Javascript Pomodoro时钟(使用React挂钩)倒计时未开始
尝试重构此文件以使用React挂钩。单击“开始计时器”按钮时,遇到倒计时未开始的问题。我认为问题来自intervalRef 我是否正确使用useRef 如果你不想去沙箱:Javascript Pomodoro时钟(使用React挂钩)倒计时未开始,javascript,reactjs,react-hooks,Javascript,Reactjs,React Hooks,尝试重构此文件以使用React挂钩。单击“开始计时器”按钮时,遇到倒计时未开始的问题。我认为问题来自intervalRef 我是否正确使用useRef 如果你不想去沙箱: import React, {useState, useRef } from 'react' export default function Pomodoro() { const [seconds, setSeconds] = useState(0) const [workMinutes, setWorkM
import React, {useState, useRef } from 'react'
export default function Pomodoro() {
const [seconds, setSeconds] = useState(0)
const [workMinutes, setWorkMinutes] = useState(25)
const [restMinutes, setRestMinutes] = useState(5)
const [start, setStart] = useState(false)
const [relax, setRelax] = useState(false)
// Control functions
const intervalRef = useRef();
function startTimer() {
if(!intervalRef.current){
intervalRef.current = setInterval(1000)
}
setStart(!start)
}
function pauseTimer() {
if(!intervalRef.current){
clearInterval(intervalRef.current)
intervalRef.current = undefined
}
}
function resetTimer() {
if(!intervalRef.current){
clearInterval(intervalRef.current)
intervalRef.current = undefined
}
setSeconds(0)
setWorkMinutes(25)
setRestMinutes(5)
setStart(false)
setRelax(false)
}
function timer() {
if(seconds === 0){
setSeconds(59)
}else{
setSeconds(seconds - 1)
}
if(relax) {
if(seconds === 0){
setRestMinutes(restMinutes - 1)
}
else if(restMinutes === 5){
setRestMinutes(4)
}else{
setRestMinutes(restMinutes)
}
}
if(restMinutes === -1) {
setRestMinutes(5)
setRelax(false)
} else {
setWorkMinutes( seconds === 0 ? workMinutes - 1 : workMinutes === 25 ? 24 : workMinutes)
if (workMinutes === -1) {
setWorkMinutes(25)
setRelax(true)
}
}
}
return (
<>
{timer}
<p>{relax ? 'Take a Break' : 'Get Busy'}</p>
<p>{relax ? restMinutes : workMinutes} : {seconds < 10 ? `0${seconds}` : seconds}</p>
<button onClick={start ? pauseTimer: startTimer}>{start ? 'Pause' : 'Start'}</button>
<button onClick={resetTimer}>Reset</button>
</>
)
}
import React,{useState,useRef}来自“React”
导出默认函数pomotoro(){
常量[秒,设置秒]=使用状态(0)
const[workMinutes,setWorkMinutes]=useState(25)
const[restMinutes,setRestMinutes]=useState(5)
const[start,setStart]=useState(false)
const[relax,setRelax]=useState(false)
//控制功能
const intervalRef=useRef();
函数startTimer(){
如果(!intervalRef.current){
intervalRef.current=设置间隔(1000)
}
设置开始(!开始)
}
函数pauseTimer(){
如果(!intervalRef.current){
清除间隔(间隔参考电流)
intervalRef.current=未定义
}
}
函数resetTimer(){
如果(!intervalRef.current){
清除间隔(间隔参考电流)
intervalRef.current=未定义
}
设置秒(0)
设置工作分钟数(25)
setRestMinutes(5)
设置开始(错误)
setRelax(假)
}
函数计时器(){
如果(秒===0){
设置秒(59)
}否则{
设置秒(秒-1)
}
如果(放松){
如果(秒===0){
setRestMinutes(restMinutes-1)
}
else if(restMinutes==5){
setRestMinutes(4)
}否则{
setRestMinutes(restMinutes)
}
}
如果(restMinutes==-1){
setRestMinutes(5)
setRelax(假)
}否则{
setWorkMinutes(秒===0?工作分钟-1:工作分钟===25?24:工作分钟)
如果(工作分钟==-1){
设置工作分钟数(25)
setRelax(真)
}
}
}
返回(
{计时器}
{放松?'休息一下':'忙碌起来'}
{relax?restMinutes:workMinutes}:{seconds<10?`0${seconds}`:seconds}
{开始?'Pause':'start'}
重置
)
}
您忘记了在setInterval
中回调,但我还是希望这样做:
import React, { useState, useEffect } from "react";
export default function Pomodoro() {
const [seconds, setSeconds] = useState(25 * 60);
const [paused, setPaused] = useState(true);
useEffect(() => {
const int = setInterval(() => {
console.log(`${Date.now()} - paused: ${paused}`);
if (!paused) {
setSeconds(s => s - 1);
}
}, 1000);
return () => {
clearInterval(int);
};
}, [paused]);
function startTimer() {
setPaused(false);
}
function pauseTimer() {
setPaused(true);
}
function resetTimer() {
setPaused(true);
setSeconds(25 * 60);
}
return (
<>
{`${Math.floor(seconds / 60)}:${("00" + (seconds % 60)).slice(-2)}`}
<button onClick={paused ? startTimer : pauseTimer}>
{paused ? "Start" : "Pause"}
</button>
<button onClick={resetTimer}>Reset</button>
</>
);
}
或者在另一个状态下处理它,但是你需要做两次每件事(只有当你在切换时关心记住旧的状态时才可以)
您忘记了在
setInterval
中回调,但我还是希望这样做:
import React, { useState, useEffect } from "react";
export default function Pomodoro() {
const [seconds, setSeconds] = useState(25 * 60);
const [paused, setPaused] = useState(true);
useEffect(() => {
const int = setInterval(() => {
console.log(`${Date.now()} - paused: ${paused}`);
if (!paused) {
setSeconds(s => s - 1);
}
}, 1000);
return () => {
clearInterval(int);
};
}, [paused]);
function startTimer() {
setPaused(false);
}
function pauseTimer() {
setPaused(true);
}
function resetTimer() {
setPaused(true);
setSeconds(25 * 60);
}
return (
<>
{`${Math.floor(seconds / 60)}:${("00" + (seconds % 60)).slice(-2)}`}
<button onClick={paused ? startTimer : pauseTimer}>
{paused ? "Start" : "Pause"}
</button>
<button onClick={resetTimer}>Reset</button>
</>
);
}
或者在另一个状态下处理它,但是你需要做两次每件事(只有当你在切换时关心记住旧的状态时才可以)
const [relax, setRelax] = useState(false);
const [relaxSeconds, setRelaxSeconds] = useState(10 * 60);
useEffect(() => {
const int = setInterval(() => {
console.log(`${Date.now()} - paused: ${paused}`);
if (!paused) {
relax ? setRelaxSecdonds(s => s - 1) : setSeconds(s => s - 1);
}
}, 1000);
return () => {
clearInterval(int);
};
}, [paused, relax]);