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
<!--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.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);
}
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) {
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);
}
以上就是微信小程序开发手势解锁实例代码的详细内容。