在JavaScript函数中从SQL查询中检索变量(重写)

我在Apache Cordova收集数据并将其发送到web服务器的移动应用程序工作。我想通过main函数

重写代码，使其更集中、更清晰

//main function launched by a button
function sendData(){
    //set all var as suggested
    var content = '';
    var photoList = [];
    var fileName = '';
    //call children functions
    generateCsv(); // 1st child function
    saveCSV();     // 2nd child function
    uploadFile();  // 3rd child function
 }

第一个函数从数据库中提取数据，并为上面的var

function generateCsv() { // 1st child function
    db.transaction(function(tx) {
        tx.executeSql(selectAllStatement, [], function(tx, result) {
            //do something I do not understand really... but work!
            // but set value to var!!
            console.log(content); //the new value is set correctly!!
        });
    }); 
}

现在，如果我尝试在主函数中的下一个函数中记录我的三个var的值，我不会收到generateCsv函数所做的更改…

function saveCSV() { // 2nd child function
    console.log(fileName); //----not updated 
    console.log(content);  //----not updated 
    console.log(photoList);//----not updated
    //do something with my vars!
}

最后一个子函数将上传文件

function uploadFile(){ 3rd child function
    //do something and upload....
}

代码完整:

//------------------SEND DATA----------------->>
function sendData(){
    var content = 'id,wateres,source,s_date,latitude,longitude,top,pump,pump_manual,other_pump,operator,operator_type,condition,disused,abandoned,access,water_presence,drinking_water,fee,fixme,note,photo,exif'n';
    var fileName = '';
    var date = new Date().toString();
    var photoList = [];
    generateCsv();
}

//---------------GENERATE CSV FILE--------------------->>
function generateCsv() {
    db.transaction(function(tx) {
        tx.executeSql(selectAllStatement, [], function(tx, result) {
            dataset = result.rows;
            if (dataset.length!=0){
                for (var i = 0, item = null; i < dataset.length; i++) {
                    item = dataset.item(i);
                    //uploadPhoto(item['photo']);
                    photoList.push(item['photo']);
                    var exif = item['exif'].replace(/('r'n|'n|'r)/gm, " | ");
                    exif = exif.replace(/,/g, '.');
                    content += item['id']+ ',' 
                            + item['wateres'] + ',' 
                            + item['source'] + ',' 
                            + item['s_date'] + ',' 
                            + item['lat'] + ',' 
                            + item['lon'] + ',' 
                            + item['top'] + ',' 
                            + item['pump'] + ',' 
                            + item['pump_manual'] + ',' 
                            + item['other_pump'] + ',' 
                            + item['operator'] + ',' 
                            + item['operator_type'] + ',' 
                            + item['condition'] + ',' 
                            + item['disused'] + ',' 
                            + item['abandoned'] + ',' 
                            + item['access'] + ',' 
                            + item['water_presence'] + ',' 
                            + item['drinking_water'] + ',' 
                            + item['fee'] + ',' 
                            + item['fixme'] + ',' 
                            + item['note'] + ',' 
                            + item['photo'] + ',' 
                            + exif + ''n';
                    fileName = item['source'] + '|' + date;
                }
                fileName = fileName.replace(/' /g, "_");
                fileName = fileName.replace(/',/g, "");
                fileName = fileName.replace(/':/g, "-")+'.csv';
                $('#message').html('<p><strong>Data have been collected.</strong> </p>');
                saveCSV();
            }
        });
    });
}
//--------------------------SAVE CSV ------------------

function saveCSV() {
    console.log(fileName);
            var fileObject;
            document.addEventListener("deviceready", onDeviceReady, true);
            function onDeviceReady() {
                window.requestFileSystem(LocalFileSystem.TEMPORARY, 0, onFileSystemSuccess, fail);
            }
            function onFileSystemSuccess(fileSystem) {
                fileSystem.root.getFile(fileName, { create: true, exclusive: false },
                    gotFileEntry, fail);
            }
            function gotFileEntry(fileEntry) {
                fileObject = fileEntry;
                $('#saveFile_csv').on('click', function() {
                    saveFileContent();
                    //uploadFile(fileName);
                });
            }
            function saveFileContent() {
                fileObject.createWriter(gotFileWriter, fail);
            }
            function gotFileWriter(writer) {
                var myText = document.getElementById('my_text').value + content;
                writer.write(myText);
                writer.onwriteend = function(evt) {
                    $('#message').html('<p>File contents have been written.<br /><strong>File path:</strong> ' + fileObject.fullPath + '</p>');
                    var reader = new FileReader();
                };
            }
            function fail(error) {
                alert('fail to write file code = ' + error.code);
            }
}
//----------------UPLOAD-CSV------------------------>>
function uploadFile(fileName) {
    var fileURL = "///storage/emulated/0/Android/data/com.app/cache/"+fileName;
    function win(r) {
        console.log("Code = " + r.responseCode);
        console.log("Response = " + r.response);
        console.log("Sent = " + r.bytesSent);
        $('#contents').html('<strong>File uploaded</strong><br>'+ new Date() );
    }
    function fail(error) {
        alert("An error has occurred uploading file: Code = " + error.code);
        console.log("upload error source: " + error.source);
        console.log("upload error target: " + error.target);
    }
    var uri = encodeURI("http://www.website.com/upload.php");
    var options = new FileUploadOptions();
    options.fileKey="file";
    options.fileName=fileURL.substr(fileURL.lastIndexOf('/')+1);
    options.mimeType="text/plain";
    var headers={'headerParam':'headerValue'};
    options.headers = headers;
    var ft = new FileTransfer();
    ft.upload(fileURL, uri, win, fail, options);
    $('#contents').html('<strong>Whait upload confirmation...</strong>');
}

谢谢! !