How to use the data store to set a toolbar title in Sencha Touch

I am trying to set the toolbar item dynamically. So far I have a back button that resets the toolbar title to 'start' if the user chooses to go back.

But the following code won't work:

menuList.on('itemtap', function(dataView, 开发者_StackOverflow中文版index, item, e){
     viewport.dockedItems.items[0].setTitle('{title}');
});

It tries to use a variable called 'title' out of my data store array. This works great for providing text to my Ext.List items. But the above code sets the toolbar title to the string '{title}' without even thinking of it being a variable.

Can you help me out?

List's use templates so items within curley braces get evaluated... you'll need to pass a reference to a variable without quotes. You haven't provided enough code for me to tell you where that information would be. If you already have a variable in scope called title that you put the data into then you can just reamove the '{ and }' ... otherwise you'll need to get the data you need from your store through some means, like Ext.StoreMgr or [appname].stores

Two things. 1) You will really want to get used to digging into the ST source code. In this case, if you look at the code for "setTitle", you will see that its argument is interpreted as straight HTML, not a template. So you can't use curly bracket syntax here. 2) Note that the type of the "item" argument to the event handler is an Element (i.e. ST's representation of the DOM object, not the selected datastore object. So that's not going to help you. However, the "index" arg gives you an easy way to get the appropriate object from the store. i.e.

[appname].stores.pages.getAt(index).title

I really don't know why, but it works if you put up to variables: One for the record and one for the value inside that record. There is a detailed explanation in the sencha.com-forum