如何适当调整图像大小并在android中设置其高度和宽度

I know this may strike out as a dumb question but i bet some of you had this problem before.From the screenshot,i am attempting to set an image in an activity.However my image brings up these spaces i dont know how to get rid of them.I mean is there a way,either in xml or to programmatically resize image to fit the height and width?In short,is there a way i can get rid of these spaces above and below? I know this may strike out as a dumb question b