How can I do something like a FlowLayout in Android?

You should use FlexboxLayout with flexWrap="wrap" attribute.

<com.google.android.flexbox.FlexboxLayout 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" 
     app:flexWrap="wrap">

<!-- contents go here -->

</com.google.android.flexbox.FlexboxLayout>

For build instructions, see the github repo.

implementation 'com.google.android:flexbox:2.0.1'

More about this - https://android-developers.googleblog.com/2017/02/build-flexible-layouts-with.html

There is a library from Google, called "flexbox-layout". You should check it out.

To use it in RecyclerView, you can use something like that:

val layoutManager = FlexboxLayoutManager(activity)
layoutManager.flexDirection = FlexDirection.ROW
layoutManager.flexWrap = FlexWrap.WRAP
layoutManager.justifyContent = JustifyContent.FLEX_START
layoutManager.alignItems = AlignItems.FLEX_START 
recyclerView.layoutManager=layoutManager

There is now built in support in ConstraintLayout using a Flow widget. It has many options that can be used to achieve many type of flows.

Example:

<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">

<androidx.constraintlayout.helper.widget.Flow
    android:layout_width="0dp"
    android:layout_height="wrap_content"
    app:constraint_referenced_ids="item_1,item_2,item_3"
    app:flow_horizontalBias="0"
    app:flow_horizontalGap="10dp"
    app:flow_horizontalStyle="packed"
    app:flow_verticalGap="8dp"
    app:flow_wrapMode="aligned"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent" />

<View
    android:id="@+id/item_1"
    android:layout_width="50dp"
    android:layout_height="50dp" />

<View
    android:id="@+id/item_2"
    android:layout_width="50dp"
    android:layout_height="50dp" />

<View
    android:id="@+id/item_3"
    android:layout_width="50dp"
    android:layout_height="50dp" />
</androidx.constraintlayout.widget.ConstraintLayout>

Take a look in this post: https://medium.com/@tapanrgohil/constraintlayout-flow-bye-bye-to-linerlayout-78fd7fa9b679

And here: https://www.bignerdranch.com/blog/constraintlayout-flow-simple-grid-building-without-nested-layouts/

I don't have enough reputation to post a comment to Romain Guy's answer but that's where this answer should be (I created an account just to share my edit).

Anyway, I see other people have found out his pretty cool FlowLayout solution has some issues. I could find one myself and I saw, as others, that some children were clipped. Looking in details at the algorithm it seems to be a very simple mistake in the calculation of the height. When the very last child is the one being put on a new line, then the height was not properly computed. I cleaned up a bit the computation (there was a weird use of "height" vs. currentHeight).

The following change fixes the problem of "last child is clipped if on a new line":

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
{
    int widthLimit = MeasureSpec.getSize(widthMeasureSpec) - getPaddingRight();
    int widthMode = MeasureSpec.getMode(widthMeasureSpec);

    boolean growHeight = widthMode != MeasureSpec.UNSPECIFIED;

    int width = 0;

    int currentWidth = getPaddingLeft();
    int currentHeight = getPaddingTop();

    int maxChildHeight = 0;

    boolean breakLine = false;
    boolean newLine = false;
    int spacing = 0;

    final int count = getChildCount();
    for (int i = 0; i < count; i++)
    {
        View child = getChildAt(i);
        measureChild(child, widthMeasureSpec, heightMeasureSpec);

        LayoutParams lp = (LayoutParams) child.getLayoutParams();
        spacing = mHorizontalSpacing;

        if (lp.horizontalSpacing >= 0)
        {
            spacing = lp.horizontalSpacing;
        }

        if (growHeight && (breakLine || ((currentWidth + child.getMeasuredWidth()) > widthLimit)))
        {               
            newLine = true;
            currentHeight += maxChildHeight + mVerticalSpacing;

            width = Math.max(width, currentWidth - spacing);

            currentWidth = getPaddingLeft();
            maxChildHeight = 0;
        }
        else
        {
            newLine = false;
        }

        maxChildHeight = Math.max(maxChildHeight, child.getMeasuredHeight());

        lp.x = currentWidth;
        lp.y = currentHeight;

        currentWidth += child.getMeasuredWidth() + spacing;

        breakLine = lp.breakLine;
    }

    if (newLine == false)
    {
        width = Math.max(width, currentWidth - spacing);
    }

    width += getPaddingRight();
    int height = currentHeight + maxChildHeight + getPaddingBottom();

    setMeasuredDimension(resolveSize(width, widthMeasureSpec),
            resolveSize(height, heightMeasureSpec));
}