localStorage实现便签小程序

时间:2020-05-15 塞上江南果人气:0

前言：今天写了个小练习，把这几天看的东西巩固一下，在这个程序中用到了localStorage存储和json串的转换。

下面是具体的实现代码：

（1）首先判断是否存在用户，从而显示相应的界面

function isUser()
{
  var storage = window.localStorage;
  if (storage.user != undefined)
  {
    document.getElementById("showmess").style.display = "block";
    document.getElementById("fillmess").style.display = "none";
  }
  else
  {
    document.getElementById("showmess").style.display = "none";
    document.getElementById("fillmess").style.display = "block";
  }  
}

（2）存储用户信息

var pic; //全局变量存储图片信息
/*从本地电脑获得图片*/
 function add_files(files) {
        if (files.length) {
          var file = files[0];
          var reader = new FileReader();
          reader.onload = function(e) {
            document.getElementById("userpic").src = e.target.result;
            pic = e.target.result;
          }
          reader.readAsDataURL(file);
        }
      }
function saveUserMess()
{
  var name = document.getElementById("username").value;
  if (name != "")
  {
    var storage = window.localStorage;
    var jsonObj = {
                name:name,
                icon:pic
              }; 
      var user = JSON.stringify(jsonObj);
      storage.setItem("user",user);
  }
  else
  {
    alert("昵称不为空"); 
  }
}

（3）用户输入便签内容，并保存

function save_diary()
{
 var headle = document.getElementById("headle").value;
 var cont = document.getElementById("diary").value;
 if (headle != "" && cont != "")
 {
  var storage = window.localStorage;
  if (storage.diary != undefined)
  {
   var diary = storage.getItem("diary");
   var jsonObj = JSON.parse(diary);
   var diaryItem = {
        headle:headle,
        diary:cont,
        date:new Date()
       }; 
   jsonObj.push(diaryItem);
   var data = JSON.stringify(jsonObj);
   storage.setItem("diary",data); 
  }

  else
  {
   var jsonObj = [{
        headle:headle,
        diary:cont,
        date:new Date()
       }]; 
   var diary = JSON.stringify(jsonObj);
   storage.setItem("diary",diary);
  }
 }
 else
 {
  alert("标题和内容不为空哦"); 
 }
}

（4）将用户便签信息显示在见面

function showDiary()
{
  var storage = window.localStorage;
  var mess = JSON.parse(storage.user);
  if (storage.diary != undefined)
  {
    var json = JSON.parse(storage.diary);
    var div_id = document.getElementById("diarymess");
    for (var i = 0; i < json.length; i++)
    {

      div_id.innerHTML+='<div><button class="btn btn-success"'+'type="button" id="dropdownMenu" onclick="show(this)"><div class="col-md-4"><img src='+mess.icon+' class="img-circle size" id="userpic"><br><font style="text-align:center">'+mess.name+'</font></div><div class="col-md-8"><h2>'+json[i].headle+'</h2><font>'+json[i].date+'</font></div><span class="caret" style="margin-top:50px;">'+'</span></button><p style="display:none">'+json[i].diary+'</p><div>'; 
    }

  }
}

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