Question

(Flex 3) I have a TextArea component which needs to hold the user’s clipboard content. The TextArea does the job relatively well for most cases but when pasting a large amount of data, I can’t seem to get the content in the component at all due to the script execution timeout.

I’ve done a fair deal on investigation to try and hopefully find how I could make this work.
I found that the TextArea is using a IUITextField (which is in my case an instance of TextField at runtime) do handle the job of obtaining the pasting data and then throws an event when it is done.

I have found no way to take a look at the source of TextField as it is a class in the playerglobal.swc library.

Is there a way for me to maybe see the source of that class or is there something I’m missing in my approach to figure out a way to make this work?

P.S: I know there would be alternate way to achieve the results I’m looking for but I would like to make this particular solution work.

Answer 1

Its impossible with such large texts (you mentioned that the text is around 7MB).

If you look at the source of mx:TextArea, it inserts text simply be setting its TextField text property to the string you entered:
From TextArea.as around line 2050:

 if (textChanged || htmlTextChanged)
    {
        // If the 'text' and 'htmlText' properties have both changed,
        // the last one set wins.
        if (isHTML)
            textField.htmlText = explicitHTMLText;
        else
            textField.text = _text;

        textFieldChanged(false, true)

        textChanged = false;
        htmlTextChanged = false;
    }

If you make a sample app with a TextField and try to set its text property with a large string, you will get script timeouts. (i got timeout when i tried it with a string length of 1MB):

   import flash.text.TextField;
    tf = new TextField();
    addChild(tf);
    tf.multiline = true;
    tf.wordWrap = true;
    tf.width= 600
    tf.height = 500
    var str:String = "";
    for (var i:int=0; i<100000; i++) {
        str = str+"0123456789"
    }
    tf.text = str

This is the simplest possible way to display text, and it timeouts. Flex will try to do a dozen of more things with this textfield before laying out…so it will give up at much smaller size texts too.

The only possible solution is to make a custom textfield, and add the text gradually – Adobe recommends to use TextField.appendText():

import flash.text.TextField;
public function test(){
    tf = new TextField();
    addChild(tf);
    tf.multiline = true;
    tf.wordWrap = true;
    tf.width= 600
    tf.height = 500
    addEventListener(Event.ENTER_FRAME,onEF);
}

private var cnt:int = 0;

private function onEF(event:Event):void{
    if (cnt>200) return;
    trace (cnt);
    var str:String = "";
        //pasting around 50K at once seems ideal.
    for (var i:int=0; i<5000; i++) {
        str = str+"0123456789"
    }
    tf.appendText(str);
    cnt++;
}

This script manages to add 10MB of text into the TextField… although after adding 1MB it gets increasingly slower (it took around 1 sec for an iteration at the end). And if you try to do anything with this textfield (for example resizing, modifying text not with appendText(), adding it to the stage after its complete…) you will get script timeout.

So the complete solution is to capture the paste event canvas wrapper trick (William’s solution), and then add the text gradually to a custom component, that uses appendText to add text. (use flash.text.TextField, and add it to the stage with mx_internal::$addChild() ). I have not tested, whether you can remove the resulting monstrosity with removeChild without triggering a script timeout :).