How to use data entered in panel in a Google Doc - GAS - variables

Question

First of all: this site has been a great help already to me, thnx a lot!
In a Google doc I am adding a vertical panel to assist the user in composing and sending a letter. I used the example in this thread and it works fine showing the panel:
function onOpen() {
var app = UiApp.createApplication().setWidth(455).setTitle('User input')
var panel = app.createVerticalPanel().setStyleAttribute('padding','25px')
var label1 = app.createLabel('Your name please');
var box1 = app.createTextBox().setId('Field1').setName('Field1');
panel.add(label1)
panel.add(box1)
var pasteHandler = app.createServerChangeHandler('readTextbox');
pasteHandler.addCallbackElement(panel);
var clickButton=app.createButton('OK').setId('PasteTest').addClickHandler(pasteHandler)
panel.add(clickButton);
app.add(panel);
DocumentApp.getUi().showSidebar(app);
//I want to arrive here only after a value is entered in the panel
// ... follows more code ...
}
function readTextbox(e){
var app = UiApp.getActiveApplication();
var boxValue=e.parameter.Field1;
//how to get this e.parameter values (more than one..) to the main function
return app;
}
My question is: how to make the main function wait after 'showSidebar' until a value is entered?
Second question: how to use this input outside the handler, e.g. for writing in the document? I found a workaround by writing the fields to a spreadsheet within the handler, but that's not very elegant ;-)
Many thanks in advance...

Answer 1

You can't make the onOpen() function wait, but you don't need to. You have a click handler and the readTextbox() function. And you don't need to get the readTextbox() function to branch back to the onOpen() function. If there are conditions that require branching to different functions depending on what the user does, then you can create a new function.
You can call a function from a function just by using it's name, and parenthesis after the name and a semicolon.
function readTextbox(e){
var app = UiApp.getActiveApplication();
var boxValue=e.parameter.Field1;
anotherCoolFunction(boxValue);
//how to get this e.parameter values (more than one..) to the main function
return app;
}
function anotherCoolFunction(someArg){
Logger.log('Some Arg: ' + someArg);
}
In the above code, after the name is entered and the user clicks the button, the readTextBox function runs, then the readTextBox() function calls the anotherCoolFunction(boxValue); function and passes the variable boxValue to the anotherCoolFunction().
You can verify that it works, by looking at the log. Choose the View Menu, and the Logs menu item to display the Log output.