setCanvas(){

let self = this;

//选取画板

const query = wx.createSelectorQuery()

query.select('#posterCanvas')

.fields({ node: true, size: true })

.exec(async (res) => {

const canvas = res[0].node;

//保存canvas实例

self.canvasObj = canvas;

const ctx = canvas.getContext('2d');

// canvas.width = res[0].width;

// canvas.height = res[0].height;

const dpr = wx.getSystemInfoSync().pixelRatio;

canvas.width = res[0].width * dpr;

canvas.height = res[0].height * dpr;

ctx.scale(dpr, dpr);

ctx.clearRect(0, 0, 320, 410); //清空画板

ctx.fillStyle = '#fff';

ctx.fillRect(0, 0, 320, 410);

let txtLeftPos = 65;

ctx.textBaseline = "top";

ctx.textAlign = 'left';

ctx.font = "30px bold"; //设置字体大小，默认10

ctx.fillStyle = '#000'; //文字颜色：默认黑色

ctx.fillText("一键闪退", txtLeftPos, 295)//绘制文本

});

},

之后，我就报错。

搞不懂，更新个毛线，浪费我一天时间。你要更新要么给出案例来。不知道你更新后就留下介绍，是几个意思啊。