Question

Hey I’m using phonegap databases, and trying to understand why my callback is called before the process method has finished, below is the js code and the log which indicates my claim

Here is the code:(Method that is called first, is insertIntoDB(x,y);)

    var databaseVersion = 1;

function createTable(tx, tableName, tableColumns){
    var sqlStatement = 'CREATE TABLE IF NOT EXISTS '+tableName+' (_id unique, ' + tableColumns+')';
    tx.executeSql('DROP TABLE IF EXISTS '+tableName);
    tx.executeSql(sqlStatement);
    console.log('now doInsertion (if successful should be called');
}

function createMenuDataBase(tx){
    var tableName ="element";
    var tableColumns = ["name", "resource","remoteData", "picture", "pageId", "type", 
        "localAction", "replaceText", "textSize", "textColor","background", "sortOrder"];
    createTable(tx, tableName, tableColumns);
}



function insertIntoDB(tableName,json){
    checkDatabaseVersion(doInsertion,tableName,json);
}

function doInsertion(dbName,json){
    console.log('starting doInsertion');
    var sqlStart = "INSERT INTO "+dbName+" (";
    var sqlEnd =");"
    $.each(json.list, function(i, object) {
        var first = true;
        var columns="";
        var values = ") VALUES ("

        for (property in object) {
            //            alert(property);
            if(property!=undefined){

                if(first){
                    columns +=property;
                    values +=object[property];
                    first=false;
                } else {   
                    columns += ', '+property;
                    values +=', '+object[property];
                }
            }
        }
        console.log(sqlStart+columns+values+sqlEnd);
    });
}

function checkDatabaseVersion(callback,dbName,json){
    var localDatabaseVersion = localStorage.getItem("localDatabaseVersion");
    alert(localDatabaseVersion);
    if(localDatabaseVersion == 'undefined' || localDatabaseVersion == null){
        var db = window.openDatabase("Database", "1.0", "PhoneGap Demo", 200000);
        db.transaction(createMenuDataBase, errorCB, callback(dbName,json));


    //localStorage.setItem("localDatabaseVersion",databaseVersion);
    }
}

And here is the logcat from cordova/my app:

08-01 12:09:02.857: D/DroidGap(24433): onMessage(spinner,stop)
08-01 12:09:03.467: D/CordovaLog(24433): starting doInsertion
08-01 12:09:03.467: D/CordovaLog(24433): file:///android_asset/www/js/Database.js: Line 24 : starting doInsertion
08-01 12:09:03.472: D/CordovaLog(24433): INSERT INTO element (name, resource, id, type, appId, sortOrder, background, picture, textColor, remoteData, pageId, localAction, replaceText, active, textSize) VALUES (menu0.9747386311565038, null, 9765, img, 1, 0, null, /content/picture/menu/product, null, null, mainMenu.menu, showProductCatalog(product), null, Y, 0);
08-01 12:09:03.477: D/CordovaLog(24433): file:///android_asset/www/js/Database.js: Line 46 : INSERT INTO element (name, resource, id, type, appId, sortOrder, background, picture, textColor, remoteData, pageId, localAction, replaceText, active, textSize) VALUES (menu0.9747386311565038, null, 9765, img, 1, 0, null, /content/picture/menu/product, null, null, mainMenu.menu, showProductCatalog(product), null, Y, 0);
08-01 12:09:03.477: D/CordovaLog(24433): INSERT INTO element (name, resource, id, type, appId, sortOrder, background, picture, textColor, remoteData, pageId, localAction, replaceText, active, textSize) VALUES (menu0.9847155498013517, null, 9753, img, 1, 1, null, /content/picture/menu/social, null, null, mainMenu.menu, showSocialMedia(socialmedia), null, Y, 0);
08-01 12:09:03.477: D/CordovaLog(24433): file:///android_asset/www/js/Database.js: Line 46 : INSERT INTO element (name, resource, id, type, appId, sortOrder, background, picture, textColor, remoteData, pageId, localAction, replaceText, active, textSize) VALUES (menu0.9847155498013517, null, 9753, img, 1, 1, null, /content/picture/menu/social, null, null, mainMenu.menu, showSocialMedia(socialmedia), null, Y, 0);
08-01 12:09:03.482: D/CordovaLog(24433): INSERT INTO element (name, resource, id, type, appId, sortOrder, background, picture, textColor, remoteData, pageId, localAction, replaceText, active, textSize) VALUES (menu0.5451258043474583, null, 9759, img, 1, 2, null, /content/picture/menu/store, null, null, mainMenu.menu, menu(store), null, Y, 0);
08-01 12:09:03.482: D/CordovaLog(24433): file:///android_asset/www/js/Database.js: Line 46 : INSERT INTO element (name, resource, id, type, appId, sortOrder, background, picture, textColor, remoteData, pageId, localAction, replaceText, active, textSize) VALUES (menu0.5451258043474583, null, 9759, img, 1, 2, null, /content/picture/menu/store, null, null, mainMenu.menu, menu(store), null, Y, 0);
08-01 12:09:03.482: D/CordovaLog(24433): INSERT INTO element (name, resource, id, type, appId, sortOrder, background, picture, textColor, remoteData, pageId, localAction, replaceText, active, textSize) VALUES (menu0.6883956226802171, null, 9762, img, 1, 3, null, /content/picture/menu/showroom, null, null, mainMenu.menu, showCollection(collection), null, Y, 0);
08-01 12:09:03.482: D/CordovaLog(24433): file:///android_asset/www/js/Database.js: Line 46 : INSERT INTO element (name, resource, id, type, appId, sortOrder, background, picture, textColor, remoteData, pageId, localAction, replaceText, active, textSize) VALUES (menu0.6883956226802171, null, 9762, img, 1, 3, null, /content/picture/menu/showroom, null, null, mainMenu.menu, showCollection(collection), null, Y, 0);
08-01 12:09:03.487: D/CordovaLog(24433): INSERT INTO element (name, resource, id, type, appId, sortOrder, background, picture, textColor, remoteData, pageId, localAction, replaceText, active, textSize) VALUES (menu0.21612715546682493, null, 9768, img, 1, 4, null, /content/picture/menu/beskeder, null, null, mainMenu.menu, showNotificationList(notificationList), null, Y, 0);
08-01 12:09:03.487: D/CordovaLog(24433): file:///android_asset/www/js/Database.js: Line 46 : INSERT INTO element (name, resource, id, type, appId, sortOrder, background, picture, textColor, remoteData, pageId, localAction, replaceText, active, textSize) VALUES (menu0.21612715546682493, null, 9768, img, 1, 4, null, /content/picture/menu/beskeder, null, null, mainMenu.menu, showNotificationList(notificationList), null, Y, 0);
08-01 12:09:03.497: D/CordovaLog(24433): now doInsertion (if successful should be called
08-01 12:09:03.497: D/CordovaLog(24433): file:///android_asset/www/js/Database.js: Line 7 : now doInsertion (if successful should be called

Answer 1

You are calling the callback instead of passing it:

db.transaction(createMenuDataBase, errorCB, callback(dbName,json));

callback(dbName,json) //Calls the function and passes the result to `db.transaction` as callback but it's not a function since the result is not a function.

Try this:

db.transaction(createMenuDataBase, errorCB, callback);

Or in case callback needs those arguments then:

db.transaction(createMenuDataBase, errorCB, callback.bind( null, dbName, json ));