How to Add a Child View to the Center of a ViewGroup

Question

I have created a custom circular ProgressBar following this. Now I want to add this progress bar to the center of my layout. The problem is that it is added to the top left of the activity, no matter how I change LayoutParams attributes passed to addView(). The code is as follows:

// Create a progress bar to display while the list loads
            mProgressBar = new DualProgressView(getApplicationContext());

            ViewGroup root = findViewById(android.R.id.content);
            LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(500, 500, Gravity.CENTER);
            root.addView(mProgressBar,params);

Answer 1

1. make your progress bar height and width as wrap_content, or, say 40sp in xml.
2. set attribute android:layout_gravity="center" to your ProgressBar within your LinearLayout.

or programmatically, try this:

ViewGroup layout = (ViewGroup) findViewById(android.R.id.content).getRootView();
LinearLayout.LayoutParams params = new 
        LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT,LinearLayout.LayoutParams.MATCH_PARENT);

LinearLayout ll = new LinearLayout(thisActivity);

ll.setGravity(Gravity.CENTER);
ll.addView(progressBar);

layout.addView(ll,params);