WeChat mini-app gesture operation: single touch point and multi-touch point, mini-app gesture

Source: Internet
Author: User

Small Program gesture operation: single touch point and multi-touch point, small program gesture

Preface

Gestures are important for some effects. They are widely used in canvas and interaction. Let's take a look at the small program gestures.

Demo

To check whether the applet supports multiple fingers, you need to use touchstart, touchmove, and touchend.

// index.wxml<view id="gestureView" bindtouchstart="touchstartFn" bindtouchmove="touchmoveFn" bindtouchend="touchendFn" ></view>
//index.jstouchstartFn: function(event){  console.log(event); }, touchmoveFn: function(event){  console.log(event);  // console.log("move: PageX:"+ event.changedTouches[0].pageX); }, touchendFn: function(event){  console.log(event);  // console.log("move: PageX:"+ event.changedTouches[0].pageX); }

Single-touch and multi-touch

Official Document: changedTouches

The data format of changedTouches is the same as that of touches. Indicates the changed touch points, such as touchstart, touchmove, and touchcancel ).

"changedTouches":[{ "identifier":0, "pageX":53, "pageY":14, "clientX":53, "clientY":14}]

Real machine Effect

After the above Demo is implemented, the simulator cannot see the data of multiple touch points, so you need a real machine to test.

Check the log information of the real machine.

In changedTouches, the touch point data is stored sequentially, so the applet itself supports multi-touch gestures.

Conclusion

Imagine: Since the gesture of a applet supports multi-touch and relevant paths can be obtained, it is also feasible to calculate the related paths.

Scenario: multi-touch interaction, finger drawing, etc.

Save touch point data

In order to be able to analyze the path of a touch point, at least simple gestures, such as left, right, up, and down, we need to save all the data of the path.

Touch event

Touch-triggered events include "touchstart", "touchmove", "touchend", and "touchcancel ".

See: https://mp.weixin.qq.com/debug/wxadoc/dev/framework/view/wxml/event.html20

Store Data

Var _ wxChanges = []; var _ wxGestureDone = false; const _ wxGestureStatus = ["touchstart", "touchmove", "touchend", "touchcancel"]; // collection path function g (e) {if (e. type = "touchstart") {_ wxChanges = []; _ wxGestureDone = false;} if (! _ WxGestureDone) {_ wxChanges. push (e); if (e. type = "touchend") {_ wxGestureDone = true;} else if (e. type = "touchcancel") {_ wxChanges = []; _ wxGestureDone = true ;}}}

End

This article mainly explores how to parse gestures in advance.

Related Article

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

  • Sales Support

    1 on 1 presale consultation

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.