代码实现Layout android:layout_alignParentRight
代码实现Layout android:layout_alignParentRight
例如：
android: />
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RelativeLayout rl = new RelativeLayout(this);
MarginLayoutParams mp = new MarginLayoutParams(20,20); //item的宽高
mp.setMargins(0, 0, 25, 0);//分别是margin_top那四个属性
LayoutParams lp = new LayoutParams(mp);
lp.addRule(RelativeLayout.ALIGN_PARENT_RIGHT);
Button bt = new Button(this);
bt.setLayoutParams(lp);
rl.addView(bt);