Button Width Match Parent : Flutter

问题:

I am new in Flutter so I want to know that how can I set a width to match parent layout width

 new Container(
              width: 200.0,
              padding: const EdgeInsets.only(top: 16.0),
              child: new RaisedButton(
                child: new Text(
                    "Submit",
                    style: new TextStyle(
                      color: Colors.white,
                    )
                ),
                colorBrightness: Brightness.dark,
                onPressed: () {
                  _loginAttempt(context);
                },
                color: Colors.blue,
              ),
            ),

I know about little bit on Expanded tag but Expanded expand view to both direction, i dont know how to do it. Help me if you know, Thanks in Advance.

回答1:

The correct solution would be to use the SizedBox.expand widget, which enforces its child to match its parent's size.

new SizedBox.expand(
  child: new RaisedButton(...),
)

There are many alternatives, which allows for more or less customisation :

new SizedBox(
  width: double.infinity,
  // height: double.infinity,
  child: new RaisedButton(...),
)

or using a ConstrainedBox

new ConstrainedBox(
    constraints: const BoxConstraints(minWidth: double.infinity),
    child: new RaisedButton(...),
)

回答2:

The size attribute can be provided using ButtonTheme with minWidth: double.infinity

ButtonTheme(
  minWidth: double.infinity,
  child: MaterialButton(
    onPressed: () {},
    child: Text('Raised Button'),
  ),
),

or after https://github.com/flutter/flutter/pull/19416 landed

MaterialButton(
  onPressed: () {},
  child: SizedBox.expand(
    width: double.infinity, 
    child: Text('Raised Button'),
  ),
),

回答3:

    new Container {
         width: double.infinity,
         child: new RaisedButton(...),
    }

回答4:

using a ListTile also works as well since a list fills the entire width:

new ListTile(
              title: new RaisedButton(...),
),

回答5:

The simplest way is to use a FlatButton wrapped inside a container, The Button by default takes the size of its parent and so assign a desired width to the container.

            Container(
                  color: Colors.transparent,
                  width: MediaQuery.of(context).size.width,
                  height: 60,
                  child: FlatButton(
                    shape: new RoundedRectangleBorder(
                      borderRadius: new BorderRadius.circular(30.0),
                    ),
                    onPressed: () {},
                    color: Colors.red[300],
                    child: Text(
                      "Button",
                      style: TextStyle(
                        color: Colors.black,
                        fontFamily: 'Raleway',
                        fontSize: 22.0,
                      ),
                    ),
                  ),
                )

the above widget produces the following output

回答6:

After some research, I found out some solution, and thanks to @Günter Zöchbauer,

I used column instead of Container and

set the property to column CrossAxisAlignment.stretch to Fill match parent of Button

    new Column(
              crossAxisAlignment: CrossAxisAlignment.stretch,
              children: <Widget>[
                new RaisedButton(
                  child: new Text(
                      "Submit",
                      style: new TextStyle(
                        color: Colors.white,
                      )
                  ),
                  colorBrightness: Brightness.dark,
                  onPressed: () {
                    _loginAttempt(context);
                  },
                  color: Colors.blue,
                ),
              ],
            ),

回答7:

 new SizedBox(
  width: 100.0,
     child: new RaisedButton(...),
)

回答8:

The Following code work for me

       ButtonTheme(
            minWidth: double.infinity,
            child: RaisedButton(child: Text("Click!!", style: TextStyle(color: Colors.white),), color: Colors.pink, onPressed: () {}))

回答9:

@Mohit Suthar,

Found one of the best solution for match parent to width as well as height as below

new Expanded(
          child: new Container(
              padding: EdgeInsets.all(16.0),
              margin: EdgeInsets.all(16.0),
              decoration: new BoxDecoration(
                  color: Colors.white,
                  borderRadius:
                      const BorderRadius.all(const Radius.circular(8.0)),
                  border: new Border.all(color: Colors.black, width: 1.0)),
              child: new Text("TejaDroid")),
        ), 

Here you can check that the Expanded Controller acquire whole remain width and height.

回答10:

This is working for me in a self contained widget.

  Widget signinButton() {
    return ButtonTheme(
      minWidth: double.infinity,
      child: new FlatButton(
        onPressed: () {},
        color: Colors.green[400],
        textColor: Colors.white,
        child: Text('Flat Button'),
      ),
    );
  }

// It can then be used in a class that contains a widget tree.