手勢解鎖是app上常見的解鎖方式，相比輸入密碼方式操作起來要方便許多。下面展示如何基于微信小程序實現手機解鎖。最終實現效果如下圖:
整個功能基于canvas實現，首先添加畫布組件，并設定樣式
<!--index.wxml--><view class="container"> <canvas canvas-id="id-gesture-lock" class="gesture-lock" bindtouchstart="onTouchStart" bindtouchmove="onTouchMove" bindtouchend="onTouchEnd"></canvas></view>
.gesture-lock { margin: 100rpx auto; width: 300px; height: 300px; background-color: #ffffff;}手勢解鎖實現代碼在gesture_lock.js中(完整源碼地址見末尾)。
初始化
constructor(canvasid, context, cb, opt){ this.touchPoints = []; this.checkPoints = []; this.canvasid = canvasid; this.ctx = context; this.width = opt && opt.width || 300; //畫布長度 this.height = opt && opt.height || 300; //畫布寬度 this.cycleNum = opt && opt.cycleNum || 3; this.radius = 0; //觸摸點半徑 this.isParamOk = false; this.marge = this.margeCircle = 25; //觸摸點及觸摸點和畫布邊界間隔 this.initColor = opt && opt.initColor || '#C5C5C3'; this.checkColor = opt && opt.checkColor || '#5AA9EC'; this.errorColor = opt && opt.errorColor || '#e19984'; this.touchState = "unTouch"; this.checkParam(); this.lastCheckPoint = null; if (this.isParamOk) { // 計算觸摸點的半徑長度 this.radius = (this.width - this.marge * 2 - (this.margeCircle * (this.cycleNum - 1))) / (this.cycleNum * 2) this.radius = Math.floor(this.radius); // 計算每個觸摸點的圓心位置 this.calCircleParams(); } this.onEnd = cb; //滑動手勢結束時的回調函數 }主要設置一些參數，如canvas的長寬，canvas的context，手勢鎖的個數(3乘3, 4乘4)，手勢鎖的顏色，手勢滑動結束時的回調函數等。并計算出手勢鎖的半徑。
計算每個手勢鎖的圓心位置
calCircleParams() { let n = this.cycleNum; let count = 0; for (let i = 0; i < n; i++) { for (let j = 0; j < n; j++){ count++; let touchPoint = { x: this.marge + i * (this.radius * 2 + this.margeCircle) + this.radius, y: this.marge + j * (this.radius * 2 + this.margeCircle) + this.radius, index: count, check: "uncheck", } this.touchPoints.push(touchPoint) } } }繪制手勢鎖
for (let i = 0; i < this.touchPoints.length; i++){ this.drawCircle(this.touchPoints[i].x, this.touchPoints[i].y, this.radius, this.initColor) } this.ctx.draw(true);接下來就是識別用戶的滑動行為，判斷用戶劃過了哪些圓圈，進而識別出用戶的手勢。
在touchstart和touchmove事件中檢測觸發并更新畫布
onTouchStart(e) { // 不識別多點觸控 if (e.touches.length > 1){ this.touchState = "unTouch"; return; } this.touchState = "startTouch"; this.checkTouch(e); let point = {x:e.touches[0].x, y:e.touches[0].y}; this.drawCanvas(this.checkColor, point); } onTouchMove(e) { if (e.touchState === "unTouch") { return; } if (e.touches.length > 1){ this.touchState = "unTouch"; return; } this.checkTouch(e); let point = {x:e.touches[0].x, y:e.touches[0].y}; this.drawCanvas(this.checkColor, point); }檢測用戶是否劃過某個圓圈
checkTouch(e) { for (let i = 0; i < this.touchPoints.length; i++){ let point = this.touchPoints[i]; if (isPointInCycle(e.touches[0].x, e.touches[0].y, point.x, point.y, this.radius)) { if (point.check === 'uncheck') { this.checkPoints.push(point); this.lastCheckPoint = point; } point.check = "check" return; } } }更新畫布
drawCanvas(color, point) { //每次更新之前先清空畫布 this.ctx.clearRect(0, 0, this.width, this.height); //使用不同顏色和形式繪制已觸發和未觸發的鎖 for (let i = 0; i < this.touchPoints.length; i++){ let point = this.touchPoints[i]; if (point.check === "check") { this.drawCircle(point.x, point.y, this.radius, color); this.drawCircleCentre(point.x, point.y, color); } else { this.drawCircle(this.touchPoints[i].x, this.touchPoints[i].y, this.radius, this.initColor) } } //繪制已識別鎖之間的線段 if (this.checkPoints.length > 1) { let lastPoint = this.checkPoints[0]; for (let i = 1; i < this.checkPoints.length; i++) { this.drawLine(lastPoint, this.checkPoints[i], color); lastPoint = this.checkPoints[i]; } } //繪制最后一個識別鎖和當前觸摸點之間的線段 if (this.lastCheckPoint && point) { this.drawLine(this.lastCheckPoint, point, color); } this.ctx.draw(true); }當用戶滑動結束時調用回調函數并傳遞識別出的手勢
onTouchEnd(e) { typeof this.onEnd === 'function' && this.onEnd(this.checkPoints, false); } onTouchCancel(e) { typeof this.onEnd === 'function' && this.onEnd(this.checkPoints, true); }重置和顯示手勢錯誤
gestureError() { this.drawCanvas(this.errorColor) } reset() { for (let i = 0; i < this.touchPoints.length; i++) { this.touchPoints[i].check = 'uncheck'; } this.checkPoints = []; this.lastCheckPoint = null; this.drawCanvas(this.initColor); }如何調用
在onload方法中創建lock對象并在用戶觸摸事件中調用相應方法
onLoad: function () { var s = this; this.lock = new Lock("id-gesture-lock", wx.createCanvasContext("id-gesture-lock"), function(checkPoints, isCancel) { console.log('over'); s.lock.gestureError(); setTimeout(function() { s.lock.reset(); }, 1000); }, {width:300, height:300}) this.lock.drawGestureLock(); console.log('onLoad') var that = this //調用應用實例的方法獲取全局數據 app.getUserInfo(function(userInfo){ //更新數據 that.setData({ userInfo:userInfo }) that.update() }) }, onTouchStart: function (e) { this.lock.onTouchStart(e); }, onTouchMove: function (e) { this.lock.onTouchMove(e); }, onTouchEnd: function (e) { this.lock.onTouchEnd(e); }源碼地址:源碼下載
以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持武林網。
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