Equivalent of RelativeLayout in Flutter

Is there a way to implement something similar to what RelativeLayout does on Android?

In particular I'm looking for something similar to centerInParent, layout_below:<layout_id>, layout_above:<layout_id>, and alignParentLeft

For more reference on RelativeLayout: https://developer.android.com/reference/android/widget/RelativeLayout.LayoutParams.html

EDIT: here is an example of a layout relying on RelativeLayout

So in the image above, on top, the "tofu's Songs" text is aligned as centerInParent inside a RelativeLayout. Whereas the other 2 are alignParentLeft and alignParentRight

On each cell, where the fire icon is at, the number of likes on the bottom of it is aligned around the center of the flame icon. Also, the top and bottom title on each cell are aligned to the right and to the top and bottom of the image avatar, respectively.

Flutter layouts are usually built using a tree of Column, Row and Stack widgets. These widgets take constructor arguments that specify rules for how the children are laid out relative to the parent, and you can also influence layout of individual children by wrapping them in Expanded, Flexible, Positioned, Align, or Center widgets.

It is also possible to build complex layouts using CustomMultiChildLayout. This is how Scaffold is implemented internally, and an example of how to use it in an app appears in the Shrine demo. You can also use LayoutBuilder or CustomPaint, or go down a layer and extend RenderObject as shown in the sector example. Doing your layouts manually like this is more work and creates more potential for errors in corner cases, so I would try to get by with the high-level layout primitives if you can.

To answer your specific questions:

Use the leading and trailing arguments to AppBar to position your app bar elements. If you want to use a Row instead, use a mainAxisAlignment of MainAxisAlignment.spaceBetween.
Use a Row with a crossAxisAlignment of CrossAxisAlignment.center to position the fire icon and number underneath.
Use a Column with a mainAxisAlignment of MainAxisAlignment.spaceBetween to position your top and bottom title. (You should consider using ListTile to lay out the list tiles, but you'll lose control over the exact positioning if you do this.)

Here is a code snippet that implements the design you provided. In this example I used an IntrinsicHeight to determine the height of the song tiles, but you can improve the performance by hard coding them to a fixed height.

import 'package:flutter/material.dart';

void main() {
  runApp(new MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      title: 'Flutter Demo',
      theme: new ThemeData(
        brightness: Brightness.dark,
        primaryColorBrightness: Brightness.dark,
      ),
      home: new HomeScreen(),
      debugShowCheckedModeBanner: false,
    );
  }
}

class Song extends StatelessWidget {
  const Song({ this.title, this.author, this.likes });

  final String title;
  final String author;
  final int likes;

  @override
  Widget build(BuildContext context) {
    TextTheme textTheme = Theme
      .of(context)
      .textTheme;
    return new Container(
      margin: const EdgeInsets.symmetric(horizontal: 10.0, vertical: 5.0),
      padding: const EdgeInsets.symmetric(horizontal: 15.0, vertical: 10.0),
      decoration: new BoxDecoration(
        color: Colors.grey.shade200.withOpacity(0.3),
        borderRadius: new BorderRadius.circular(5.0),
      ),
      child: new IntrinsicHeight(
        child: new Row(
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: <Widget>[
            new Container(
              margin: const EdgeInsets.only(top: 4.0, bottom: 4.0, right: 10.0),
              child: new CircleAvatar(
                backgroundImage: new NetworkImage(
                  'http://thecatapi.com/api/images/get?format=src'
                    '&size=small&type=jpg#${title.hashCode}'
                ),
                radius: 20.0,
              ),
            ),
            new Expanded(
              child: new Container(
                child: new Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  mainAxisAlignment: MainAxisAlignment.spaceBetween,
                  children: <Widget>[
                    new Text(title, style: textTheme.subhead),
                    new Text(author, style: textTheme.caption),
                  ],
                ),
              ),
            ),
            new Container(
              margin: new EdgeInsets.symmetric(horizontal: 5.0),
              child: new InkWell(
                child: new Icon(Icons.play_arrow, size: 40.0),
                onTap: () {
                  // TODO(implement)
                },
              ),
            ),
            new Container(
              margin: new EdgeInsets.symmetric(horizontal: 5.0),
              child: new InkWell(
                child: new Column(
                  mainAxisAlignment: MainAxisAlignment.center,
                  crossAxisAlignment: CrossAxisAlignment.center,
                  children: <Widget>[
                    new Icon(Icons.favorite, size: 25.0),
                    new Text('${likes ?? ''}'),
                  ],
                ),
                onTap: () {
                  // TODO(implement)
                },
              ),
            ),
          ],
        ),
      ),
    );
  }
}

class Feed extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new ListView(
      children: [
        new Song(title: 'Trapadelic lobo', author: 'lillobobeats', likes: 4),
        new Song(title: 'Different', author: 'younglowkey', likes: 23),
        new Song(title: 'Future', author: 'younglowkey', likes: 2),
        new Song(title: 'ASAP', author: 'tha_producer808', likes: 13),
        new Song(title: '