Accessing layout from a different activity in Android Studio

Question

I'm still new in java and android studio. I want to know if there is a way to access a layout in another activity.

What I want is to be able to change the background image of my main activity through a different activity. So my main activity has a button that will direct them to a new activity, and that new activity has some buttons that will customize the background image of the main activity. (basically press a button and the background will change).

In my main.xml I got my constraint layout. How do I access that constraint layout in a different java class?

Answer 1

I think you can't do that. What you need is to pass some data to an activity you want to customize from your costomization activity with intent. The other way - you can use fragments, for example DialogFragment which is just attached to your mainactivity, so you can change it

Answer 2

@cupcake, You can access the object but you have to create the object name as static. and call from NewActivity But your view might be null if you dont call findViewbyId: Here and example : MainAcitvity

static TextView mTextViewTv;
static ConstraintLayout mLayoutCl;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    mTextViewTv = findViewById(R.id.helloWorldTv);
    mLayoutCl =findViewById(R.id.mLayout);
    mTextViewTv.setOnClickListener(v -> startNewActivity());
}


private void startNewActivity() {
    startActivity(new Intent(MainActivity.this,NewActivity.class));
}

NewActivity

 @Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_new);

  //you can call in on click, **Becareful with NUll expection**
//this is just example
  MainActivity.mLayoutCl.setBackgroundColor(getResources().getColor(R.color.black));
}

This type of method NOT RECOMMEND