以前在实现android界面的时候，也使用过java编码的方式，或者xml以及java混合，

但使用的是线性布局LinearLayout，相对来说直接的由上而下的加载，倒不是很难。

最近需要使用java编码实现相对不觉就显得有点复杂了，毕竟，相对布局需要指定的参数较多

下面有一个相对布局的例子，仅作参考：

public class TestCaseActivity extends Activity { //    /** Called when the activity is first created. */ //    @Override //    public void onCreate(Bundle savedInstanceState) { //        super.onCreate(savedInstanceState); //        setContentView(R.layout.main1); //    } //}     private RelativeLayout rl;           private Button btn1;      private Button btn2;      private Button btn3;      private Button btn4;          private static final int ID_BTN1 = 1;      private static final int ID_BTN2 = 2;      private static final int ID_BTN3 = 3;      private static final int ID_BTN4 = 4;          /** Called when the activity is first created. */      @Override      public void onCreate(Bundle icicle) {          super.onCreate(icicle);                  rl = new RelativeLayout(this);                  btn1 = new Button(this);          btn1.setText("1----------------------");          btn1.setId(ID_BTN1);                   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 );                  btn2 = new Button(this);          btn2.setText("2|\n|\n|\n|\n|\n|");          btn2.setId(ID_BTN2);                  RelativeLayout.LayoutParams lp2 = new RelativeLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT); //         lp2.addRule(RelativeLayout.POSITION_BELOW, ID_BTN1);          lp2.addRule(RelativeLayout.BELOW, ID_BTN1);          lp2.addRule(RelativeLayout.ALIGN_LEFT, ID_BTN1);          // btn2 位于 btn1 的下方、其左边和 btn1 的左边对齐          rl.addView(btn2, lp2);                  btn3 = new Button(this);          btn3.setText("3|\n|\n|\n|\n|\n|");          btn3.setId(ID_BTN3);                   RelativeLayout.LayoutParams lp3 = new RelativeLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);          lp3.addRule(RelativeLayout.BELOW, ID_BTN1);          lp3.addRule(RelativeLayout.RIGHT_OF, ID_BTN2);          lp3.addRule(RelativeLayout.ALIGN_RIGHT, ID_BTN1);          // 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);                  btn4 = new Button(this);          btn4.setText("4--------------------------------------------");          btn4.setId(ID_BTN4);                  RelativeLayout.LayoutParams lp4 = new RelativeLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);          lp4.addRule(RelativeLayout.BELOW, ID_BTN2);          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);      }  }