如何在添加新列表之前删除所有元素 [英] how to remove all element before adding the new in list

问题描述

你好



我正在添加一些关于数据库问题的数据添加后我需要在列表视图上显示。我需要在再次渲染之前从列表中删除所有数据.how从列表中删除数据？



Hete是我的代码

Hello

I am adding some data on data base problem After adding i need to show on list view.I need to remove all data from list before rendering again .how to remove data from list?

Hete is my code

$(document).ready(function() {
                   
                     $.mobile.loading('hide');
                     onDeviceReady();
                     });  

//document.addEventListener("deviceready", onDeviceReady, false);
    var db = "";
     //will create database Dummy_DB or open it
 
    //function will be called when device ready
    function onDeviceReady(){
         db = window.openDatabase("Casepad", "1.0", "Casepad", 200000);
         db.transaction(queryDB,errorCB);
       
       //   db.transaction(populateDB, errorCB, successCB);
    }
    function insertData(){
    db.transaction(populateDB, errorCB, successCB);
    }
   
    //create table and insert some record
    function populateDB(tx) {
        tx.executeSql('CREATE TABLE IF NOT EXISTS CaseTable (id INTEGER PRIMARY KEY AUTOINCREMENT, CaseName TEXT NOT NULL,CaseDate INTEGER ,TextArea TEXT NOT NULL)');
        tx.executeSql('INSERT INTO CaseTable(CaseName,CaseDate,TextArea) VALUES ("'+$('#caseNameValue').val()+'", "'+$('#caseDate').val()+'","'+$('#caseTextArea').val()+'")');
    }
 
    //function will be called when an error occurred
    function errorCB(err) {
        alert("Error processing SQL: "+err.code);
    }
 
    //function will be called when process succeed
    function successCB() {
        alert("success!");
        db.transaction(queryDB,errorCB);
    }
 
    //select all from SoccerPlayer
    function queryDB(tx){
        tx.executeSql('SELECT * FROM CaseTable',[],querySuccess,errorCB);
    }
 
    function querySuccess(tx,result){
     var len = result.rows.length;
     
      for (var i=0; i<len;>              $('#folderData').append(
               '<ul><li class="row" id="' + i + '">' + '<a href="#">' + '<img src="img/Blue-Folder.png">' + '<h2>'+result.rows.item(i).CaseName+'</h2>' + '<p>'+result.rows.item(i).CaseDate+'</p>' + '<p>'+result.rows.item(i).TextArea+'</p>'+'<span class="ui-li-count">'+ i+'</span></a>' + '</li></ul>'
            );
        } 
        $('#folderData').listview('refresh');
 
    }

   $("#Cancel").click(function() {
                    $('.ui-dialog').dialog('close')
                    $.mobile.changePage($("#Home"), {
                    transition: "pop",
                    reverse: false,
                    changeHash: false
                   });
                   });
                   
                    
                   $("#CancelSettingButton").click(function() {
                   $.mobile.changePage($("#Home"), {
                    transition: "slide",
                    reverse: false,
                    changeHash: false
                    });
                    });

<！ - < ------------------ -Cancel按钮功能结束-----------------------------------------> - >

<！-----------------------添加按钮功能----------- ----------------------------------------->

<!--<-------------------Cancel Button Functionality End----------------------------------------->-->
<!-----------------------Add Button Functionality---------------------------------------------------->

$("#AddButton").click(function() {
  var isvalid=true;
  if(isvalid){

  insertData();
  $.mobile.changePage($("#Home"), {
  transition: "slide",
  reverse: false,
  changeHash: false
  });
   }
 });

推荐答案

（ document ）。ready（ function （）{

(document).ready(function() {

.mobile.loading（' hide'）;
onDeviceReady（）;
}）;

// document.addEventListener（deviceready，onDeviceReady，false）;
var db = ;
// 将创建数据库Dummy_DB或打开它

< span class =code-comment> // 设备就绪时将调用函数
function onDeviceReady（）{
db = window .openDatabase（ Casepad， 1.0， Casepad， 200000 ）;
db.transaction（queryDB，errorCB）;

// db.transaction（populateDB，errorCB，successCB）;
}
function insertData（）{
db.transaction（populateDB，errorCB，successCB）;
}

// 创建表并插入一些记录
function populateDB（tx）{
tx.executeSql（' CREATE TABLE IF NOT NOT EXISTS CaseTable（id INTEGER PRIMARY KEY AUTOINCREMENT，CaseName TEXT NOT NULL，CaseDate INTEGER，TextArea TEXT NOT NULL）'）;
tx.executeSql（' INSERT INTO CaseTable（CaseName，CaseDate，TextArea）VALUES（'' +

.mobile.loading('hide'); onDeviceReady(); }); //document.addEventListener("deviceready", onDeviceReady, false); var db = ""; //will create database Dummy_DB or open it //function will be called when device ready function onDeviceReady(){ db = window.openDatabase("Casepad", "1.0", "Casepad", 200000); db.transaction(queryDB,errorCB); // db.transaction(populateDB, errorCB, successCB); } function insertData(){ db.transaction(populateDB, errorCB, successCB); } //create table and insert some record function populateDB(tx) { tx.executeSql('CREATE TABLE IF NOT EXISTS CaseTable (id INTEGER PRIMARY KEY AUTOINCREMENT, CaseName TEXT NOT NULL,CaseDate INTEGER ,TextArea TEXT NOT NULL)'); tx.executeSql('INSERT INTO CaseTable(CaseName,CaseDate,TextArea) VALUES ("'+

（' #caseNameValue'）。val（ ）+ ' ，' +

('#caseNameValue').val()+'", "'+

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