How to customize the width and height when show an Activity as a Dialog

I finally figured out one way to customize the size of my DialogActivity.

That's inside the onCreate() method of DialogActivity, add the following code:

WindowManager.LayoutParams params = getWindow().getAttributes();  
params.x = -20;  
params.height = 100;  
params.width = 550;  
params.y = -10;  

this.getWindow().setAttributes(params); 

You can just change params of window in your acctivity like:

override fun onStart() {
        super.onStart()
        window.setLayout(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT)
    }