我正在使用PhoneGap 1.5.0开发Android应用程序。该应用程序将数据存储在本地数据库中，并使用Web服务进行同步。我使用一个按钮单击调用同步数据JavaScript函数。我发现的问题是：这个同步按钮的点击事件会触发两次。单个记录会被上传两次，并且在服务器数据库中的上传时间相同。如何避免这种情况？谢谢。
编辑： 大家好，抱歉回复有些晚了；我忙于一些优先工作。在按钮上单击时调用SyncData()函数。以下是代码：
编辑： 大家好，抱歉回复有些晚了；我忙于一些优先工作。在按钮上单击时调用SyncData()函数。以下是代码：
document.addEventListener("DOMContentLoaded", onDeviceReady, false);
var db;
var maxrecords = 0;
var recordsprocessed = 0;
var urlstart = "http://www.mywebsite.com/";
function onDeviceReady() {
db = window.openDatabase("LocalDB", "1.0", "PhoneGap Demo", 50 * 1024 * 1024);
}
function SyncData() {
maxrecords = 0;
recordsprocessed = 0;
db.transaction(queryDB, errorCB, successCB);
}
function queryDB(tx) {
var entriestoupload = 0;
var profimagetoupload = 0;
//check how many entries are to be synchronized
tx.executeSql('SELECT count(*) as cnt FROM tblEntries WHERE IsUploaded=0', [], function(tx, results) {
entriestoupload = parseInt(results.rows.item(0)['cnt']);
//check how many profile images are to be uploaded
tx.executeSql('SELECT count(*) as cnt FROM tblEntries WHERE IsProfileImageUploaded=0', [], function(tx, results) {
profimagetoupload = parseInt(results.rows.item(0)['cnt']);
//synch proceeds if there is any record which is not sychronised
if (entriestoupload > 0 || profimagetoupload > 0) {
var dataMsg = '';
var porofimgMsg = '';
if (entriestoupload > 0) dataMsg = entriestoupload + ' entry, ';
if (profimagetoupload > 0) porofimgMsg = profimagetoupload + ' profile image ';
// give user exact info about what will be synchronized
if (confirm(dataMsg + porofimgMsg + ' are not synchronized.\n Do you want to start synchronisation? \n Please wait till synch successfull message appears.')) {
//start synchronisation
tx.executeSql('SELECT * FROM tblEntries ORDER BY DateOfRegistration DESC', [], uploadData, errorCB);
}
} else {
alert('All records are already Synchronized.');
}
}, errorCB);
}, errorCB);
}
function uploadData(tx, results) {
var len = results.rows.length;
maxrecords = len;
var Synched = 0;
if (len > 0) {
for (var i = 0; i < len; i++) {
var row = results.rows.item(i);
var LocalId = row['LocalId'];
var DateOfRegistration = getDateTimeformatMySql(String(row['DateOfRegistration']));
var DateOption = getDateTimeformatMySql(String(row['DateOption']));
var VolunteerId = row['VolunteerId'];
var IsUploaded = row['IsUploaded'];
var LiveId = row['LiveId'];
var ProfileImagePath = row['ProfileImagePath'];
var IsProfileImageUploaded = parseInt(row['IsProfileImageUploaded']);
var params = null;
var weburl = null;
if (IsUploaded == 0) {
//set parameters for web service
params = "LocalId=" + LocalId + "&OrganizationName=" + row['OrganizationName'] + "&FirstName=" + row['FirstName'] + "&LastName=" + row['LastName'] + "&EmailAddress=" + row['EmailAddress'] + "&MobileNumber=" + row['MobileNumber'] + "&Country=" + row['Country'] + "&State=" + row['State'] + "&City=" + row['City'] + "&Lattitude=" + row['Lattitude'] + "&Longitude=" + row['Longitude'] + "&Website=" + row['Website'] + "&DateOption=" + DateOption + "&TimeOption=" + row['TimeOption'] + "&NumberOption=" + row['NumberOption'] + +"&RadioOption=" + row['RadioOption'] + "&Details=" + row['Details'] + "&CheckBoxoption=" + row['CheckBoxoption'] + "&DropDownOption=" + row['DropDownOption'] + "&DateOfRegistration=" + DateOfRegistration + "&VolunteerId=" + VolunteerId;
//web service url
weburl = urlstart + "mywebserviceurl";
try {
$.ajax({
async: false,
type: "POST",
url: weburl,
data: params,
dataType: "json",
success: function(data, textStatus, jqXHR) {
if (data.Success == "0") {
alert('web services error:\n' + data.Message);
}
if (data.Success == "1") {
try {
LiveId = parseInt(String(data.LiveId));
IsUploaded = 1;
//Update local database to set IsUploaded and LiveId
tx.executeSql("UPDATE tblEntries SET LiveId= " + LiveId + " ,IsUploaded=1 WHERE LocalId= " + LocalId, [], function(tx, results) {
Synched = Synched + 1; /*alert(LiveId);*/
}, errorCB);
//check if profile image exists or not
if (ProfileImagePath != undefined) {
uploadImage(LiveId, LocalId, ProfileImagePath, '1', '');
}
} catch (e) {
}
}
},
error: function() {
alert("There was an error loading the feed");
}
});
} catch (e) {
}
} else {
//check if data is uploaded and image is not uploaded
if (IsProfileImageUploaded == 0 && ProfileImagePath != undefined) {
uploadImage(LiveId, ShopId, ProfileImagePath, '1', '');
}
}
}
}
} // end of querySucess function
//function to upload image
function uploadImage(LiveId, LocalId, ImagePath, UploadType, CreationDate) {
try {
var options = new FileUploadOptions();
options.fileKey = "file";
options.fileName = ImagePath;
options.mimeType = "image/jpg";
var params = new Object();
params.LiveId = LiveId;
params.LocalId = LocalId;
params.UploadType = UploadType;
params.CreationDate = CreationDate;
options.params = params;
options.chunkedMode = false;
var ft = new FileTransfer();
var url = urlstart + "mywebservice_url_to_uploadimage";
ft.upload(ImagePath, url, win, fail, options, false);
} catch (e) {
console.error("Survey App Err :" + e.message);
}
}
function win(r) {
var jsonresponse = r.response.substring(r.response.indexOf('{'), r.response.indexOf('}') + 1);
var obj = $.parseJSON(jsonresponse);
if (obj.Success == "1") {
var LocalId = parseInt(obj.LocalId);
var UploadType = parseInt(obj.UploadType);
if (UploadType == 1) {
db.transaction(function(tx) {
tx.executeSql("UPDATE tblEntries SET IsProfileImageUploaded=1 WHERE LocalId=?", [LocalId], function(tx, results) {
}, errorCB);
}, errorCB, successCB);
}
}
}
function fail(error) {
alert("There was an error uploading image");
}