Android：RelativeLayout的按鈕定位問題

Question

我想要這樣：B1應該在B0以下。 B2有權擁有B1。 像這樣：

B0
B1 B2

但是我的代碼產生了這個：

B0 B2
B1

此代碼有什么問題？：

RelativeLayout xml_layout = (RelativeLayout) findViewById(R.id.custom_layout_id);

Button[] b_test  = new Button[4];

b_test[1] = new Button(getContext());
b_test[1].setId(1);
b_test[1].setText("B0");
RelativeLayout.LayoutParams lp0 = new RelativeLayout.LayoutParams(70,70);
lp0.addRule(RelativeLayout.ALIGN_PARENT_LEFT);
xml_layout.addView(b_test[1], lp0);

b_test[2] = new Button(getContext());
b_test[2].setId(2);
b_test[2].setText("B1");
RelativeLayout.LayoutParams lp1 = new RelativeLayout.LayoutParams(70,70);
lp1.addRule(RelativeLayout.BELOW, b_test[1].getId());
xml_layout.addView(b_test[2], lp1);

b_test[3] = new Button(getContext());
b_test[3].setId(3);
b_test[3].setText("B2");
RelativeLayout.LayoutParams lp2 = new RelativeLayout.LayoutParams(70,70);
lp2.addRule(RelativeLayout.RIGHT_OF, b_test[2].getId());
xml_layout.addView(b_test[3], lp2);

Answer 1

添加以下行：

lp2.addRule(RelativeLayout.BELOW, b_test[1].getId());

而且你應該准備好了。