按钮

介绍

The button class is a derived class of the controller class. It provides access to controller button states and button event callbacks.

A button object is accessed through a controller object. It is not constructed directly.

使用权

The controller class provides the following button objects. Each object is an instance of the button class.

目的	用法示例	描述
ButtonEDown	Controller.ButtonEDown.pressing()	E ▼ 按钮。
ButtonEUp	Controller.ButtonEUp.pressing()	E ▲ 按钮。
ButtonFDown	Controller.ButtonFDown.pressing()	F ▼ 按钮。
ButtonFUp	Controller.ButtonFUp.pressing()	F ▲ 按钮。
ButtonL3	Controller.ButtonL3.pressing()	左摇杆按钮。仅适用于 IQ（第二代）控制器。
ButtonLDown	Controller.ButtonLDown.pressing()	L ▼ 按钮。
ButtonLUp	Controller.ButtonLUp.pressing()	L ▲ 按钮。
ButtonR3	Controller.ButtonR3.pressing()	右摇杆按钮。仅适用于 IQ（第二代）控制器。
ButtonRDown	Controller.ButtonRDown.pressing()	R ▼ 按钮。
ButtonRUp	Controller.ButtonRUp.pressing()	R ▲ 按钮。

笔记

• Before using a button member function, create a controller object.

• ButtonL3 and ButtonR3 are only available on the IQ (2nd gen) Controller.

// Create a controller object
controller Controller = controller();

成员功能

The button class includes the following member functions:

Getter — 读取按钮状态。

• pressing — Returns whether the button is being pressed.

回调函数——当按钮事件发生时运行的函数。

• pressed — Registers a function to run when the button is pressed.

• released — Registers a function to run when the button is released.

Getter

紧迫

pressing returns whether the button is currently being pressed.

可用功能

bool pressing() const;

参数

此函数没有参数。

返回值

返回布尔值。

• true — The button is being pressed.

• false — The button is not being pressed.

例子

// Turn right while R Up is pressed
while (true) {
  if (Controller.ButtonRUp.pressing()) {
    Drivetrain.turn(right);
  }
  else {
    Drivetrain.stop();
  }

  wait(20, msec);
}

回调函数

按下

pressed registers a function that runs when the button is pressed.

可用功能

void pressed(void (* callback)(void)) const;

范围	类型	描述
callback	void (*)(void)	按钮按下时运行的函数。

返回值

此函数不返回值。

例子

Define the callback function outside of main.

// Drive forward when F Up is pressed
void driveForward() {
  Drivetrain.driveFor(forward, 100, mm);
}

Register the callback inside main.

int main() {
  vexcodeInit();

  // Run driveForward when F Up is pressed
  Controller.ButtonFUp.pressed(driveForward);
}

发布

released registers a function that runs when the button is released.

可用功能

void released(void (* callback)(void)) const;

范围	类型	描述
callback	void (*)(void)	按钮释放时运行的函数。

返回值

此函数不返回值。

例子

Define the callback function outside of main.

// Stop the drivetrain when F Up is released
void stopDriving() {
  Drivetrain.stop();
}

Register the callback inside main.

int main() {
  vexcodeInit();

  // Run stopDriving when F Up is released
  Controller.ButtonFUp.released(stopDriving);
}