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
`ButtonA`	`Controller.ButtonA.pressing()`	A 键。
`ButtonB`	`Controller.ButtonB.pressing()`	B 键。
`ButtonDown`	`Controller.ButtonDown.pressing()`	向下按钮。
`ButtonUp`	`Controller.ButtonUp.pressing()`	向上按钮。
`ButtonL1`	`Controller.ButtonL1.pressing()`	L1 按钮。
`ButtonL2`	`Controller.ButtonL2.pressing()`	L2 按钮。
`ButtonL3`	`Controller.ButtonL3.pressing()`	L3 按钮。
`ButtonR1`	`Controller.ButtonR1.pressing()`	R1按钮。
`ButtonR2`	`Controller.ButtonR2.pressing()`	R2 按钮。
`ButtonR3`	`Controller.ButtonR3.pressing()`	R3按钮。

笔记 #

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

// 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 #

pressing #

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 L1 is pressed
while (true) {
  if (Controller.ButtonL1.pressing()) {
    Drivetrain.turn(right);
  }
  else {
    Drivetrain.stop();
  }

  wait(20, msec);
}

回调函数 #

pressed #

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 R1 is pressed
void driveForward() {
  Drivetrain.driveFor(forward, 200, mm);
}

int main() {
  vexcodeInit();

  // Run driveForward when R1 is pressed
  Controller.ButtonR1.pressed(driveForward);
}

released #

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 R1 is released
void stopDriving() {
  Drivetrain.stop();
}

int main() {
  vexcodeInit();

  // Run stopDriving when R1 is released
  Controller.ButtonR1.released(stopDriving);
}