android 运用代码实现 RelativeLayout布局

android 使用代码实现 RelativeLayout布局
只需把代码copy进入oncreate方法即可运行

 RelativeLayout rl = new RelativeLayout(this);                Button btn1 = new Button(this);        btn1.setText("----------------------");        btn1.setId(1);                RelativeLayout.LayoutParams lp1 = new RelativeLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);        lp1.addRule(RelativeLayout.ALIGN_PARENT_TOP);        lp1.addRule(RelativeLayout.CENTER_HORIZONTAL, RelativeLayout.TRUE);        // btn1 位于父 View 的顶部，在父 View 中水平居中        rl.addView(btn1, lp1 );               Button btn2 = new Button(this);        btn2.setText("|\n|\n|\n|\n|\n|");        btn2.setId(2);               RelativeLayout.LayoutParams lp2 = new RelativeLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);        lp2.addRule(RelativeLayout.BELOW, 1);        lp2.addRule(RelativeLayout.ALIGN_LEFT, 1);        // btn2 位于 btn1 的下方、其左边和 btn1 的左边对齐        rl.addView(btn2, lp2);               Button btn3 = new Button(this);        btn3.setText("|\n|\n|\n|\n|\n|");        btn3.setId(3);               RelativeLayout.LayoutParams lp3 = new RelativeLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);       lp3.addRule(RelativeLayout.BELOW, 1);        lp3.addRule(RelativeLayout.RIGHT_OF, 2);        lp3.addRule(RelativeLayout.ALIGN_RIGHT, 1);        // btn3 位于 btn1 的下方、btn2 的右方且其右边和 btn1 的右边对齐（要扩充）        rl.addView(btn3,lp3);               Button btn4 = new Button(this);        btn4.setText("--------------------------------------------");        btn4.setId(4);               RelativeLayout.LayoutParams lp4 = new RelativeLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);        lp4.addRule(RelativeLayout.BELOW, 2);        lp4.addRule(RelativeLayout.CENTER_HORIZONTAL, RelativeLayout.TRUE);        // btn4 位于 btn2 的下方，在父 Veiw 中水平居中        rl.addView(btn4,lp4);                      setContentView(rl);

代码参考自:
http://hi.baidu.com/xiechengfa/blog/item/5a3570eb3afb1a31b90e2d54.html, 有改动