Android : How to programmatically set layout_constraintRight_toRightOf "parent"

Question

I have a view in ConstrainLayout as follows.

<TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:maxWidth="260dp"
        android:textColor="#FFF"
        android:textSize="16sp"
        app:layout_constraintLeft_toLeftOf="@+id/parent"
        app:layout_constraintTop_toBottomOf="@id/message_date"
        android:id="@+id/text_main"
        />

I would like to change the view to either app:layout_constraintLeft_toLeftOf="@+id/parent" or layout_constraintLeft_toRightOf="@+id/parent" programmatically in recycleViewHolder based on some conditions.

Answer 1

Here is an example of setting a button to the bottom of parent view using java code:

ConstraintLayout constraintLayout;
ConstraintSet constraintSet;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    constraintLayout = (ConstraintLayout) findViewById(R.id.activity_main_constraint_layout);

    Button button = new Button(this);
    button.setText("Hello");
    constraintLayout.addView(button);

    constraintSet = new ConstraintSet();
    constraintSet.clone(constraintLayout);

    constraintSet.connect(button.getId(), ConstraintSet.LEFT, constraintLayout.getId(), ConstraintSet.RIGHT, 0);
    constraintSet.constrainDefaultHeight(button.getId(), 200);
    constraintSet.applyTo(constraintLayout);

}

to achieve something like this,

app:layout_constraintLeft_toLeftOf="@+id/parent" 

your java code should look like this

set.connect(YOURVIEW.getId(),ConstraintSet.LEFT,ConstraintSet.PARENT_ID,ConstraintSet.LEFT,0);

and to achieve something like this,

layout_constraintLeft_toRightOf="@+id/parent"

your java code should look like this,

set.connect(YOURVIEW.getId(),ConstraintSet.LEFT,ConstraintSet.PARENT_ID,ConstraintSet.RIGHT,0);

Here, I'm assuming android:id="@+id/parent" is the id of your parent ConstraintLayout .