as3 Text Field formatting issue - actionscript-3

Question

I have a problem with formatting the text field. I have buttons + and - to size of text. TextField class has property defaultTextField for new text formatting. And when I change defaultTextFormat size property - whole text's size changes. I have searched for solution everywhere and I haven't found it yet. Text editor WISWYG (I am not sure if name is right) is working well with just changing defaultTextFormat property while I have issue. Maybe it happens because of difference between flash and AIR (editor on flash and my app on AIR). Please help.
Here code to set/get TextFormat:
public function set selectionTextFormat(value:TextFormat):void {
var begin:int = _textField.selectionBeginIndex;
var end:int = _textField.selectionEndIndex;
if (begin == end)
{
_textField.defaultTextFormat = value;
}
else
{
_textField.setTextFormat(value, begin, end);
}
}
public function get selectionTextFormat():TextFormat
{
var begin:int = _textField.selectionBeginIndex;
var end:int = _textField.selectionEndIndex;
if (begin == end)
{
return _textField.defaultTextFormat;
}
return _textField.getTextFormat(begin, end);
}
And code to change format:
private function setFormat(property:String, value:*):void
{
var tf:TextFormat = TextFormatter.TF.selectionTextFormat;
tf[property] = value;
TextFormatter.TF.selectionTextFormat = tf;
}
EDIT : IMAGE ON DROPBOX FOR EXPLANATION:
https://dl.dropboxusercontent.com/u/237572639/Capture.PNG
EDIT 2: IMAGE OF WHAT I NEED (CODE IS ABSOLUTELY SAME!) (WYSIWYG editor)
https://dl.dropboxusercontent.com/u/237572639/WYSIWYG.PNG

Answer 1

To change all future typed text, you can try this code ( the result is visible here ):
var text_input:TextField = new TextField();
text_input.border = true;
text_input.type = 'input';
text_input.text = 'hello world!';
addChild(text_input);
var new_fmt:TextFormat = new TextFormat();
btn_color.addEventListener(
MouseEvent.CLICK,
function(e:MouseEvent):void {
// set the new text color
new_fmt.color = 0xFF0000;
}
)
btn_size.addEventListener(
MouseEvent.CLICK,
function(e:MouseEvent):void {
// set the new text size
new_fmt.size = int(txt_size.text)
}
)
text_input.addEventListener(Event.CHANGE, function(e:Event):void {
text_input.setTextFormat(new_fmt, text_input.caretIndex-1);
})
Of course, this is just a manner to do what you want, you have to adapt it to your need and improve it.