toast does not show android code example

Example 1: java android show toast

Toast myToast = Toast.makeText(this, "I'm a toast!", Toast.LENGTH_LONG);
myToast.show();

Example 2: android studio make toast appear at top of screen

// v is the Button view that you want the Toast to appear above 
// and messageId is the id of your string resource for the message

private void displayToastAboveButton(View v, int messageId)
{
    int xOffset = 0;
    int yOffset = 0;
    Rect gvr = new Rect();

    View parent = (View) v.getParent(); 
    int parentHeight = parent.getHeight();

    if (v.getGlobalVisibleRect(gvr)) 
    {       
        View root = v.getRootView();

        int halfWidth = root.getRight() / 2;
        int halfHeight = root.getBottom() / 2;

        int parentCenterX = ((gvr.right - gvr.left) / 2) + gvr.left;

        int parentCenterY = ((gvr.bottom - gvr.top) / 2) + gvr.top;

        if (parentCenterY <= halfHeight) 
        {
            yOffset = -(halfHeight - parentCenterY) - parentHeight;
        }
        else 
        {
            yOffset = (parentCenterY - halfHeight) - parentHeight;
        }

        if (parentCenterX < halfWidth) 
        {         
            xOffset = -(halfWidth - parentCenterX);     
        }   

        if (parentCenterX >= halfWidth) 
        {
            xOffset = parentCenterX - halfWidth;
        }  
    }

    Toast toast = Toast.makeText(getActivity(), messageId, Toast.LENGTH_SHORT);
    toast.setGravity(Gravity.CENTER, xOffset, yOffset);
    toast.show();       
}