数据库 - phonegap前的页面 [英] page before database - phonegap

问题描述

我有一个页面必须显示来自webql数据库的信息。
但是，即使信息位于数据库中，页面也会加载空格。我猜在打开/激活数据库之前填充页面？
有什么我可以做到这一点，减缓页面加载或加快数据库加载吗？

I have a page that has to display information from a websql database. However the page loads with blanks, even though the information is in the database. I am guessing that the page gets populated before the database is open / active? Is there anything I can do so slow the page load or speed up the database load?

推荐答案

与同样的问题。下面是示例db服务功能代码。

I was struggling with the same issue. Below is the sample db service function code.

这是因为web-sql调用是异步的。例如，下面的getItemData是在mapItemRow将结果集转换为所需对象类型之前返回itemData。

Reason this was happening because web-sql calls are asynchronous. For example, below getItemData is returning itemData before mapItemRow converts the resultset into required object type.

getItemData:function(){
            var itemData= [];
            _dbCon.transaction(function (tx) {
            var queryExp = 'SELECT description as Item, amount as Amount from inventory';
                tx.executeSql(queryExp, [],mapItemRow);
            }, dbConnectionFactory.errorDBSql, dbConnectionFactory.successDBSql);

            function mapItemRow(tx, results) {
                console.log('Calling mapItemRow....')
                var len = results.rows.length;
                for (i = 0; i < len; i++) {
                    itemData.push({ITEM: results.rows.item(i).description, Amount: results.rows.item(i).amount});
                }
                return itemData;
            };
        }

我也使用angularJs来解决这个问题我使用$ q和promise功能。让我知道，如果你有兴趣看到的解决方案。

I am also using angularJs so to fix this problem i used $q and promise functionality. Let me know if you are interested to see the solution.

在您的情况下，您可以使用settimeout功能：

In your case you can use settimeout functionality:

var millisecondsToWait = 500;
setTimeout(function() {
    // call your db service
}, millisecondsToWait);

您还可以实现像以下链接中提到的解决方案：
等到条件成立为止？

You can also implement solution like waitfor mentioned in following link: Wait until a condition is true?

希望这可以帮助你。

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