Programmatically add Button to ConstrainLayout with ConstraintSet

Question

GoodDay everyone.

Im trying to add a button programmatically to a ConstraintLayout and set ConstraintSet to such button. The problem comes when I try to close the constraintSet from the layout as the button I've added has no ID.

Button button = new Button(this);

ConstraintLayout.LayoutParams params = new ConstraintLayout.LayoutParams(250, ConstraintLayout.LayoutParams.WRAP_CONTENT);
params.setMargins(15,15,15,15);

button.setLayoutParams(params);
button.setText(returnObject.getFunction());
button.setTextAlignment(View.TEXT_ALIGNMENT_CENTER);
button.setTextColor(R.drawable.custom_button_color);
button.setBackgroundResource(R.drawable.custom_button);

ConstraintLayout container = findViewById(R.id.highLevelContainer);
container.addView(button);

ConstraintSet constraintSet = new ConstraintSet();
constraintSet.clone(container); // Here I get the error
constraintSet.connect(button.getId(), ConstraintSet.END , container.getId(), ConstraintSet.END,0);
constraintSet.connect(button.getId(), ConstraintSet.START, container.getId(),ConstraintSet.START,0);
constraintSet.connect(button.getId(), ConstraintSet.TOP, container.getId(), ConstraintSet.TOP);
constraintSet.applyTo(container);

This is the generated error on the console:

java.lang.RuntimeException: All children of ConstraintLayout must have ids to use ConstraintSet
    at android.support.constraint.ConstraintSet.clone

I would like to avoid assigning a random number to the button as ID as it's created in a loop. Any idea how to fix this?

If you want to avoid a random number using `setId(View.generateViewId())` for example , what id do you expect to set to your child view ? — Ben Shmuel, Jun 18 '19 at 09:21

score 0 · Answer 1 · answered Oct 18 '21 at 11:30

You should simply add the id to your button:

Button button = new Button(this);

ConstraintLayout.LayoutParams params = new ConstraintLayout.LayoutParams(250, ConstraintLayout.LayoutParams.WRAP_CONTENT);
params.setMargins(15,15,15,15);

button.setLayoutParams(params);
button.setText(returnObject.getFunction());

button.setId(View.generateViewId());   <----HERE

button.setTextAlignment(View.TEXT_ALIGNMENT_CENTER);
button.setTextColor(R.drawable.custom_button_color);
button.setBackgroundResource(R.drawable.custom_button);

ConstraintLayout container = findViewById(R.id.highLevelContainer);
container.addView(button);

ConstraintSet constraintSet = new ConstraintSet();
constraintSet.clone(container); 
constraintSet.connect(button.getId(), ConstraintSet.END , container.getId(), ConstraintSet.END,0);
constraintSet.connect(button.getId(), ConstraintSet.START, container.getId(),ConstraintSet.START,0);
constraintSet.connect(button.getId(), ConstraintSet.TOP, container.getId(), ConstraintSet.TOP);
constraintSet.applyTo(container);

Programmatically add Button to ConstrainLayout with ConstraintSet

1 Answers1