How do I remove Flutter IconButton big padding?

问题

I want to have a row of IconButtons, all next to each other, but there seems to be a pretty big padding between the actual icon, and the IconButton limits. I've already set the padding on the button to 0.

This is my component, pretty straightforward:

class ActionButtons extends StatelessWidget {
  @override
    Widget build(BuildContext context) {
      return Container(
        color: Colors.lightBlue,
        margin: const EdgeInsets.all(0.0),
        padding: const EdgeInsets.all(0.0),
        child: Row(
          mainAxisAlignment: MainAxisAlignment.start,
          children: <Widget>[
            IconButton(
              icon: new Icon(ScanrIcons.reg),
              alignment: Alignment.center,
              padding: new EdgeInsets.all(0.0),
              onPressed: () {},
            ),
            IconButton(
              icon: new Icon(Icons.volume_up),
              alignment: Alignment.center,
              padding: new EdgeInsets.all(0.0),
              onPressed: () {},
            )
          ],
        ),
      );
    }
}

I want to get rid of most of the light blue space, have my icons start earlier on the left, and closer to each other, but I can't find the way to resize the IconButton itself.

I'm almost sure this space is taken by the button itself, 'cause if I change their alignments to centerRight and centerLeft they look like this:

Making the actual icons smaller doesn't help either, the button is still big:

thanks for the help

回答1:

It's not so much that there's a padding there. IconButton is a Material Design widget which follows the spec that tappable objects need to be at least 48px on each side. You can click into the IconButton implementation from any IDEs.

You can also semi-trivially take the icon_button.dart source-code and make your own IconButton that doesn't follow the Material Design specs since the whole file is just composing other widgets and is just 200 lines that are mostly comments.

回答2:

Two ways to workaround this issue.

Still Use IconButton

Wrap the IconButton inside a Container which has a width.

For example:

Container(
  padding: const EdgeInsets.all(0.0),
  width: 30.0, // you can adjust the width as you need
  child: IconButton(
  ),
),

Use GestureDetector instead of IconButton

You can also use GestureDetector instead of IconButton, recommended by Shyju Madathil.

GestureDetector( onTap: () {}, child: Icon(Icons.volume_up) ) 

回答3:

I was facing a similar issue trying to render an Icon at the location the user touches the screen. Unfortunately, the Icon class wraps your chosen icon in a SizedBox.

Reading a little of the Icon class source it turns out that each Icon can be treated as text:

Widget iconWidget = RichText(
      overflow: TextOverflow.visible,
      textDirection: textDirection,
      text: TextSpan(
        text: String.fromCharCode(icon.codePoint),
        style: TextStyle(
          inherit: false,
          color: iconColor,
          fontSize: iconSize,
          fontFamily: icon.fontFamily,
          package: icon.fontPackage,
        ),
      ),
    );

So, for instance, if I want to render Icons.details to indicate where my user just pointed, without any margin, I can do something like this:

Widget _pointer = Text(
      String.fromCharCode(Icons.details.codePoint),
      style: TextStyle(
        fontFamily: Icons.details.fontFamily,
        package: Icons.details.fontPackage,
        fontSize: 24.0,
        color: Colors.black
      ),
    );

Dart/Flutter source code is remarkably approachable, I highly recommend digging in a little!

回答4:

Wrapping the IconButton in a container simply wont work, instead use ClipRRect and add a material Widget with an Inkwell, just make sure to give the ClipRRect widget enough border Radius 😉.

ClipRRect(
    borderRadius: BorderRadius.circular(50),
    child : Material(
        child : InkWell(
            child : Padding(
                padding : const EdgeInsets.all(5),
                child : Icon(
                    Icons.favorite_border,
                    ),
                ),
            onTap : () {},
            ),
        ),
    )

回答5:

To show splash effect (ripple), use InkResponse:

InkResponse(
  Icon(Icons.volume_up),
  onTap: ...,
)

If needed, change icons size or add padding:

InkResponse(
  child: Padding(
    padding: ...,
    child: Icon(Icons.volume_up, size: ...),
  ),
  onTap: ...,
)

来源：https://stackoverflow.com/questions/50381157/how-do-i-remove-flutter-iconbutton-big-padding