微信小程序开发教程

微信小程序开发教程

手势解锁是app上常见的解锁方式，相比输入密码方式操作起来要方便许多。下面展示如何基于微信小程序实现手机解锁。最终实现效果如下图:

整个功能基于canvas实现，首先添加画布组件，并设定样式

bindtouchmove="onTouchMove" bindtouchend="onTouchEnd">

bindtouchmove="onTouchMove" bindtouchend="onTouchEnd">

.gesture-lock {

margin: 100rpx auto;

width: 300px;

height: 300px;

background-color: #ffffff;

}

手势解锁实现代码在gesture_lock.js中(完整源码地址见末尾)。

初始化

constructor(canvasid, context, cb, opt){

this.touchPoints = [];

this.checkPoints = [];

this.canvasid = canvasid;

this.ctx = context;

this.width = opt && opt.width || 300; //画布长度

this.height = opt && opt.height || 300; //画布宽度

this.cycleNum = opt && opt.cycleNum || 3;

this.radius = 0; //触摸点半径

this.isParamOk = false;

this.marge = this.margeCircle = 25; //触摸点及触摸点和画布边界间隔

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) {

// 计算触摸点的半径长度

this.radius = (this.width - this.marge * 2 - (this.margeCircle * (this.cycleNum - 1))) / (this.cycleNum * 2)

this.radius = Math.floor(this.radius);

// 计算每个触摸点的圆心位置

this.calCircleParams();

}

this.onEnd = cb; //滑动手势结束时的回调函数

}

主要设置一些参数，如canvas的长宽，canvas的context，手势锁的个数(3乘3, 4乘4)，手势锁的颜色，手势滑动结束时的回调函数等。并计算出手势锁的半径。

计算每个手势锁的圆心位置

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)

}

}

}

绘制手势锁

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);

接下来就是识别用户的滑动行为，判断用户划过了哪些圆圈，进而识别出用户的手势。

在touchstart和touchmove事件中检测触发并更新画布

onTouchStart(e) {

// 不识别多点触控

if (e.touches.length > 1){

this.touchState = "unTouch";

return;

}

this.touchState = "startTouch";

this.checkTouch(e);

let point = {x:e.touchhttp://es[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);

}

检测用户是否划过某个圆圈

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;

}

}

}

更新画布

drawCanvas(color, point) {

//每次更新之前先清空画布

this.ctx.clearRect(0, 0, this.width, this.height);

//使用不同颜色和形式绘制已触发和未触发的锁

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)

}

}

//绘制已识别锁之间的线段

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];

}

}

//绘制最后一个识别锁和当前触摸点之间的线段

if (this.lastCheckPoint && point) {

tUHRd this.drawLine(this.lastCheckPoint, point, color);

}

this.ctx.draw(true);

}

当用户滑动结束时调用回调函数并传递识别出的手势

onTouchEnd(e) {

typeof this.onEnd === 'function' && this.onEnd(this.checkPoints, false);

}

onTouchCancel(e) {

typeof this.onEnd === 'function' && this.onEnd(this.checkPoints, true);

}

重置和显示手势错误

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);

}

如何调用

在onload方法中创建lock对象并在用户触摸事件中调用相应方法

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

//调用应用实例的方法获取全局数据

app.getUserInfo(function(userInfo){

//更新数据

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);

}

源码地址:源码下载

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