歌曲管理

2019-10-13

字数统计: 481字 | 阅读时长: 2分

阅读量 33

函数封装歌曲管理

增

function addSong(song){
// songList.push(song);
// }
//
// addSong({
// songName:"take me to your heart",
// singer:"迈克学摇滚"
// });

删

function removeSong(songName){
var song = selectSong(songName);
var index = songList.indexOf(song);
songList.splice(index, 1);

// for (var i = 0; i < songList.length; i++) {
// var song = songList[i];
// if(song.songName == songName){
// //splice(起始索引,删几个)
// songList.splice(i, 1);
// }
// }
}

removeSong("李白");

改

function updateSong(songName, singer) {

var song = selectSong(songName);
song.singer = singer;

//遍历歌曲列表，找到要修改的对象
// for (var j = 0; j < songList.length; j++) {
// var song = songList[j];
// //判断每次遍历的对象的歌名，和要找的歌名是不是一一致，如果一致，就是我们要找的对象
// if(song.songName == songName){
// //对找到的对象进行修改
// song.singer = singer;
// }
// }
}
//
// updateSong("演员","薛之谦");
// console.log(songList);

查

function selectSong(songName) {
for (var k = 0; k < songList.length; k++) {
var song = songList[k];
if(song.songName == songName){
return song;
}
}
return null;
}

面向对象封装歌曲管理

在当前对象的方法中，调用当前对象的其他方法，需要使用this
例如在 removeSong方法中调用 selectSong this.selectSong

function SongManager(){
this.songList = null;
}
SongManager.prototype = {
init:function (songList) {
this.songList = songList;
},

addSong: function (song){
this.songList.push(song);
},

removeSong:function (songName){
var song = this.selectSong(songName);
if(song == null){
throw "您要删除的歌曲不存在！请重新尝试";
}
var index = this.songList.indexOf(song);
this.songList.splice(index, 1);
},

updateSong: function (songName, singer) {
var song = this.selectSong(songName);
if(song == null){
throw "您要修改的歌曲不存在！请重新尝试";
}
song.singer = singer;
},

selectSong: function (songName) {
for (var k = 0; k < this.songList.length; k++) {
var song = this.songList[k];
if(song.songName == songName){
return song;
}
}
return null;
}
};
调用
var pwbDEManager = new SongManager();
pwbDEManager.init([
{
songName:"青藏高原",
singer:"潘文斌"
},
{
songName:"我的换板鞋，摩擦摩擦最时尚",
singer:"约翰逊，庞麦郎"
}
]);
gjbDEManager.removeSong("两只老虎");