回调的processmethod之前调用

Question

嘿，我使用PhoneGap的数据库，并试图理解为什么我的回调被调用过程方法完成之前，下面的JS代码和日志这表明我的要求

这里验证码：（方法是先叫，是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); 
    } 
} 

这里是从科尔多瓦/我的应用程序的logcat的：

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

要调用回调instea它传递的d：

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. 

试试这个：

db.transaction(createMenuDataBase, errorCB, callback); 

或者在callback需要这些参数则情况：

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