有 Home.vue
和 Statistics.vue
页面。 Home.vue
渲染 TableFields.vue
组件。在 Home.vue
中,有一些字段编号,在页面加载时设置了初始值“3”。设置计算函数的间隔每两秒添加一次数字。如何实现从“/”到“/statistics”时所有更改都应暂停,而返回时应恢复?在主页的每个字段下方,已经有一些按钮可以切换 setInterval() 函数和停止/恢复计算。基本上,当从“/”到“/statistics”时,应该触发 clearInterval()
来停止“/”页面的计算。 @Saksham TableFields.vue:
<template>
<div>
<table class="table-a">
<tr>
<th>A</th>
<td class="sign">{{ this.randomSign.A }}</td>
<td>{{ initialValue.A }}</td>
<td v-show="this.randomSign.A == '+'">⬆</td>
<td v-show="this.randomSign.A == '-'">⬇</td>
</tr>
</table>
<button @click="toggleIntervalA()">
<span v-show="this.startStop.A">Stop</span>
<span v-show="!this.startStop.A">Start</span>
</button>
<table class="table-b">
<tr>
<th>B</th>
<td class="sign">{{ this.randomSign.B }}</td>
<td>{{ initialValue.B }}</td>
<td v-show="this.randomSign.B == '+'">⬆</td>
<td v-show="this.randomSign.B == '-'">⬇</td>
</tr>
</table>
<button @click="toggleIntervalB()">
<span v-show="this.startStop.B">Stop</span>
<span v-show="!this.startStop.B">Start</span>
</button>
</div>
</template>
<script>
export default {
name: 'TableFields',
props: {
changesA: {
type: Array,
required: false
},
changesB: {
type: Array,
required: false
}
},
data () {
return {
fields: ['A', 'B'],
startStop: {
A: true,
B: true
},
initialValue: {
A: 3,
B: 3
},
randomNumbersArray: [],
randomSign: {
A: '+',
B: '+'
},
signsArray: ['+', '-'],
interval: {
A: null,
B: null
},
localChanges: {
A: [],
B: []
},
timer: undefined
}
},
computed: {},
methods: {
firstObjects () {
for (let i = 0; i < this.fields.length; i++) {
const date = new Date()
const obj = {}
obj.field = this.fields[i]
obj.value = Number((Math.random() * 1 + 1).toFixed(2))
obj.time = date.toLocaleTimeString()
this.changesA.push(obj[0])
this.changesB.push(obj[1])
this.$emit('update:changesA', this.localChanges.A)
this.$emit('update:changesB', this.localChanges.B)
}
},
replaceNumbersArray () { // replace random A, B numbers at time interval
const n1 = Number((Math.random() * 1 + 1).toFixed(2)) // n1 = first number (A)
const n2 = Number((Math.random() * 1 + 1).toFixed(2)) // n2 = second number (B)
this.randomNumbersArray.splice(0, 2, n1, n2)
},
toggleIntervalA () {
this.startStop.A = !this.startStop.A
if (this.startStop.A) {
this.interval.A = setInterval(this.calculationsA, 2000)
} else {
clearInterval(this.interval.A)
}
},
toggleIntervalB () {
this.startStop.B = !this.startStop.B
if (this.startStop.B) {
this.interval.B = setInterval(this.calculationsB, 2000)
} else {
clearInterval(this.interval.B)
}
},
calculationsA () {
this.randomSign.A = this.signsArray[
Math.floor(Math.random() * this.signsArray.length)
]
this.randomSign.A === '+'
? (this.initialValue.A += this.randomNumbersArray[0])
: (this.initialValue.A -= this.randomNumbersArray[0])
const date = new Date()
const newChange = {}
newChange.field = 'A'
newChange.value = this.randomNumbersArray[0]
newChange.time = date.toLocaleTimeString()
this.changesA.push(newChange)
this.$emit('update:changesA', this.localChanges.A)
},
calculationsB () {
this.randomSign.B = this.signsArray[
Math.floor(Math.random() * this.signsArray.length)
]
this.randomSign.B === '+'
? (this.initialValue.B += this.randomNumbersArray[1])
: (this.initialValue.B -= this.randomNumbersArray[1])
const date = new Date()
const newChange = {}
newChange.field = 'B'
newChange.value = this.randomNumbersArray[1]
newChange.time = date.toLocaleTimeString()
this.changesB.push(newChange)
this.$emit('update:changesB', this.localChanges.B)
}
},
mounted () {
this.firstObjects()
setInterval(this.replaceNumbersArray, 2000)
this.initialValue.A = this.$root.initialValue.A || 3
this.initialValue.B = this.$root.initialValue.B || 3
this.timer = setInterval(_ => {
this.interval.A = this.calculationsA
this.interval.B = this.calculationsB
}, 2000)
},
beforeDestroy () {
clearInterval(this.timer)
this.$root.initialValue.A = this.initialValue.A
this.$root.initialValue.B = this.initialValue.B
}
}
</script>
<style lang="scss" scoped>
.table-b {
margin-top: 15px;
}
.sign {
width: 12px;
text-align: center;
}
button {
border: 1px solid transparent;
border-radius: 0;
background-color: #42b983;
color: #ffffff;
margin-top: 7px;
padding: 5px 10px;
&:hover {
opacity: 0.9;
cursor: pointer;
}
}
</style>
项目仓库:link
最佳答案
尝试使用 beforeDestroy()
钩子(Hook)将计数器推送到根组件或 vuex 存储(如果您使用的话),并在 mounted()< 中获取计数器
钩子(Hook)一旦你返回到从那里恢复的路线。
并在您的组件中使用为
export default {
...
beforeDestroy () {
this.$root.counter = this.counter;
},
mounted () {
this.counter = this.$root.counter || 0;
}
...
}
我在 https://codesandbox.io/s/preserve-timer-state-2osi7 创建了一个沙箱当我们离开路线时,它会保留计时器的状态,并从我们离开的地方启动计时器。
评论说明:
根据您的评论,您似乎正在尝试为 undefined object 设置属性。最初,根组件中没有名为 initialValue
的属性,并且您尝试访问其中的属性 A
。
您需要首先检查 initialValue
是否已定义,然后尝试检查 A
this.initialValue.A = this.$root.initialValue && this.$root.initialValue.A ? this.$root.initialValue.A : 3
还要确保您的数据将 initialValue
作为空对象
initialValue: {}
关于javascript - 页面历史记录的暂停功能 向前 向后,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/61243150/