通过查阅android api，我们发现android.view.ViewGroup.MarginLayoutParams有个方法setMargins(left, top, right, bottom).
其直接的子类有: FrameLayout.LayoutParams, LinearLayout.LayoutParams and RelativeLayout.LayoutParams.
LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT);
lp.setMargins(10, 20, 30, 40);
imageView.setLayoutParams(lp);