- Growing up’s a funny thing. Sneaks up on you.
長大是件很有趣的事，不經意間就發生了。
一、概括
-
項目的倉庫地址：https://github.com/0x1abin/MultiButton
0x1abin大佬的超精簡的軟件定時器multi_timer已經讓人眼前一亮，如今這個按鍵組件MultiButton更令我折服。把按鍵的各種事件（按下觸發、按下彈出觸發、單擊、雙擊、長按等）用狀態機非常perfect的實現了。該組件兼具按鍵的消抖處理，親測效果非常不錯。同時，該組件非常易於添加到項目的代碼裏，只需要簡單的幾步操作。
說着說着，膝蓋又疼了。
二、使用和代碼分析
發現兩篇文章把這個組件的使用和代碼分析都講得蠻清楚了，沒興趣看github上的源碼，可以有興趣看一下下面的文章：
三、項目源代碼和個人的註釋
multi_button.h
/*
* Copyright (c) 2016 Zibin Zheng <[email protected]>
* All rights reserved
*/
#ifndef _MULTI_BUTTON_H_
#define _MULTI_BUTTON_H_
#include "stdint.h"
#include "string.h"
//According to your need to modify the constants.
#define TICKS_INTERVAL 5 //ms
#define DEBOUNCE_TICKS 3 //MAX 8
#define SHORT_TICKS (300 /TICKS_INTERVAL)
#define LONG_TICKS (1000 /TICKS_INTERVAL)
typedef void (*BtnCallback)(void*);
typedef enum {
PRESS_DOWN = 0, // 按鍵按下，每次按下都觸發
PRESS_UP, // 按鍵彈起，每次鬆開都觸發
PRESS_REPEAT, // 重複按下觸發，變量repeat計數連擊次數
SINGLE_CLICK, // 單擊按鍵事件
DOUBLE_CLICK, // 雙擊按鍵事件
LONG_RRESS_START, // 達到長按時間閾值時觸發一次
LONG_PRESS_HOLD, // 長按期間一直觸發
number_of_event, // 事件種類數
NONE_PRESS
}PressEvent;
typedef struct Button {
uint16_t ticks;
uint8_t repeat : 4; // 記錄連擊次數
uint8_t event : 4; // 記錄具體事件
uint8_t state : 3; // 下一個要跳轉的狀態，用於狀態的切換
uint8_t debounce_cnt : 3; // 記錄持續次數（每次固定時間，用於去抖）
uint8_t active_level : 1; // 有效電平（按鍵按下時的電平）
uint8_t button_level : 1; // 記錄當前的電平
uint8_t (*hal_button_Level)(void); // 函數指針（指向獲取當前按鍵電平的函數）
BtnCallback cb[number_of_event]; // 函數指針數組：分別指向各個事件的回調函數
struct Button* next;
}Button;
#ifdef __cplusplus
extern "C" {
#endif
void button_init(struct Button* handle, uint8_t(*pin_level)(), uint8_t active_level);
void button_attach(struct Button* handle, PressEvent event, BtnCallback cb);
PressEvent get_button_event(struct Button* handle);
int button_start(struct Button* handle);
void button_stop(struct Button* handle);
void button_ticks(void);
#ifdef __cplusplus
}
#endif
#endif
multi_button.c
/*
* Copyright (c) 2016 Zibin Zheng <[email protected]>
* All rights reserved
*/
#include "multi_button.h"
#define EVENT_CB(ev) if(handle->cb[ev]) handle->cb[ev]((Button*)handle) // 執行回調函數
//button handle list head.
static struct Button* head_handle = NULL;
/**
* @brief Initializes the button struct handle.
* @param handle: the button handle strcut.
* @param pin_level: read the HAL GPIO of the connet button level.
* @param active_level: pressed GPIO level.
* @retval None
*/
void button_init(struct Button* handle, uint8_t(*pin_level)(), uint8_t active_level)
{
memset(handle, 0, sizeof(struct Button));
handle->event = (uint8_t)NONE_PRESS;
handle->hal_button_Level = pin_level;
handle->button_level = handle->hal_button_Level(); // 得到當前電平
handle->active_level = active_level;
}
/**
* @brief Attach the button event callback function.
* @param handle: the button handle strcut.
* @param event: trigger event type.
* @param cb: callback function.
* @retval None
*/
void button_attach(struct Button* handle, PressEvent event, BtnCallback cb)
{
handle->cb[event] = cb; // 將事件類型與回調函數綁定
}
/**
* @brief Inquire the button event happen.
* @param handle: the button handle strcut.
* @retval button event.
*/
// 返回按鍵事件類型
PressEvent get_button_event(struct Button* handle)
{
return (PressEvent)(handle->event);
}
/**
* @brief Button driver core function, driver state machine.
* @param handle: the button handle strcut.
* @retval None
*/
void button_handler(struct Button* handle)
{
uint8_t read_gpio_level = handle->hal_button_Level();
//ticks counter working..
if((handle->state) > 0) handle->ticks++;
/*------------button debounce handle---------------*/
if(read_gpio_level != handle->button_level) { //not equal to prev one
//continue read 3 times same new level change
if(++(handle->debounce_cnt) >= DEBOUNCE_TICKS) {
handle->button_level = read_gpio_level;
handle->debounce_cnt = 0;
}
} else { //leved not change ,counter reset.
handle->debounce_cnt = 0;
}
/*-----------------State machine-------------------*/
switch (handle->state) {
case 0:
if(handle->button_level == handle->active_level) { //start press down
handle->event = (uint8_t)PRESS_DOWN;
EVENT_CB(PRESS_DOWN); // 跳轉到回調函數
handle->ticks = 0;
handle->repeat = 1;
handle->state = 1;
} else {
handle->event = (uint8_t)NONE_PRESS;
}
break;
case 1:
if(handle->button_level != handle->active_level) { //released press up
handle->event = (uint8_t)PRESS_UP;
EVENT_CB(PRESS_UP); // 跳轉到回調函數
handle->ticks = 0;
handle->state = 2;
} else if(handle->ticks > LONG_TICKS) {
handle->event = (uint8_t)LONG_RRESS_START;
EVENT_CB(LONG_RRESS_START); // 長按
handle->state = 5;
}
break;
case 2:
if(handle->button_level == handle->active_level) { //press down again
handle->event = (uint8_t)PRESS_DOWN;
EVENT_CB(PRESS_DOWN);
handle->repeat++;
// 若將所有的按鍵事件回調函數寫在同一個函數裏，需要添加這一句（該回調函數內是靠handle->event來判斷怎麼處理）
// 除非你不需要處理PRESS_REPEAT
handle->event = (uint8_t)PRESS_REPEAT;
EVENT_CB(PRESS_REPEAT); // repeat hit
handle->ticks = 0;
handle->state = 3;
} else if(handle->ticks > SHORT_TICKS) { //released timeout
if(handle->repeat == 1) {
handle->event = (uint8_t)SINGLE_CLICK;
EVENT_CB(SINGLE_CLICK);
} else if(handle->repeat == 2) {
handle->event = (uint8_t)DOUBLE_CLICK;
EVENT_CB(DOUBLE_CLICK); // repeat hit
}
handle->state = 0;
}
break;
case 3:
if(handle->button_level != handle->active_level) { //released press up
handle->event = (uint8_t)PRESS_UP;
EVENT_CB(PRESS_UP);
if(handle->ticks < SHORT_TICKS) {
handle->ticks = 0;
handle->state = 2; //repeat press
} else {
handle->state = 0;
}
}
break;
case 5:
if(handle->button_level == handle->active_level) {
//continue hold trigger
handle->event = (uint8_t)LONG_PRESS_HOLD;
EVENT_CB(LONG_PRESS_HOLD);
} else { //releasd
handle->event = (uint8_t)PRESS_UP;
EVENT_CB(PRESS_UP);
handle->state = 0; //reset
}
break;
}
}
/**
* @brief Start the button work, add the handle into work list.
* @param handle: target handle strcut.
* @retval 0: succeed. -1: already exist.
*/
// 將按鍵結構體插入掃描隊列
int button_start(struct Button* handle)
{
struct Button* target = head_handle;
while(target) {
if(target == handle) return -1; //already exist.
target = target->next;
}
handle->next = head_handle;
head_handle = handle;
return 0;
}
/**
* @brief Stop the button work, remove the handle off work list.
* @param handle: target handle strcut.
* @retval None
*/
// 將按鍵結構體脫離掃描隊列
void button_stop(struct Button* handle)
{
struct Button** curr;
for(curr = &head_handle; *curr; ) {
struct Button* entry = *curr;
if (entry == handle) {
*curr = entry->next;
// free(entry);
} else
curr = &entry->next;
}
}
/**
* @brief background ticks, timer repeat invoking interval 5ms.
* @param None.
* @retval None
*/
// 將其放在週期定時執行的函數裏，每一個週期掃描一次各個按鍵是否有事件發生
void button_ticks()
{
struct Button* target;
for(target=head_handle; target; target=target->next) {
button_handler(target);
}
}