javascript - 我可以在哪个文件中放置一个脚本来清除 Titanium 应用程序的缓存

Question

我编写了一个脚本，允许您删除应用程序缓存中的属性，但是我只需要在安装应用程序时运行一次该脚本。有人有想法，谢谢

var executed = 0; 
if(executed === 0){
    Ti.App.Properties.removeProperty("My_Property");
    executed++; 
}

Answer 1

您可以在应用程序 session 中保留一些值的唯一方法是 Ti.App.Properties 或 sql 数据库。因此，您可以通过以下两种方式进行操作:

解决方案 1:使用另一个属性来知道您已经删除了所需的属性。

// for first time installation, the default value (or 2nd parameter) will be false as you have not deleted the property yet
var isDeleted = Ti.App.Properties.getBool('My_Property_Deleted', false);

if (isDeleted) {
    Ti.App.Properties.removeProperty("My_Property");

    // since you have deleted it, now set it to true so this 'if' block doesn't runs on any next app session
    Ti.App.Properties.setBool('My_Property_Deleted', true);

} else {
    // you have already deleted the property, 'if' block won't run now
}

解决方案 2:创建一个新数据库或使用您的应用预加载已发布的数据库。

// Titanium will create it if it doesn't exists, or return a reference to it if it exists (after first call & after app install)
var db = Ti.Database.open('your_db');

// create a new table to store properties states
db.execute('CREATE TABLE IF NOT EXISTS deletedProperties(id INTEGER PRIMARY KEY, property_name TEXT);');

// query the database to know if it contains any row with the desired property name
var result = db.execute('select * from deletedProperties where name=?', "My_Property");

if (result.rowCount == 0) { // means no property exists with such name
    // first delete the desired property
    Ti.App.Properties.removeProperty("My_Property");

    // insert this property name in table so it can be available to let you know you have deleted the desired property
    db.execute('insert into deletedProperties(name) values(?)', "My_Property");

} else {
    // you have already deleted the property, 'if' block won't run now
}

// never forget to close the database after no use of it
db.close();

也可以有其他方法，但这两种方法可以满足您的需求。 <强> Read more about Ti.Database here