Padding is the space inside the border, between the border and the actual view's content. Note that padding goes completely around the content: there is padding on the top, bottom, right and left sides (which can be independent).
Margins are the spaces outside the border, between the border and the other elements next to this view. In the image, the margin is the grey area outside the entire object. Note that, like the padding, the margin goes completely around the content: there are margins on the top, bottom, right, and left sides.
getwidth() is used to get width of view that has drawn like (view.getwidth() or view.getheight()).getwidth() and getHeight() will only be populated after the Layout Phase, that is after onLayout（）has been called.
getMeasureWidth() is used to get width of view that not drawn yet. like getmeasuredwidth() and getmeasureheight(). example : First call measure view.measure(0,0) and then u can use it with getmeasuredwidth() and getmeasureheight().
should not use getwidth/getHeight the values within onMeasure() or getMeasureWidth()/getMeasureWidth(), since those are only the dimensions the View is initially offered or would like to have, not necessarily the ones it actually ends up getting.
http://stackoverflow.com/questions/4142090/how-do-you-to-retrieve-dimensions-of-a-view-getheight-and-getwidth-always-r/4406090#4406090