通过编码方式实现软件的布局

程序运行结果图示：



需要注意的是：

1)一个控件只能有一个父元素，如果多次添加

09-02 11:01:34.785: E/AndroidRuntime(23954):

 java.lang.RuntimeException: Unable to start activity ComponentInfo{cn.itcast.codeui/cn.itcast.codeui.MainActivity}: java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the child's parent first.

1、把新建项目时的main.xml文件删除

2、MainActivity

package com.njupt.codeui;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.ViewGroup.LayoutParams;
import android.widget.Button;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.TextView;

public class MainActivity extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);

LayoutParams params = new LayoutParams(LayoutParams.FILL_PARENT,LayoutParams.FILL_PARENT);
LayoutParams params1 = new LayoutParams(LayoutParams.FILL_PARENT,LayoutParams.WRAP_CONTENT);
LayoutParams params2 = new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT);

LinearLayout linearLayout = new LinearLayout(this);
linearLayout.setOrientation(LinearLayout.VERTICAL);

TextView tv = new TextView(this);
tv.setText("请输入你的老婆的姓名");
linearLayout.addView(tv,params1);

EditText et = new EditText(this);
et.setText("章泽天");
linearLayout.addView(et,params1);

Button bt = new Button(this);
bt.setText("确定");
linearLayout.addView(bt,params2);

setContentView(linearLayout,params);

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}

}