微信小程序实战–集阅读与电影于一体的小程序项目（三）

14.wx.showToast交互反馈

post-detail.js添加个消息提示框

onCollectionTap: function(ev) {    var postsCollected = wx.getStorageSync('posts_Collected')    var postCollected = postsCollected[this.data.currentPostId]    postCollected = !postCollected;    postsCollected[this.data.currentPostId] = postCollected;    // 更新文章是否收藏的缓存值    wx.setStorageSync('posts_Collected', postsCollected)    // 更新数据绑定变量，实现切换图片    this.setData({      collected: postCollected    })    wx.showToast({      title: postCollected ? "收藏成功" : "取消成功",      duration: 1000,      icon: "success"    })  }

效果

15.音乐播放功能

音乐播放API文档

在posts-data.js里面给每篇文章添加一个music属性

 music: {    url: "http://music.163.com/song/media/outer/url?id=108242.mp3",    title: "她说-林俊杰",    coverImg: "http://y.gtimg.cn/music/photo_new/T002R150x150M000001TEc6V0kjpVC.jpg?max_age=2592000"  }

post-detail.wxml

没播放音乐就显示文章图片，播放音乐就显示音乐歌手图片
绑定事件，添加播放和暂停音乐以及图片切换功能

 <!-- <image class="head-image" src="{{postData.headImgSrc}}"></image> -->  <image class='head-image' src="{{isPlayingMusic?postData.music.coverImg:postData.headImgSrc}}"></image>  <image catchtap='onMusicTap' class='audio' src="{{isPlayingMusic? '/images/music/music-stop.png': '/images/music/music-start.png'}}"></image>

post-detail.js

// 播放音乐  onMusicTap: function (ev) {    var currentPostId = this.data.currentPostId;    var postData = postsData.postlist[currentPostId];    var isPlayingMusic = this.data.isPlayingMusic;    if (isPlayingMusic) {      wx.pauseBackgroundAudio();      this.setData({        isPlayingMusic: false      })    }    else {      wx.playBackgroundAudio({        dataUrl: postData.music.url,        title: postData.music.title,        coverImgUrl: postData.music.coverImg,      })      this.setData({        isPlayingMusic: true      })    }  }

16.监听音乐播放事件

监听音乐播放文档

post-detail.js的onLoad函数里面添加监听事件

var that = this;    wx.onBackgroundAudioPlay(function(){      that.setData({        isPlayingMusic: true      })    });    wx.onBackgroundAudioPause(function () {      that.setData({        isPlayingMusic: false      })    });  },

绑定监听事件后，播放按钮的状态就可以同步切换了

17.完善音乐播放功能

在文章详情页，点击播放音乐后，然后返回到文章列表页，再进到详情页，发现播放按钮是暂停状态，这是因为应用程序存在生命周期，下面就解决这个问题。

app.js绑定一个全局的变量（音乐播放状态）

App({  globalData: {    g_isPlayingMusic: false,    g_currentMusicPostId: null,  },})

post-detail.js

var app = getApp();Page({  data: {    isPlayingMusic: false  },  onLoad: function(options) {    .    .    .    if (app.globalData.g_isPlayingMusic && app.globalData.g_currentMusicPostId === postId) {      this.setData({        isPlayingMusic: true      })    }    this.setMusicMonitor()  },  setMusicMonitor:function(){    var that = this;    wx.onBackgroundAudioPlay(function () {      that.setData({        isPlayingMusic: true      })      app.globalData.g_currentMusicPostId = that.data.currentPostId      app.globalData.g_isPlayingMusic = true    });    wx.onBackgroundAudioPause(function () {      that.setData({        isPlayingMusic: false      })      app.globalData.g_currentMusicPostId = null      app.globalData.g_isPlayingMusic = false    });    },

18.轮播图跳转到文章详情

post.wxml

<swiper catchtap='onSwiperTap' indicator-dots='true' autoplay='true' interval='2000'>

post.js

onSwiperTap(event) {    var postId = event.target.dataset.postid    wx.navigateTo({      url: 'post-detail/post-detail?id=' + postId    })  },