public void setContentView(View view) {
        ensureContent();
        if (view == null) {
            throw new IllegalArgumentException("Content view can't be null");
        }
        if (mContentContainer instanceof ViewGroup) {
            ViewGroup contentContainer = (ViewGroup) mContentContainer;
            if (mContentView == null) {
                contentContainer.addView(view);
            } else {
                int index = contentContainer.indexOfChild(mContentView);
                // replace content view
                contentContainer.removeView(mContentView);
                contentContainer.addView(view, index);
            }
            mContentView = view;
        } else {
            throw new IllegalStateException("Can't be used with a custom content view");
        }
    }
Set the content view to an explicit view. If the content view was installed earlier,
the content will be replaced with a new view.

@param view The desired content to display. Value can't be null.
@see #setContentView(int)
@see #getContentView()
progressfragment-native/src/com/devspark/progressfragment/ProgressFragment.java