Dennis Ritchie Dies Again

Yesterday many people on my Twitter timeline sharing an article about Dennis Ritchie's death:

Dennis Ritchie, Father of C and Co-Developer of Unix, Dies https://t.co/LxkCK6i1DE via @WIRED

— Om Malik (@om) October 13, 2016

I clicked through to read the article, which was from 2011. Why is this circulating again?

My guess is that some people were retweeting without bothering to read the article, and thought he died recently.

This makes me think of a reaction to a tweet I posted.

@chiuki @yuichi_araki are you sure?

— Michel Onwordi (@lupo342) February 19, 2016

I was furious. Why would I post something that I'm not sure about? I even backed it up with a slide. Why are you doubting me?

Took me a while to remember that that's what other people do. Say things even when they are only 60% sure. I look back at my career and cringe to think of all the times when other people were regarded more knowledgeable because they open their mouths even when they are not sure.

This time, I am happy that I checked the details before passing it on.

Constraint Layout: Icon Label Text

I am making one of those classic layouts: an icon with two lines of text. I would like to use vector drawable for the icon, and scale it according to the text sizes. I want the top edge of the icon to line up with the top edge of the first line of text, and the bottom edge of the icon to line up with the bottom edge of the second line.

How would I do that? With ConstraintLayout!

<ImageView
  android:id="@+id/flower_image"
  android:layout_width="0dp"
  android:layout_height="0dp"
  app:layout_constraintTop_toTopOf="@+id/label"
  app:layout_constraintBottom_toBottomOf="@+id/text"
  app:layout_constraintLeft_toLeftOf="parent"
  app:layout_constraintDimensionRatio="1:1"
  app:srcCompat="@drawable/ic_flower"/>
<TextView
  android:id="@+id/label"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  app:layout_constraintLeft_toRightOf="@+id/image"
  app:layout_constraintTop_toTopOf="parent"
  android:text="@string/flower"
  android:textSize="16sp"/>
<TextView
  android:id="@+id/text"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  app:layout_constraintTop_toBottomOf="@+id/label"
  app:layout_constraintLeft_toLeftOf="@+id/label"
  android:text="@string/jasmine"
  android:textSize="24sp"/>

The width and the height of the ImageView is 0dp. This tells ConstraintLayout to compute them by the constraints. In this case, the height of the ImageView is determined by these constraints:

app:layout_constraintTop_toTopOf="@+id/label"
app:layout_constraintBottom_toBottomOf="@+id/text"

The width is the same as the height.

app:layout_constraintDimensionRatio="1:1"

The rest of the constraints are for positioning.

With that, the image scales up as the text sizes increase. It stays sharp because it is a vector.

Layout Editor

I tried to make this layout with the Layout Editor, but could not figure out how to create the constraint app:layout_constraintTop_toTopOf="@+id/label" for the ImageView. I was hovering my cursor around the top edge but not sure how to drag it to link the two views. So I added up playing with the editor a bit to deduce the XML attributes, and switched to editing the XML directly. I hope to use the layout editor in my next attempt to use Constraint Layout.

Follow-up Twitter discussion:

@romainguy Just tried it again. Yes I can do the top & the bottom. Then I try to set the image view to 0x0 and things just go crazy.

— Chiu-Ki Chan (@chiuki) October 9, 2016

@chiuki @romainguy with 2.2, you do need to touch the XML for ratio & chains, yes

— Nicolas Roard (@camaelon) October 9, 2016

Read the whole Twitter thread.

Source code

github.com/chiuki/iconlabeltext

Click on either TextView to increase its size. Click on the image to reset.