How to set a maximum width for a view in an android constraintLayout?

Question

I have a layout that looks like this:

<?xml version="1.0" encoding="utf-8"?> <android.support.constraint.ConstraintLayout     xmlns:android="http://schemas.android.com/apk/res/android"     xmlns:app="http://schemas.android.com/apk/res-auto"     xmlns:tools="http://schemas.android.com/tools"     android:layout_width="match_parent"     android:layout_height="match_parent"     tools:context="com.plarke.proto1.QuizActivity">  <Button     android:id="@+id/compare_settings"     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:text="Button"     app:layout_constraintTop_toTopOf="parent"     android:layout_marginTop="16dp"     android:layout_marginRight="16dp"     app:layout_constraintRight_toRightOf="parent"     android:layout_marginEnd="16dp" />  <TextView     android:id="@+id/compare_score"     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:text="TextView"     app:layout_constraintTop_toTopOf="parent"     android:layout_marginTop="16dp"     android:layout_marginLeft="16dp"     app:layout_constraintLeft_toLeftOf="parent"     android:layout_marginStart="16dp" />  <SeekBar     android:id="@+id/compare_pitchbar"     android:layout_width="0dp"     android:layout_height="23dp"     android:layout_marginBottom="50dp"     android:layout_marginEnd="16dp"     android:layout_marginLeft="16dp"     android:layout_marginRight="16dp"     android:layout_marginStart="16dp"     android:progressBackgroundTint="@color/colorAccent"     android:progressBackgroundTintMode="src_over"     app:layout_constraintBottom_toTopOf="@+id/textView"     app:layout_constraintHorizontal_bias="0.0"     app:layout_constraintLeft_toLeftOf="parent"     app:layout_constraintRight_toRightOf="parent" />  <Button     android:id="@+id/button2"     android:layout_width="0dp"     android:layout_height="wrap_content"     android:layout_marginBottom="16dp"     android:layout_marginLeft="16dp"     android:layout_marginRight="16dp"     android:text="Button"     app:layout_constraintBottom_toBottomOf="parent"     app:layout_constraintLeft_toLeftOf="parent"     app:layout_constraintRight_toRightOf="parent"     android:layout_marginStart="16dp"     android:layout_marginEnd="16dp" />  <TextView     android:id="@+id/textView"     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:layout_marginBottom="50dp"     app:layout_constraintBottom_toTopOf="@+id/button2"     tools:text="The seekbar is all the way to the left."     app:layout_constraintRight_toRightOf="parent"     app:layout_constraintLeft_toLeftOf="parent"     android:layout_marginRight="0dp"     android:layout_marginLeft="0dp" /> 

And I want to change it so that the seekBar defaults to a certain width, but if the screen isn't wide enough, it just fills the screen(with margins). I've tried setting layout_width, but then it just goes off the screen if too wide. Using max_width does nothing at all. Is what I want possible in a ConstrainstLayout? If not what should I use?

Answer 1

I think what you're looking for is matchConstraintMaxWidth attribute.

If you add it to your SeekBar with a value of, say, 200dp, keeping left and right constraints to the parent and a width of 0dp, it will stretch the view's width up to 200dp, but if there is more room it will stay at 200dp.

so your xml should look like this:

<SeekBar    ...     android:layout_width="0dp"     app:layout_constraintStart_toStartOf="parent"     app:layout_constraintEnd_toEndOf="parent"     app:layout_constraintWidth_max="200dp" /> 

you should also be able to set it programmatically with

ConstraintLayout.LayoutParams layoutParams = new ConstraintLayout.LayoutParams(0, 0); layoutParams.matchConstraintMaxWidth = ...