日常开发收集，
-
页面刷新 uni.navigateBack() 无效
// 点击返回
cliNavBack() {
let canNavBack = getCurrentPages();
if(canNavBack && canNavBack.length>1) {
uni.navigateBack({delta: 1});
} else {
history.back();
}
return false
},-
canvas 签名区域组件
<template>
<view class="qinaming">
<canvas class="mycanvas" canvas-id="mycanvas"
@touchstart="touchstart" @touchmove="touchmove" @touchend="touchend"
:disable-scroll='true'
></canvas>
<view class="close" @click="clear">
<uni-icons type="loop"></uni-icons>
清空重签
</view>
</view>
</template>
<script>
var x = 20;
var y =20;
export default{
data(){
return {
ctx: '', //绘图图像
points: [], //路径点集合
isEnd: false, // 是否结束签名
image:'',
yuliu:''
}
},
created() {
this.ctx = uni.createCanvasContext("mycanvas",this); //创建绘图对象
//设置画笔样式
this.ctx.lineWidth = 4;
this.ctx.lineCap = "round"
this.ctx.lineJoin = "round"
this.ctx.fillStyle="#f4f4f4"
this.ctx.fillRect(0,0,300,300);
},
methods:{
//触摸开始，获取到起点
touchstart:function(e){
let startX = e.changedTouches[0].x;
let startY = e.changedTouches[0].y;
let startPoint = {X:startX,Y:startY};
this.points.push(startPoint);
//每次触摸开始，开启新的路径
this.ctx.beginPath();
},
//触摸移动，获取到路径点
touchmove:function(e){
let moveX = e.changedTouches[0].x;
let moveY = e.changedTouches[0].y;
let movePoint = {X:moveX,Y:moveY};
this.points.push(movePoint); //存点
let len = this.points.length;
if(len>=2){
this.draw(); //绘制路径
}
},
// 触摸结束，将未绘制的点清空防止对后续路径产生干扰
touchend:function(){
this.points=[];
this.isEnd = true
this.finish()
},
/* ***********************************************
# 绘制笔迹
# 1.为保证笔迹实时显示，必须在移动的同时绘制笔迹
# 2.为保证笔迹连续，每次从路径集合中区两个点作为起点（moveTo）和终点(lineTo)
# 3.将上一次的终点作为下一次绘制的起点（即清除第一个点）
************************************************ */
draw: function() {
let point1 = this.points[0]
let point2 = this.points[1]
this.points.shift()
this.ctx.moveTo(point1.X, point1.Y)
this.ctx.lineTo(point2.X, point2.Y)
this.ctx.stroke()
this.ctx.draw(true)
},
//清空画布
clear:function(){
let that = this;
uni.getSystemInfo({
success: function(res) {
let canvasw = res.windowWidth;
let canvash = res.windowHeight;
that.ctx.clearRect(0, 0, canvasw, canvash);
that.ctx.draw(true);
},
})
},
//完成绘画并保存到本地
finish:function(){
let that = this
if(!this.isEnd){
uni.showToast({
title: '请先完成签名',
icon: "none",
duration: 1500,
mask: true
})
return
}
uni.canvasToTempFilePath({
canvasId: 'mycanvas',
fileType:'png',
success: function(res) {
console.log(res);
that.yuliu=res.tempFilePath
that.debounce(that.fanhuiImg())
}
})
},
// 手写一个防抖函数来解决重复请求后台服务器的问题
debounce(fn) {
var timer = null;
let that=this
return function () {
if (timer) clearTimeout(timer)
timer = setTimeout(() => {
timer=null
fn.apply(this, arguments);
}, 1000)
}
},
fanhuiImg(){
this.$emit('signDone',this.yuliu)
},
// 生成图片
createImg:function(dataurl, filename = 'file'){
let arr = dataurl.split(',')
let mime = arr[0].match(/:(.*?);/)[1]
let suffix = mime.split('/')[1]
let bstr = atob(arr[1])
let n = bstr.length
let u8arr = new Uint8Array(n)
while (n--) {
u8arr[n] = bstr.charCodeAt(n)
}
return new File([u8arr], `${filename}.${suffix}`, {
type: mime
})
}
},
}
</script>
<style>
.qinaming{
height: 400rpx;
background-color: #f4f4f4;
}
.mycanvas{
height: 350rpx;
width: 100%;
}
.close{font-size: 22rpx;display: flex;justify-content: flex-end;align-items: center;margin-right: 30rpx;}
</style>-
html2canvas生成海报图片，将编写的样式截屏成图片
注意：网络图片本地生成后会空白 上线后图片正常显示
npm install --save html2canvas<template>
<view class="haibao">
<!-- 生成图片的标签展示 -->
<view id="capture" class="imgsc"></view>
<!-- 想要生成照片的区域 -->
<view id="shouxie" class="shouxie" v-if="!isSuccess">
<!-- 需要自己写出来 -->
</view>
</view>
</template>
<script>
import html2canvas from 'html2canvas';
export default {
data() {
return {
isSuccess:false
};
},
onLoad() {
this.getInit()
},
methods:{
shengChengNum(){
return Date.now ();
},
getInit(){
uni.showLoading({title:'生成中...'})
setTimeout(()=>{
this.cliShengCheng()
},2000)
},
cliShengCheng(){
html2canvas(document.querySelector('#shouxie'),{}).then(function(canvas) {
let oImg = new Image();
oImg.src = canvas.toDataURL();
const imgData = canvas.toDataURL('image/jpeg', 1.0);
document.querySelector('#capture').appendChild(canvas);
console.log(canvas,imgData);
}).then(()=>{
uni.hideLoading();
this.isSuccess=true;
this.downloadImg()
})
}
}
}
</script>
<style lang="scss" scoped>
</style>