Continuously adding data to TextView freezes my app

Question

I'm developing an android application in which I have a thread that continuously generates data to be appended in a Textview, I use an Handler for this but after 1 or 2 secs my app just freezes.

The code is something like:

private class UpdateTextRunnable implements Runnable
{
    private String mBuffer = "";

    public void addLine( String line ) {
        mBuffer += line + "\n";
    }

    @Override
    public void run(){
        mTextView.setText( mBuffer );
    }
}

and in the thread a method from a custom interface is called every 0.5/1 sec :

    public void onMyCustomEvent( String data )
    {
      // mUpdater is an instance of UpdateTextRunnable
      mUpdater.addLine( data );
      // mHandler is an instance of Handler inside the main activity
      mHandler.post( mUpdater );
    }

What am I doing wrong ? :) Thanks

onMyCustom event is called as expected, so the addLine ... by the app is freezed :S — Simone Margaritelli, Aug 28 '12 at 19:44
and a lot of "D/dalvikvm(4831): WAIT_FOR_CONCURRENT_GC blocked 21ms" — Simone Margaritelli, Aug 28 '12 at 19:45
looks like you are updating entire text of `TextView` each time. Might be good to append instead. — S.D., Aug 28 '12 at 19:48
Try `getEditableText()` and append to that, but i doubt it will update `TextView`. — S.D., Aug 28 '12 at 19:55
it's updating, but the problem persists ... i thinks it's a matter of how big the content is — Simone Margaritelli, Aug 28 '12 at 20:02
check number 4 tutorial [HERE](http://www.vogella.com/articles/AndroidPerformance/article.html#concurrency_handler) , This code updates a progressBar from other thread using a handler. Use the same pattern for your `TextView`. Other approaches also shown here. — S.D., Aug 28 '12 at 20:12

score 0 · Answer 1 · answered Aug 28 '12 at 19:45

0

try StringBuilder instead of the String.

Example:

private class UpdateTextRunnable implements Runnable
{
    private StringBuilder mSB = "";

    public void addLine(String line) {
        mSB.append(line + "\n");
    }

    @Override
    public void run() {
        mTextView.setText(mSB.toString());
    }
}

answered Aug 28 '12 at 19:45

renyi

11
1

StringBuilder is already a CharSequence btw, no need for the #toString(). – Jens Aug 28 '12 at 19:48
try this http://stackoverflow.com/questions/5188295/how-to-change-a-textview-every-second-in-android – renyi Aug 28 '12 at 19:59

Continuously adding data to TextView freezes my app

1 Answers1