the yield return handles that .. never forget it though ;)
while(true)
{
// rotate a bit
transform.RotateAround(sun.transform.position, Vector3.up, speed * Time.deltaTime);
// leave here, render the frame and continue in the next frame
yield return null;
}
}
或Update
private bool isRotating;
private void Update()
{
// if not rotating do nothing
if(!isRottaing) return;
// rotate a bit
transform.RotateAround(sun.transform.position, Vector3.up, speed * Time.deltaTime);
}
public void ToggleRotation()
{
// toggle the flag
isRotating = !isRotating;
}
旋转直到释放
这是最“复杂”的部分，因为单独的Button 无法做到这一点（没有“发布时”）。但是您可以使用IPointerXHandler 接口来实现它。
好消息：您可以保留当前的原始脚本
public void Rotate()
{
transform.RotateAround(sun.transform.position, Vector3.up, speed *
Time.deltaTime);
}
现在您需要按钮的扩展名。它会像Update一样在每一帧重复调用whilePressed事件，所以你只需要在whilePressed中引用你的Rotate方法而不是onClick。
同样有两种选择将其实现为协程：
[RequireComponent(typeof(Button))]
public class HoldableButton : MonoBehaviour, IPointerDownHandler, IPointerUpHandler, IPointerExitHandler
{
// reference the same way as in onClick
public UnityEvent whilePressed;
private Button button;
private bool isPressed;
private void Awake()
{
button = GetComponent<Button>();
if(!button)
{
Debug.LogError("Oh no no Button component on this object :O",this);
}
}
// Handle pointer down
public void OnPointerDown()
{
// skip if the button is not interactable
if(!button.enabled || !button.interactable) return;
// skip if already rotating
if(isPressed) return;
StartCoroutine(PressedRoutine());
isPressed= true;
}
// Handle pointer up
public void OnPointerUp()
{
isPressed= false;
}
// Handle pointer exit
public void OnPointerExit()
{
isPressed= false;
}
private IEnumerator RotateRoutine()
{
// repeatedly call whilePressed until button isPressed turns false
while(isPressed)
{
// break the routine if button was disabled meanwhile
if(!button.enabled || !button.interactable)
{
isPressed = false;
yield break;
}
// call whatever is referenced in whilePressed;
whilePressed.Invoke();
// leave here, render the frame and continue in the next frame
yield return null;
}
}
}
或者你也可以在Update 中再次做同样的事情
[RequireComponent(typeof(Button))]
public class HoldableButton : MonoBehaviour, IPointerDownHandler, IPointerUpHandler, IPointerExitHandler
{
public UnityEvent whilePressed;
private bool isPressed;
private Button button;
private void Awake()
{
button = GetComponent<Button>();
if(!button)
{
Debug.LogError("Oh no no Button component on this object :O",this);
}
}
private void Update()
{
// if button is not interactable do nothing
if(!button.enabled || !button.interactable) return;
// if not rotating do nothing
if(!isPressed) return;
// call whatever is referenced in whilePressed;
whilePressed.Invoke();
}
// Handle pointer down
public void OnPointerDown()
{
// enable pressed
isPressed= true;
}
// Handle pointer up
public void OnPointerUp()
{
// disable pressed
isPressed= false;
}
// Handle pointer exit
public void OnPointerExit()
{
// disable pressed
isPressed= false;
}
}
将此组件放在Button 组件旁边。您不必在onClick 中引用任何内容，只需将其留空即可。而是参考onPressed 中的内容。保留 Button 组件，因为它还为我们处理 UI 样式（例如悬停更改颜色/精灵等）
再次重申：Update 解决方案目前可能看起来更干净/更简单，但不如 Coroutine 解决方案高效（在此用例中）和易于控制（这可能基于意见）。