Autosizing of TextView doesn't work (Android O)

Question

I use new autosize feature added in support library 26. I read a documentation which can be found here : https://developer.android.com/preview/features/autosizing-textview.html

I suppose that it should work this way: You can enable auto-sizing with this attribute: app:autoSizeTextType="uniform". I think that TextView should use all available space to display a whole text (not just a part - it shouldn't be cropped) and the textSize should be as big as possible. If you need to limit a maximum or minimum size of the text then you can use these two attributes:

app:autoSizeMinTextSize="XXsp" // (you can also use px or dp values.) 

or

app:autoSizeMaxTextSize="XXsp" 

So far so good. Let's say that I need a TextView with 56dp width. I have texts with a different length and I want to set these texts to this TextView. It should be automatically resized so it displays the whole text (all characters + not cropped) in the biggest possible textSize.

This is my TextView:

<android.support.v7.widget.AppCompatTextView         android:id="@+id/vName"         style="@style/TextView.AutoSize"         android:layout_width="56dp"         android:gravity="bottom|center_horizontal"         android:maxLines="1"         app:autoSizeMinTextSize="1px"         app:autoSizeTextType="uniform"         app:layout_constraintBottom_toTopOf="@id/vGuideline"         app:layout_constraintLeft_toLeftOf="parent"         app:layout_constraintRight_toRightOf="parent" /> 

Unfortunately, the text view is cropped. I wanted to set this String as a text to the TextView above: "Groupa" but this is the result:

(TextView is inside ConstraintLayout with yellow circle background.)

As you can see the textview is not resized at all. Do you have any idea what to do?

Thanks.

Answer 1

Additional to the other correct answers I found another point which prevents autosizing to work.

Do not use android:singleLine="true" together with autosizing. Use the newer android:maxLines="1" instead.

Answer 2

I have tested this for a few situations, and have the below conclusion:

You must have bounded width and height. For example, if you set width to be match_parent but wrap_content for height, I think Android doesn't know that how high you want to stretch your text. In your example you don't have a specific height, so I think that's why it doesn't work.

For example:

I don't know why Android official document would use wrap_content as an example...

And as you can see I didn't use other attributes in my example, so it probably is not the problem of incorrect attributes.

And, yes, the TextView I am using is android.support.v7.widget.AppCompatTextView.

And as long as you are using support library 26.0.0 or above it is good enough.

EDIT:

As for ConstraintLayout, the principal is the same. You should have both bounded width and height, which means either one of below for each dimension:

1. You have specified an absolute value for that dimension (width or height)

2. You have set Constraint to both directions

For example:

UPDATE: (2017-09-21)

I have tested that unfortunately it seems it does not support custom typeface yet, which is a function published together in support library v26...