Update hello world example to match current behavior

[mattrenquist]

The current hello world example does not run. Adding 'textDirection' to match the code in examples/hello_world/lib/main.dart fixes the bug and allows the code to run. The website documentation should be updated to match the current code.

[googlebot]

Thanks for your pull request. It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

📝 Please visit https://cla.developers.google.com/ to sign.

Once you've signed, please reply here (e.g. I signed it!) and we'll verify. Thanks.

---

• If you've already signed a CLA, it's possible we don't have your GitHub username or you're using a different email address. Check your existing CLA data and verify that your email is set on your git commits.
• If your company signed a CLA, they designated a Point of Contact who decides which employees are authorized to participate. You may need to contact the Point of Contact for your company and ask to be added to the group of authorized contributors. If you don't know who your Point of Contact is, direct the project maintainer to go/cla#troubleshoot.
• In order to pass this check, please resolve this problem and have the pull request author add another comment and the bot will run again.

[mattrenquist]

Signed the CLA on 10:30 PST 9/17/2017.

[googlebot]

CLAs look good, thanks!

[Hixie]

Can you add a space after the comma?

[Hixie]

The Travis failure is because we're requiring the use of dartfmt, but here dartfmt is making the code uglier by wrapping in a poor way. We should probably exclude this file from dartfmt verification.

cc @sethladd

[mattrenquist]

Added the space. Thanks.

[Hixie]

or maybe we can tell dartfmt to accept longer lines? iirc @mit-mit solved our most recent issue with Travis in this repo, maybe he has a quick way to address this one too. :-)

[mit-mit]

dartfmt can be passed a --line-length argument to specify a longer wrapping length than it's default of 80. But we invoke dartfmt in a single location for all formating checks, so would need to make that change globally.

[mit-mit]

@Hixie @sethladd did you figure out how we want to handle this formatting issue?

[Hixie]

I have no particular opinion on how to solve this. I don't think dartfmt can handle this code in a good way. I'd be fine with excluding this file, changing the line width globally (assuming it doesn't make anything else worse), not using dartfmt at all, or any other similar solution.

[Sfshaza]

A longer-than-80-char line length means that code can wrap and look bad when displayed inside a web page.

[sethladd]

Or, add trailing commas to the snippet, reformat it with dartfmt

[Hixie]

@sethladd or @Sfshaza, can one of you update this to be wrapped as the Web site expects and then land this? Thanks!

[mit-mit]

I suggest we just add some trailing commas and auto-format, which would give us:

import 'package:flutter/material.dart';

void main() {
  runApp(
    new Center(
      child: new Text(
        'Hello, world!',
        textDirection: TextDirection.ltr,
      ),
    ),
  );
}

[sethladd]

formatting lgtm

[mit-mit]

Pushed that change to this PR

[mit-mit]

Travis is happy now, merging.

@mattrenquist thanks for contributing, and sorry for being so slow with this PR.

[mattrenquist]

No worries. Glad I could help out even a little. Thanks.