微信小程序--树莓派（raspberry pi）小车控制的代码流程

目录

1. 基本思路

2. 代码结构如下：

3. index目录

4. control目录 

5. 工程全局控制

主要练习了一下微信小程序的开发。这里简单记录一下主要代码片段。也是趟过了许多的坑，例如：微信小程序不支持完全全屏，微信小程序不能横屏展示。所以开发过程中也用了一些非常手段。可以说这只是一个很基本的demo，所以里面很多东西，比如摄像头监控ip、页面元素定位我都使用了写死的值。特别是界面，我只是在iPhone 6上面做的实验，所以换到其他手机上时，界面就会变型了。

1. 基本思路

• 进入小程序时展示index页，可以让用户输入服务端url（模拟上一篇中在浏览器获取get请求）

• 然后跳转到实际的小车控制界面，并可以通过点击按钮实现小车控制

• 控制小车的移动，主要是在control.js中定义了界面按钮事件的响应，在响应事件的过程中实现http请求的发送

index页面如下： 

进去之后的页面如下（其中中间空白处会展示摄像头监控，不过我并没有启动，所以看不见）：

2. 代码结构如下：

其中，index下面是首页，control是控制页面，res目录下存放的是图片资源

3. index目录

• index.js

//index.js
//获取应用实例
const app = getApp()

Page({
  data: {
    logo: "/res/rasp-logo.png",
    welcome: "欢迎使用树莓小车",
    enterBtn: "进入",
    PromoteMsg: "Please enter the server address (eg: http://x.x.x.x:8080)",
    reqURL: ""
  },
  // 从输入框中获取用户输入的服务器地址信息
  getURL: function (e) {
    this.setData({
      reqURL: e.detail.value
    })
  },
  enterClicked: function (e) {
    /*
     * 当按下进入按钮，需要做以下事情：
     * 1. 首先判断用户是否已经在输入框中输入完整的服务器地址
     * 2. 发起一个到服务器的GET请求，并分析服务器的响应结果
     * 3. 跳转到小车控制界面
    */
    console.log(this.data.reqURL)

    if (this.data.reqURL == '') {
      wx.showModal({
        title: '提示',
        content: '请先输入正确的服务器地址！',
      })
      return
    }

    // 发起到服务器的GET请求
    wx.request({
      url: this.data.reqURL,
      success: function (res) {
        // 在这里获取POST请求地址，以及视频流地址，然后赋值给全局变量，供control页面调用
        console.log(res.data.match(/url = \"(\S*)\"/)[1])
        console.log(res.data.match(/src=\"(\S*)\"/)[1])
        app.globalData.postURL = res.data.match(/url = \"(\S*)\"/)[1]
        app.globalData.cameraURL = res.data.match(/src=\"(\S*)\"/)[1]

        // 跳转到control页面
        wx.navigateTo({
          url: '/pages/control/control',
        })
      },
      fail: function(res) {
        wx.showModal({
          title: '提示',
          content: '请检查输入的服务器地址！',
        })
      }
    })
  }
})

• index.json：无数据，只有一对打括号

• index.wxml

<!--index.wxml-->
<view>
  <view class="welcome">
    <view class="logo">
      <image style="width: 250rpx; height: 250rpx" src="{{logo}}"></image>
    </view>
    <view>
      <text class="words">{{welcome}}</text>
    </view>
  </view>

  <input class="requestURL" type="text" placeholder="{{PromoteMsg}}" focus=&#39;1&#39; cursor=&#39;10&#39; confirm-type="done" bindinput=&#39;getURL&#39;></input>
  <button class=&#39;enter&#39; bindtap=&#39;enterClicked&#39;>{{enterBtn}}</button>
</view>

• index.wxss

/**index.wxss**/
.welcome{
  display: flex;
  margin-top: 50rpx;
  flex-direction: column;
  align-items: center;
  justify-content: space-between;
}

.requestURL{
  margin: 50rpx 10rpx 30rpx 10rpx;
  border: 1px solid gray;
  font-style: italic;
  font-size: small
}

.enter{
  margin-right: 10rpx;
  width: 150rpx;
  height: 60rpx;
  font-size: small
}

4. control目录

• control.js

// pages/control/control.js
const app = getApp()

Page({

  /**
   * 页面的初始数据
   */
  data: {
    // Car control images
    "forwardBtn": "/res/forward.png",
    "leftBtn": "/res/left.png",
    "rightBtn": "/res/right.png",
    "backLeftBtn": "/res/back-left.png",
    "backRightBtn": "/res/back-right.png",
    "backBtn": "/res/backward.png",

    // Camera control images
    "upBtn": "/res/forward.png",
    "camLeftBtn": "/res/camLeft.png",
    "camRightBtn": "/res/camRight.png",
    "downBtn": "/res/backward.png",
    "resetBtn": "/res/reset.png"
  },

  carMove: function(event) {
    wx.request({
      url: this.data.postURL,
      data: event.currentTarget.dataset.direction,
      method: "POST",
      success: function(res){

      },
      fail: function(res){
        
      }
    })
  },

  carStop: function(event) {
    wx.request({
      url: this.data.postURL,
      data: "S",
      method: "POST",
      success: function (res) {

      },
      fail: function (res) {

      }
    })
  },

  camMove: function(event) {
    wx.request({
      url: this.data.postURL,
      data: event.currentTarget.dataset.direction,
      method: "POST",
      success: function (res) {

      },
      fail: function (res) {

      }
    })
  },

  /**
   * 生命周期函数--监听页面加载
   */
  onLoad: function (options) {
    //this.data.cameraURL = app.globalData.cameraURL
    this.setData({
      cameraURL: app.globalData.cameraURL,
      postURL: app.globalData.postURL
    })
    console.log(this.data.cameraURL)
    console.log("post url in control page: " + app.globalData.postURL)
  },

  /**
   * 生命周期函数--监听页面初次渲染完成
   */
  onReady: function () {
  
  },

  /**
   * 生命周期函数--监听页面显示
   */
  onShow: function () {
    //console.log(wx.getSystemInfoSync().windowWidth)
    //console.log(wx.getSystemInfoSync().windowHeight)
  },

  /**
   * 生命周期函数--监听页面隐藏
   */
  onHide: function () {
  
  },

  /**
   * 生命周期函数--监听页面卸载
   */
  onUnload: function () {
  
  },

  /**
   * 页面相关事件处理函数--监听用户下拉动作
   */
  onPullDownRefresh: function () {
  
  },

  /**
   * 页面上拉触底事件的处理函数
   */
  onReachBottom: function () {
  
  },

  /**
   * 用户点击右上角分享
   */
  onShareAppMessage: function () {
  
  }
})

• control.json

{
  "navigationBarBackgroundColor": "#ffffff",
  "navigationBarTextStyle": "black",
  "navigationBarTitleText": "树莓小车",
  "backgroundColor": "#eeeeee",
  "backgroundTextStyle": "light",
  "enablePullDownRefresh": false,
  "navigationStyle": "custom",
  "disableScroll": true
}

• control.wxml

<!--pages/control/control.wxml-->
<view class=&#39;control&#39;>
  <!-- This image shows the camera view -->
  <image class=&#39;cameraView&#39; src=&#39;http://192.168.1.104:8080/?action=stream&#39; style="z-index:1"></image>

  <!-- The following six images control the car move  -->
  <image class=&#39;button&#39; id=&#39;forward&#39; src=&#39;{{forwardBtn}}&#39; style="position:absolute;z-index:2" bindtouchstart=&#39;carMove&#39; data-direction=&#39;F&#39; bindtouchend=&#39;carStop&#39;></image>
  <image class=&#39;button&#39; id=&#39;left&#39; src=&#39;{{leftBtn}}&#39; style="position:absolute;z-index:2" bindtouchstart=&#39;carMove&#39; data-direction=&#39;L&#39; bindtouchend=&#39;carStop&#39;></image>
  <image class=&#39;button&#39; id=&#39;right&#39; src=&#39;{{rightBtn}}&#39; style="position:absolute;z-index:2" bindtouchstart=&#39;carMove&#39; data-direction=&#39;R&#39; bindtouchend=&#39;carStop&#39;></image>
  <image class=&#39;button&#39; id=&#39;backLeft&#39; src=&#39;{{backLeftBtn}}&#39; style="position:absolute;z-index:2" bindtouchstart=&#39;carMove&#39; data-direction=&#39;BL&#39; bindtouchend=&#39;carStop&#39;></image>
  <image class=&#39;button&#39; id=&#39;backRight&#39; src=&#39;{{backRightBtn}}&#39; style="position:absolute;z-index:2" bindtouchstart=&#39;carMove&#39; data-direction=&#39;BR&#39; bindtouchend=&#39;carStop&#39;></image>
  <image class=&#39;button&#39; id=&#39;back&#39; src=&#39;{{backBtn}}&#39; style="position:absolute;z-index:2" bindtouchstart=&#39;carMove&#39; data-direction=&#39;B&#39; bindtouchend=&#39;carStop&#39;></image>

  <!-- The following images control the camera move  -->
  <image class=&#39;button&#39; id=&#39;up&#39; src=&#39;{{upBtn}}&#39; style="position:absolute;z-index:2" bindtouchstart=&#39;camMove&#39; data-direction=&#39;VU&#39;></image>
  <image class=&#39;button&#39; id=&#39;camLeft&#39; src=&#39;{{camLeftBtn}}&#39; style="position:absolute;z-index:2" bindtouchstart=&#39;camMove&#39; data-direction=&#39;HL&#39;></image>
  <image class=&#39;button&#39; id=&#39;camRight&#39; src=&#39;{{camRightBtn}}&#39; style="position:absolute;z-index:2" bindtouchstart=&#39;camMove&#39; data-direction=&#39;HR&#39;></image>
  <image class=&#39;button&#39; id=&#39;down&#39; src=&#39;{{downBtn}}&#39; style="position:absolute;z-index:2" bindtouchstart=&#39;camMove&#39; data-direction=&#39;VD&#39;></image>
  <image class=&#39;button&#39; id=&#39;reset&#39; src=&#39;{{resetBtn}}&#39; style="position:absolute;z-index:2" bindtouchstart=&#39;camMove&#39; data-direction=&#39;RESET&#39;></image>
</view>

• control.wxss

/* pages/control/control.wxss */

.control {
  width: 100%;
  height: 100%;
  transform: rotate(90deg);
  background-color: #eee;
  justify-content: center;
}

.cameraView {
  margin-left: 0px;
  width: 603px;
  height: 375px;
  background-color: #eee;
  justify-content: center;
}

.button {
  height: 60px;
  width: 60px;
  opacity: 0.3;
}

#forward {
  left: 60px;
  top: 135px;
}

#left {
  left: 0px;
  top: 195px;
}

#right {
  left: 120px;
  top: 195px;
}

#backLeft {
  left: 0px;
  top: 255px;
}

#backRight {
  left: 120px;
  top: 255px;
}

#back {
  left: 60px;
  top: 315px;
}

#up {
  left: 480px;
  top: 195px;
}

#camLeft {
  left: 420px;
  top: 255px;
}

#camRight {
  left: 540px;
  top: 255px;
}

#down {
  left: 480px;
  top: 315px;
}

#reset{
  left: 480px;
  top: 135px
}

5. 工程全局控制

• app.js：实际似乎并没有用到，里面都是工程创建时的默认代码

//app.js
App({
  onLaunch: function () {
    // 展示本地存储能力
    var logs = wx.getStorageSync('logs') || []
    logs.unshift(Date.now())
    wx.setStorageSync('logs', logs)

    // 登录
    wx.login({
      success: res => {
        // 发送 res.code 到后台换取 openId, sessionKey, unionId
      }
    })
    // 获取用户信息
    wx.getSetting({
      success: res => {
        if (res.authSetting['scope.userInfo']) {
          // 已经授权，可以直接调用 getUserInfo 获取头像昵称，不会弹框
          wx.getUserInfo({
            success: res => {
              // 可以将 res 发送给后台解码出 unionId
              this.globalData.userInfo = res.userInfo

              // 由于 getUserInfo 是网络请求，可能会在 Page.onLoad 之后才返回
              // 所以此处加入 callback 以防止这种情况
              if (this.userInfoReadyCallback) {
                this.userInfoReadyCallback(res)
              }
            }
          })
        }
      }
    })
  },
  globalData: {
    userInfo: null,
    postURL: null,
    cameraURL: null
  }
})

• app.json:

{
  "pages": [
    "pages/index/index",
    "pages/control/control"
  ],
  "window": {
    "backgroundTextStyle": "light",
    "navigationBarBackgroundColor": "#fff",
    "navigationBarTitleText": "树莓小车",
    "navigationBarTextStyle": "black",
    "showStatusBar": false
  }
}

• app.wxss:

/**app.wxss**/
.container {
  height: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: space-between;
  padding: 200rpx 0;
  box-sizing: border-box;
}

• project.control.json:

{
	"description": "项目配置文件。",
	"packOptions": {
		"ignore": []
	},
	"setting": {
		"urlCheck": false,
		"es6": true,
		"postcss": true,
		"minified": true,
		"newFeature": true
	},
	"compileType": "miniprogram",
	"libVersion": "2.0.4",
	"appid": "wx18414b9f85bfc895",
	"projectname": "wechat-control",
	"isGameTourist": false,
	"condition": {
		"search": {
			"current": -1,
			"list": []
		},
		"conversation": {
			"current": -1,
			"list": []
		},
		"game": {
			"currentL": -1,
			"list": []
		},
		"miniprogram": {
			"current": -1,
			"list": []
		}
	}
}

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