Check out example codes for "show full screen popup in android". It will help you in understanding the concepts better.

Code Example 1

Rect displayRectangle = new Rect();
Window window = MainActivity.this.getWindow();
window.getDecorView().getWindowVisibleDisplayFrame(displayRectangle);
final AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this,R.style.CustomAlertDialog);
ViewGroup viewGroup = findViewById(android.R.id.content);
View dialogView = LayoutInflater.from(v.getContext()).inflate(R.layout.customview, viewGroup, false);
dialogView.setMinimumWidth((int)(displayRectangle.width() * 1f));
dialogView.setMinimumHeight((int)(displayRectangle.height() * 1f));
builder.setView(dialogView);
final AlertDialog alertDialog = builder.create();
Button buttonOk=dialogView.findViewById(R.id.buttonOk);
buttonOk.setOnClickListener(new View.OnClickListener() {
   @Override
   public void onClick(View v) {
      alertDialog.dismiss();
   }
});
alertDialog.show();

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